13.5.47

Make encodeStateAsUpdate deterministic

.github/FUNDING.yml

@@ -1,12 +0,0 @@
-# These are supported funding model platforms
-
-github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
-patreon: dmonad
-open_collective: # Replace with a single Open Collective username
-ko_fi: # Replace with a single Ko-fi username
-tidelift: # Replace with a single Tidelift platform-name/package-name e.g., npm/babel
-community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
-liberapay: # Replace with a single Liberapay username
-issuehunt: # Replace with a single IssueHunt username
-otechie: # Replace with a single Otechie username
-custom: # Replace with up to 4 custom sponsorship URLs e.g., ['link1', 'link2']

.github/workflows/node.js.yml

@@ -0,0 +1,29 @@
+# This workflow will do a clean install of node dependencies, build the source code and run tests across different versions of node
+# For more information see: https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
+
+name: Node.js CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [10.x, 12.x, 14.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: npm ci
+    - run: npm run build --if-present
+    - run: npm test

.jsdoc.json

@@ -17,10 +17,13 @@
     "useCollapsibles": true,
     "collapse": true,
     "resources": {
-      "yjs.dev": "Yjs website"
+      "yjs.dev": "Website",
+      "docs.yjs.dev": "Docs",
+      "discuss.yjs.dev": "Forum",
+      "https://gitter.im/Yjs/community": "Chat"
     },
     "logo": {
-      "url": "https://user-images.githubusercontent.com/5553757/48975307-61efb100-f06d-11e8-9177-ee895e5916e5.png",
+      "url": "https://yjs.dev/images/logo/yjs-512x512.png",
       "width": "162px",
       "height": "162px",
       "link": "/"
@@ -35,7 +38,7 @@
     ],
     "default": {
       "staticFiles": {
-          "include": ["examples/"]
+          "include": []
       }
     }
   },
@@ -44,7 +47,6 @@
     "encoding": "utf8",
     "private": false,
     "recurse": true,
-    "template": "./node_modules/tui-jsdoc-template",
-    "tutorials": "./examples"
+    "template": "./node_modules/tui-jsdoc-template"
   }
 }

INTERNALS.md

@@ -0,0 +1,179 @@
+# Yjs Internals
+
+This document roughly explains how Yjs works internally. There is a complete
+walkthrough of the Yjs codebase available as a recording:
+https://youtu.be/0l5XgnQ6rB4
+
+The Yjs CRDT algorithm is described in the [YATA
+paper](https://www.researchgate.net/publication/310212186_Near_Real-Time_Peer-to-Peer_Shared_Editing_on_Extensible_Data_Types)
+from 2016. For an algorithmic view of how it works, the paper is a reasonable
+place to start. There are a handful of small improvements implemented in Yjs
+which aren't described in the paper. The most notable is that items have an
+`originRight` as well as an `origin` property, which improves performance when
+many concurrent inserts happen after the same character.
+
+At its heart, Yjs is a list CRDT. Everything is squeezed into a list in order to
+reuse the CRDT resolution algorithm:
+
+- Arrays are easy - they're lists of arbitrary items.
+- Text is a list of characters, optionally punctuated by formatting markers and
+  embeds for rich text support. Several characters can be wrapped in a single
+linked list `Item` (this is also known as the compound representation of
+CRDTs). More information about this in [this blog
+article](https://blog.kevinjahns.de/are-crdts-suitable-for-shared-editing/).
+- Maps are lists of entries. The last inserted entry for each key is used, and
+  all other duplicates for each key are flagged as deleted.
+
+Each client is assigned a unique *clientID* property on first insert. This is a
+random 53-bit integer (53 bits because that fits in the javascript safe integer
+range).
+
+## List items
+
+Each item in a Yjs list is made up of two objects:
+
+- An `Item` (*src/structs/Item.js*). This is used to relate the item to other
+  adjacent items.
+- An object in the `AbstractType` hierarchy (subclasses of
+  *src/types/AbstractType.js* - eg `YText`). This stores the actual content in
+the Yjs document.
+
+The item and type object pair have a 1-1 mapping. The item's `content` field
+references the AbstractType object and the AbstractType object's `_item` field
+references the item.
+
+Everything inserted in a Yjs document is given a unique ID, formed from a
+*ID(clientID, clock)* pair (also known as a [Lamport
+Timestamp](https://en.wikipedia.org/wiki/Lamport_timestamp)). The clock counts
+up from 0 with the first inserted character or item a client makes. This is
+similar to automerge's operation IDs, but note that the clock is only
+incremented by inserts. Deletes are handled in a very different way (see
+below).
+
+If a run of characters is inserted into a document (eg `"abc"`), the clock will
+be incremented for each character (eg 3 times here). But Yjs will only add a
+single `Item` into the list. This has no effect on the core CRDT algorithm, but
+the optimization dramatically decreases the number of javascript objects
+created during normal text editing. This optimization only applies if the
+characters share the same clientID, they're inserted in order, and all
+characters have either been deleted or all characters are not deleted. The item
+will be split if the run is interrupted for any reason (eg a character in the
+middle of the run is deleted).
+
+When an item is created, it stores a reference to the IDs of the preceeding and
+succeeding item. These are stored in the item's `origin` and `originRight`
+fields, respectively. These are used when peers concurrently insert at the same
+location in a document. Though quite rare in practice, Yjs needs to make sure
+the list items always resolve to the same order on all peers. The actual logic
+is relatively simple - its only a couple dozen lines of code and it lives in
+the `Item#integrate()` method. The YATA paper has much more detail on this
+algorithm.
+
+### Item Storage
+
+The items themselves are stored in two data structures and a cache:
+
+- The items are stored in a tree of doubly-linked lists in *document order*.
+  Each item has `left` and `right` properties linking to its siblings in the
+document. Items also have a `parent` property to reference their parent in the
+document tree (null at the root). (And you can access an item's children, if
+any, through `item.content`).
+- All items are referenced in *insertion order* inside the struct store
+  (*src/utils/StructStore.js*). This references the list of items inserted by
+for each client, in chronological order. This is used to find an item in the
+tree with a given ID (using a binary search). It is also used to efficiently
+gather the operations a peer is missing during sync (more on this below).
+
+When a local insert happens, Yjs needs to map the insert position in the
+document (eg position 1000) to an ID. With just the linked list, this would
+require a slow O(n) linear scan of the list. But when editing a document, most
+inserts are either at the same position as the last insert, or nearby. To
+improve performance, Yjs stores a cache of the 10 most recently looked up
+insert positions in the document. This is consulted and updated when a position
+is looked up to improve performance in the average case. The cache is updated
+using a heuristic that is still changing (currently, it is updated when a new
+position significantly diverges from existing markers in the cache). Internally
+this is referred to as the skip list / fast search marker.
+
+### Deletions
+
+Deletions in Yjs are treated very differently from insertions. Insertions are
+implemented as a sequential operation based CRDT, but deletions are treated as
+a simpler state based CRDT.
+
+When an item has been deleted by any peer, at any point in history, it is
+flagged as deleted on the item. (Internally Yjs uses the `info` bitfield.) Yjs
+does not record metadata about a deletion:
+
+- No data is kept on *when* an item was deleted, or which user deleted it.
+- The struct store does not contain deletion records
+- The clientID's clock is not incremented
+
+If garbage collection is enabled in Yjs, when an object is deleted its content
+is discarded. If a deleted object contains children (eg a field is deleted in
+an object), the content is replaced with a `GC` object (*src/structs/GC.js*).
+This is a very lightweight structure - it only stores the length of the removed
+content.
+
+Yjs has some special logic to share which content in a document has been
+deleted:
+
+- When a delete happens, as well as marking the item, the deleted IDs are
+  listed locally within the transaction. (See below for more information about
+transactions.) When a transaction has been committed locally, the set of
+deleted items is appended to a transaction's update message.
+- A snapshot (a marked point in time in the Yjs history) is specified using
+  both the set of (clientID, clock) pairs *and* the set of all deleted item
+IDs. The deleted set is O(n), but because deletions usually happen in runs,
+this data set is usually tiny in practice. (The real world editing trace from
+the B4 benchmark document contains 182k inserts and 77k deleted characters. The
+deleted set size in a snapshot is only 4.5Kb).
+
+## Transactions
+
+All updates in Yjs happen within a *transaction*. (Defined in
+*src/utils/Transaction.js*.)
+
+The transaction collects a set of updates to the Yjs document to be applied on
+remote peers atomically. Once a transaction has been committed locally, it
+generates a compressed *update message* which is broadcast to synchronized
+remote peers to notify them of the local change. The update message contains:
+
+- The set of newly inserted items
+- The set of items deleted within the transaction.
+
+## Network protocol
+
+The network protocol is not really a part of Yjs. There are a few relevant
+concepts that can be used to create a custom network protocol:
+
+* `update`: The Yjs document can be encoded to an *update* object that can be
+  parsed to reconstruct the document. Also every change on the document fires
+an incremental document updates that allows clients to sync with each other.
+The update object is an Uint8Array that efficiently encodes `Item` objects and
+the delete set.
+* `state vector`: A state vector defines the known state of each user (a set of
+  tuples `(client, clock)`). This object is also efficiently encoded as a
+Uint8Array.
+
+The client can ask a remote client for missing document updates by sending
+their state vector (often referred to as *sync step 1*). The remote peer can
+compute the missing `Item` objects using the `clocks` of the respective clients
+and compute a minimal update message that reflects all missing updates (sync
+step 2).
+
+An implementation of the syncing process is in
+[y-protocols](https://github.com/yjs/y-protocols).
+
+## Snapshots
+
+A snapshot can be used to restore an old document state. It is a `state vector`
+\+ `delete set`. A client can restore an old document state by iterating through
+the sequence CRDT and ignoring all Items that have an `id.clock >
+stateVector[id.client].clock`. Instead of using `item.deleted` the client will
+use the delete set to find out if an item was deleted or not.
+
+It is not recommended to restore an old document state using snapshots,
+although that would certainly be possible. Instead, the old state should be
+computed by iterating through the newest state and using the additional
+information from the state vector.

README.md

@@ -15,15 +15,51 @@ suited for even large documents.
 
 * Demos: [https://github.com/yjs/yjs-demos](https://github.com/yjs/yjs-demos)
 * Discuss: [https://discuss.yjs.dev](https://discuss.yjs.dev)
+* Chat: [Gitter](https://gitter.im/Yjs/community) | [Discord](https://discord.gg/T3nqMT6qbM)
 * Benchmark Yjs vs. Automerge:
   [https://github.com/dmonad/crdt-benchmarks](https://github.com/dmonad/crdt-benchmarks)
 * Podcast [**"Yjs Deep Dive into real time collaborative editing solutions":**](https://www.tag1consulting.com/blog/deep-dive-real-time-collaborative-editing-solutions-tagteamtalk-001-0)
 * Podcast [**"Google Docs-style editing in Gutenberg with the YJS framework":**](https://publishpress.com/blog/yjs/)
 
-:construction_worker_woman: If you are looking for professional (paid) support to
-build collaborative or distributed applications ping us at
-<yjs@tag1consulting.com>. Otherwise you can find help on our
-[discussion board](https://discuss.yjs.dev).
+:construction_worker_woman: If you are looking for professional support, please
+consider supporting this project via a "support contract" on
+[GitHub Sponsors](https://github.com/sponsors/dmonad). I will attend your issues
+quicker and we can discuss questions and problems in regular video conferences.
+Otherwise you can find help on our community [discussion board](https://discuss.yjs.dev).
+
+## Sponsorship
+
+Please contribute to the project financially - especially if your company relies
+on Yjs. [![Become a Sponsor](https://img.shields.io/static/v1?label=Become%20a%20Sponsor&message=%E2%9D%A4&logo=GitHub&style=flat&color=d42f2d)](https://github.com/sponsors/dmonad)
+
+## Who is using Yjs
+
+* [AFFiNE](https://affine.pro/) A local-first, privacy-first, open source
+  knowledge base. 🏅
+* [Dynaboard](https://dynaboard.com/) Build web apps collaboratively. :star2:
+* [Sana](https://sanalabs.com/) A learning platform with collaborative text
+  editing powered by Yjs.
+* [Relm](https://www.relm.us/) A collaborative gameworld for teamwork and
+  community. :star:
+* [Room.sh](https://room.sh/) A meeting application with integrated
+  collaborative drawing, editing, and coding tools. :star:
+* [Nimbus Note](https://nimbusweb.me/note.php) A note-taking app designed by
+  Nimbus Web. :star:
+* [Pluxbox RadioManager](https://getradiomanager.com/) A web-based app to
+  collaboratively organize radio broadcasts. :star:
+* [Serenity Notes](https://www.serenity.re/en/notes) End-to-end encrypted
+  collaborative notes app.
+* [PRSM](https://prsm.uk/) Collaborative mind-mapping and system visualisation. *[(source)](https://github.com/micrology/prsm)*
+* [Alldone](https://alldone.app/) A next-gen project management and
+  collaboration platform.
+* [Living Spec](https://livingspec.com/) A modern way for product teams to collaborate.
+* [Slidebeamer](https://slidebeamer.com/) Presentation app.
+* [BlockSurvey](https://blocksurvey.io) End-to-end encryption for your forms/surveys.
+* [Skiff](https://skiff.org/) Private, decentralized workspace.
+* [Hyperquery](https://hyperquery.ai/) A collaborative data workspace for
+  sharing analyses, documentation, spreadsheets, and dashboards.
+* [Nosgestesclimat](https://nosgestesclimat.fr/groupe) The french carbon
+  footprint calculator has a group P2P mode based on yjs
 
 ## Table of Contents
 
@@ -37,8 +73,6 @@ build collaborative or distributed applications ping us at
   * [Document Updates](#Document-Updates)
   * [Relative Positions](#Relative-Positions)
   * [Y.UndoManager](#YUndoManager)
-* [Miscellaneous](#Miscellaneous)
-  * [Typescript Declarations](#Typescript-Declarations)
 * [Yjs CRDT Algorithm](#Yjs-CRDT-Algorithm)
 * [License and Author](#License-and-Author)
 
@@ -52,10 +86,14 @@ are implemented in separate modules.
 
 | Name | Cursors | Binding |  Demo |
 |---|:-:|---|---|
-| [ProseMirror](https://prosemirror.net/) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; | ✔ | [y-prosemirror](http://github.com/yjs/y-prosemirror) | [demo](https://demos.yjs.dev/prosemirror/prosemirror.html) |
-| [Quill](https://quilljs.com/) | ✔ | [y-quill](http://github.com/yjs/y-quill) | [demo](https://demos.yjs.dev/quill/quill.html) |
-| [CodeMirror](https://codemirror.net/) | ✔ | [y-codemirror](http://github.com/yjs/y-codemirror) | [demo](https://demos.yjs.dev/codemirror/codemirror.html) |
-| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](http://github.com/yjs/y-monaco) | [demo](https://demos.yjs.dev/monaco/monaco.html) |
+| [ProseMirror](https://prosemirror.net/) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; | ✔ | [y-prosemirror](https://github.com/yjs/y-prosemirror) | [demo](https://demos.yjs.dev/prosemirror/prosemirror.html) |
+| [Quill](https://quilljs.com/) | ✔ | [y-quill](https://github.com/yjs/y-quill) | [demo](https://demos.yjs.dev/quill/quill.html) |
+| [CodeMirror](https://codemirror.net/) | ✔ | [y-codemirror](https://github.com/yjs/y-codemirror) | [demo](https://demos.yjs.dev/codemirror/codemirror.html) |
+| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](https://github.com/yjs/y-monaco) | [demo](https://demos.yjs.dev/monaco/monaco.html) |
+| [Slate](https://github.com/ianstormtaylor/slate) | ✔ | [slate-yjs](https://github.com/bitphinix/slate-yjs) | [demo](https://bitphinix.github.io/slate-yjs-example) |
+| [valtio](https://github.com/pmndrs/valtio) |  | [valtio-yjs](https://github.com/dai-shi/valtio-yjs) | [demo](https://codesandbox.io/s/valtio-yjs-demo-ox3iy) |
+| [immer](https://github.com/immerjs/immer) |  | [immer-yjs](https://github.com/sep2/immer-yjs) | [demo](https://codesandbox.io/s/immer-yjs-demo-6e0znb) |
+| React / Vue / Svelte / MobX | | [SyncedStore](https://syncedstore.org) | [demo](https://syncedstore.org/docs/react) |
 
 ### Providers
 
@@ -65,7 +103,7 @@ manage all that for you and are the perfect starting point for your
 collaborative app.
 
 <dl>
-  <dt><a href="http://github.com/yjs/y-webrtc">y-webrtc</a></dt>
+  <dt><a href="https://github.com/yjs/y-webrtc">y-webrtc</a></dt>
   <dd>
 Propagates document updates peer-to-peer using WebRTC. The peers exchange
 signaling data over signaling servers. Publically available signaling servers
@@ -73,24 +111,44 @@ are available. Communication over the signaling servers can be encrypted by
 providing a shared secret, keeping the connection information and the shared
 document private.
   </dd>
-  <dt><a href="http://github.com/yjs/y-websocket">y-websocket</a></dt>
+  <dt><a href="https://github.com/yjs/y-websocket">y-websocket</a></dt>
   <dd>
 A module that contains a simple websocket backend and a websocket client that
 connects to that backend. The backend can be extended to persist updates in a
 leveldb database.
   </dd>
-  <dt><a href="http://github.com/yjs/y-indexeddb">y-indexeddb</a></dt>
+  <dt><a href="https://github.com/yjs/y-indexeddb">y-indexeddb</a></dt>
   <dd>
 Efficiently persists document updates to the browsers indexeddb database.
 The document is immediately available and only diffs need to be synced through the
 network provider.
   </dd>
-  <dt><a href="http://github.com/yjs/y-dat">y-dat</a></dt>
+  <dt><a href="https://github.com/marcopolo/y-libp2p">y-libp2p</a></dt>
   <dd>
-[WIP] Write document updates effinciently to the dat network using
+Uses <a href="https://libp2p.io/">libp2p</a> to propagate updates via
+<a href="https://github.com/libp2p/specs/tree/master/pubsub/gossipsub">GossipSub</a>.
+Also includes a peer-sync mechanism to catch up on missed updates.
+  </dd>
+  <dt><a href="https://github.com/yjs/y-dat">y-dat</a></dt>
+  <dd>
+[WIP] Write document updates efficiently to the dat network using
 <a href="https://github.com/kappa-db/multifeed">multifeed</a>. Each client has
 an append-only log of CRDT local updates (hypercore). Multifeed manages and sync
 hypercores and y-dat listens to changes and applies them to the Yjs document.
+</dd>
+  <dt><a href="https://github.com/yousefED/matrix-crdt">Matrix-CRDT</a></dt>
+  <dd>
+Use <a href="https://www.matrix.org">Matrix</a> as an off-the-shelf backend for
+Yjs by using the <a href="https://github.com/yousefED/matrix-crdt">MatrixProvider</a>.
+Use Matrix as transport and storage of Yjs updates, so you can focus building
+your client app and Matrix can provide powerful features like Authentication,
+Authorization, Federation, hosting (self-hosting or SaaS) and even End-to-End
+Encryption (E2EE).
+</dd>
+  <dt><a href="https://github.com/MaxNoetzold/y-mongodb-provider">y-mongodb-provider</a></dt>
+  <dd>
+Adds persistent storage to a server with MongoDB. Can be used with the
+y-websocket provider.
 </dd>
 </dl>
 
@@ -137,6 +195,54 @@ Now you understand how types are defined on a shared document. Next you can jump
 to the [demo repository](https://github.com/yjs/yjs-demos) or continue reading
 the API docs.
 
+### Example: Using and combining providers
+
+Any of the Yjs providers can be combined with each other. So you can sync data
+over different network technologies.
+
+In most cases you want to use a network provider (like y-websocket or y-webrtc)
+in combination with a persistence provider (y-indexeddb in the browser).
+Persistence allows you to load the document faster and to persist data that is
+created while offline.
+
+For the sake of this demo we combine two different network providers with a
+persistence provider.
+
+```js
+import * as Y from 'yjs'
+import { WebrtcProvider } from 'y-webrtc'
+import { WebsocketProvider } from 'y-websocket'
+import { IndexeddbPersistence } from 'y-indexeddb'
+
+const ydoc = new Y.Doc()
+
+// this allows you to instantly get the (cached) documents data
+const indexeddbProvider = new IndexeddbPersistence('count-demo', ydoc)
+indexeddbProvider.whenSynced.then(() => {
+  console.log('loaded data from indexed db')
+})
+
+// Sync clients with the y-webrtc provider.
+const webrtcProvider = new WebrtcProvider('count-demo', ydoc)
+
+// Sync clients with the y-websocket provider
+const websocketProvider = new WebsocketProvider(
+  'wss://demos.yjs.dev', 'count-demo', ydoc
+)
+
+// array of numbers which produce a sum
+const yarray = ydoc.getArray('count')
+
+// observe changes of the sum
+yarray.observe(event => {
+  // print updates when the data changes
+  console.log('new sum: ' + yarray.toArray().reduce((a,b) => a + b))
+})
+
+// add 1 to the sum
+yarray.push([1]) // => "new sum: 1"
+```
+
 ## API
 
 ```js
@@ -155,32 +261,38 @@ necessary.
   </p>
   <pre>const yarray = new Y.Array()</pre>
   <dl>
-    <b><code>insert(index:number, content:Array&lt;object|boolean|Array|string|number|Uint8Array|Y.Type&gt;)</code></b>
+    <b><code>parent:Y.AbstractType|null</code></b>
+    <dd></dd>
+    <b><code>insert(index:number, content:Array&lt;object|boolean|Array|string|number|null|Uint8Array|Y.Type&gt;)</code></b>
     <dd>
 Insert content at <var>index</var>. Note that content is an array of elements.
-I.e. <code>array.insert(0, [1]</code> splices the list and inserts 1 at
+I.e. <code>array.insert(0, [1])</code> splices the list and inserts 1 at
 position 0.
     </dd>
-    <b><code>push(Array&lt;Object|boolean|Array|string|number|Uint8Array|Y.Type&gt;)</code></b>
+    <b><code>push(Array&lt;Object|boolean|Array|string|number|null|Uint8Array|Y.Type&gt;)</code></b>
+    <dd></dd>
+    <b><code>unshift(Array&lt;Object|boolean|Array|string|number|null|Uint8Array|Y.Type&gt;)</code></b>
     <dd></dd>
     <b><code>delete(index:number, length:number)</code></b>
     <dd></dd>
     <b><code>get(index:number)</code></b>
     <dd></dd>
+    <b><code>slice(start:number, end:number):Array&lt;Object|boolean|Array|string|number|null|Uint8Array|Y.Type&gt;</code></b>
+    <dd>Retrieve a range of content</dd>
     <b><code>length:number</code></b>
     <dd></dd>
     <b>
       <code>
-forEach(function(value:object|boolean|Array|string|number|Uint8Array|Y.Type,
+forEach(function(value:object|boolean|Array|string|number|null|Uint8Array|Y.Type,
  index:number, array: Y.Array))
       </code>
     </b>
     <dd></dd>
     <b><code>map(function(T, number, YArray):M):Array&lt;M&gt;</code></b>
     <dd></dd>
-    <b><code>toArray():Array&lt;object|boolean|Array|string|number|Uint8Array|Y.Type&gt;</code></b>
+    <b><code>toArray():Array&lt;object|boolean|Array|string|number|null|Uint8Array|Y.Type&gt;</code></b>
     <dd>Copies the content of this YArray to a new Array.</dd>
-    <b><code>toJSON():Array&lt;Object|boolean|Array|string|number&gt;</code></b>
+    <b><code>toJSON():Array&lt;Object|boolean|Array|string|number|null&gt;</code></b>
     <dd>
 Copies the content of this YArray to a new Array. It transforms all child types
 to JSON using their <code>toJSON</code> method.
@@ -222,9 +334,13 @@ or any of its children.
   </p>
   <pre><code>const ymap = new Y.Map()</code></pre>
   <dl>
-    <b><code>get(key:string):object|boolean|string|number|Uint8Array|Y.Type</code></b>
+    <b><code>parent:Y.AbstractType|null</code></b>
     <dd></dd>
-    <b><code>set(key:string, value:object|boolean|string|number|Uint8Array|Y.Type)</code></b>
+    <b><code>size: number</code></b>
+    <dd>Total number of key/value pairs.</dd>
+    <b><code>get(key:string):object|boolean|string|number|null|Uint8Array|Y.Type</code></b>
+    <dd></dd>
+    <b><code>set(key:string, value:object|boolean|string|number|null|Uint8Array|Y.Type)</code></b>
     <dd></dd>
     <b><code>delete(key:string)</code></b>
     <dd></dd>
@@ -232,12 +348,16 @@ or any of its children.
     <dd></dd>
     <b><code>get(index:number)</code></b>
     <dd></dd>
-    <b><code>toJSON():Object&lt;string, Object|boolean|Array|string|number|Uint8Array&gt;</code></b>
+    <b><code>clear()</code></b>
+    <dd>Removes all elements from this YMap.</dd>
+    <b><code>clone():Y.Map</code></b>
+    <dd>Clone this type into a fresh Yjs type.</dd>
+    <b><code>toJSON():Object&lt;string, Object|boolean|Array|string|number|null|Uint8Array&gt;</code></b>
     <dd>
 Copies the <code>[key,value]</code> pairs of this YMap to a new Object.It
 transforms all child types to JSON using their <code>toJSON</code> method.
     </dd>
-    <b><code>forEach(function(value:object|boolean|Array|string|number|Uint8Array|Y.Type,
+    <b><code>forEach(function(value:object|boolean|Array|string|number|null|Uint8Array|Y.Type,
  key:string, map: Y.Map))</code></b>
     <dd>
       Execute the provided function once for every key-value pair.
@@ -299,6 +419,8 @@ YTextEvents compute changes as deltas.
   </p>
   <pre>const ytext = new Y.Text()</pre>
   <dl>
+    <b><code>parent:Y.AbstractType|null</code></b>
+    <dd></dd>
     <b><code>insert(index:number, content:string, [formattingAttributes:Object&lt;string,string&gt;])</code></b>
     <dd>
       Insert a string at <var>index</var> and assign formatting attributes to it.
@@ -308,8 +430,12 @@ YTextEvents compute changes as deltas.
     <dd></dd>
     <b><code>format(index:number, length:number, formattingAttributes:Object&lt;string,string&gt;)</code></b>
     <dd>Assign formatting attributes to a range in the text</dd>
-    <b><code>applyDelta(delta)</code></b>
-    <dd>See <a href="https://quilljs.com/docs/delta/">Quill Delta</a></dd>
+    <b><code>applyDelta(delta: Delta, opts:Object&lt;string,any&gt;)</code></b>
+    <dd>
+        See <a href="https://quilljs.com/docs/delta/">Quill Delta</a>
+        Can set options for preventing remove ending newLines, default is true.
+        <pre>ytext.applyDelta(delta, { sanitize: false })</pre>
+    </dd>
     <b><code>length:number</code></b>
     <dd></dd>
     <b><code>toString():string</code></b>
@@ -353,14 +479,22 @@ or any of its children.
   </p>
   <pre><code>const yxml = new Y.XmlFragment()</code></pre>
   <dl>
+    <b><code>parent:Y.AbstractType|null</code></b>
+    <dd></dd>
+    <b><code>firstChild:Y.XmlElement|Y.XmlText|null</code></b>
+    <dd></dd>
     <b><code>insert(index:number, content:Array&lt;Y.XmlElement|Y.XmlText&gt;)</code></b>
     <dd></dd>
     <b><code>delete(index:number, length:number)</code></b>
     <dd></dd>
     <b><code>get(index:number)</code></b>
     <dd></dd>
+    <b><code>slice(start:number, end:number):Array&lt;Y.XmlElement|Y.XmlText&gt;</code></b>
+    <dd>Retrieve a range of content</dd>
     <b><code>length:number</code></b>
     <dd></dd>
+    <b><code>clone():Y.XmlFragment</code></b>
+    <dd>Clone this type into a fresh Yjs type.</dd>
     <b><code>toArray():Array&lt;Y.XmlElement|Y.XmlText&gt;</code></b>
     <dd>Copies the children to a new Array.</dd>
     <b><code>toDOM():DocumentFragment</code></b>
@@ -369,6 +503,8 @@ or any of its children.
     <dd>Get the XML serialization of all descendants.</dd>
     <b><code>toJSON():string</code></b>
     <dd>See <code>toString</code>.</dd>
+    <b><code>createTreeWalker(filter: function(AbstractType&lt;any&gt;):boolean):Iterable</code></b>
+    <dd>Create an Iterable that walks through the children.</dd>
     <b><code>observe(function(YXmlEvent, Transaction):void)</code></b>
     <dd>
 Adds an event listener to this type that will be called synchronously every time
@@ -404,6 +540,14 @@ content and be actually XML compliant.
   </p>
   <pre><code>const yxml = new Y.XmlElement()</code></pre>
   <dl>
+    <b><code>parent:Y.AbstractType|null</code></b>
+    <dd></dd>
+    <b><code>firstChild:Y.XmlElement|Y.XmlText|null</code></b>
+    <dd></dd>
+    <b><code>nextSibling:Y.XmlElement|Y.XmlText|null</code></b>
+    <dd></dd>
+    <b><code>prevSibling:Y.XmlElement|Y.XmlText|null</code></b>
+    <dd></dd>
     <b><code>insert(index:number, content:Array&lt;Y.XmlElement|Y.XmlText&gt;)</code></b>
     <dd></dd>
     <b><code>delete(index:number, length:number)</code></b>
@@ -418,8 +562,14 @@ content and be actually XML compliant.
     <dd></dd>
     <b><code>getAttribute(attributeName:string):string</code></b>
     <dd></dd>
-    <b><code>getAttributes(attributeName:string):Object&lt;string,string&gt;</code></b>
+    <b><code>getAttributes():Object&lt;string,string&gt;</code></b>
     <dd></dd>
+    <b><code>get(i:number):Y.XmlElement|Y.XmlText</code></b>
+    <dd>Retrieve the i-th element.</dd>
+    <b><code>slice(start:number, end:number):Array&lt;Y.XmlElement|Y.XmlText&gt;</code></b>
+    <dd>Retrieve a range of content</dd>
+    <b><code>clone():Y.XmlElement</code></b>
+    <dd>Clone this type into a fresh Yjs type.</dd>
     <b><code>toArray():Array&lt;Y.XmlElement|Y.XmlText&gt;</code></b>
     <dd>Copies the children to a new Array.</dd>
     <b><code>toDOM():Element</code></b>
@@ -478,6 +628,13 @@ calls. I.e. <code>doc.transact(() => { yarray.insert(..); ymap.set(..) })</code>
 triggers a single change event. <br>You can specify an optional <code>origin</code>
 parameter that is stored on <code>transaction.origin</code> and
 <code>on('update', (update, origin) => ..)</code>.
+  </dd>
+  <b><code>toJSON():any</code></b>
+  <dd>
+Deprecated: It is recommended to call toJSON directly on the shared types.
+Converts the entire document into a js object, recursively traversing each yjs
+type. Doesn't log types that have not been defined (using
+<code>ydoc.getType(..)</code>).
   </dd>
   <b><code>get(string, Y.[TypeClass]):[Type]</code></b>
   <dd>Define a shared type.</dd>
@@ -485,6 +642,8 @@ parameter that is stored on <code>transaction.origin</code> and
   <dd>Define a shared Y.Array type. Is equivalent to <code>y.get(string, Y.Array)</code>.</dd>
   <b><code>getMap(string):Y.Map</code></b>
   <dd>Define a shared Y.Map type. Is equivalent to <code>y.get(string, Y.Map)</code>.</dd>
+  <b><code>getText(string):Y.Text</code></b>
+  <dd>Define a shared Y.Text type. Is equivalent to <code>y.get(string, Y.Text)</code>.</dd>
   <b><code>getXmlFragment(string):Y.XmlFragment</code></b>
   <dd>Define a shared Y.XmlFragment type. Is equivalent to <code>y.get(string, Y.XmlFragment)</code>.</dd>
   <b><code>on(string, function)</code></b>
@@ -505,6 +664,13 @@ peers. You can apply document updates in any order and multiple times.
   <dd>Emitted before each transaction.</dd>
   <b><code>on('afterTransaction', function(Y.Transaction, Y.Doc):void)</code></b>
   <dd>Emitted after each transaction.</dd>
+  <b><code>on('beforeAllTransactions', function(Y.Doc):void)</code></b>
+  <dd>
+Transactions can be nested (e.g. when an event within a transaction calls another
+transaction). Emitted before the first transaction.
+  </dd>
+  <b><code>on('afterAllTransactions', function(Y.Doc, Array&lt;Y.Transaction&gt;):void)</code></b>
+  <dd>Emitted after the last transaction is cleaned up.</dd>
 </dl>
 
 ### Document Updates
@@ -552,7 +718,7 @@ Y.applyUpdate(ydoc2, state1)
 This example shows how to sync two clients with the minimal amount of exchanged
 data by computing only the differences using the state vector of the remote
 client. Syncing clients using the state vector requires another roundtrip, but
-can safe a lot of bandwidth.
+can save a lot of bandwidth.
 
 ```js
 const stateVector1 = Y.encodeStateVector(ydoc1)
@@ -563,6 +729,41 @@ Y.applyUpdate(ydoc1, diff2)
 Y.applyUpdate(ydoc2, diff1)
 ```
 
+#### Example: Syncing clients without loading the Y.Doc
+
+It is possible to sync clients and compute delta updates without loading the Yjs
+document to memory. Yjs exposes an API to compute the differences directly on the
+binary document updates.
+
+```js
+// encode the current state as a binary buffer
+let currentState1 = Y.encodeStateAsUpdate(ydoc1)
+let currentState2 = Y.encodeStateAsUpdate(ydoc2)
+// now we can continue syncing clients using state vectors without using the Y.Doc
+ydoc1.destroy()
+ydoc2.destroy()
+
+const stateVector1 = Y.encodeStateVectorFromUpdate(currentState1)
+const stateVector2 = Y.encodeStateVectorFromUpdate(currentState2)
+const diff1 = Y.diffUpdate(currentState1, stateVector2)
+const diff2 = Y.diffUpdate(currentState2, stateVector1)
+
+// sync clients
+currentState1 = Y.mergeUpdates([currentState1, diff2])
+currentState1 = Y.mergeUpdates([currentState1, diff1])
+```
+
+#### Using V2 update format
+
+Yjs implements two update formats. By default you are using the V1 update format.
+You can opt-in into the V2 update format wich provides much better compression.
+It is not yet used by all providers. However, you can already use it if
+you are building your own provider. All below functions are available with the
+suffix "V2". E.g. `Y.applyUpdate` ⇒ `Y.applyUpdateV2`. We also support conversion
+functions between both formats: `Y.convertUpdateFormatV1ToV2` & `Y.convertUpdateFormatV2ToV1`.
+
+#### Update API
+
 <dl>
   <b><code>Y.applyUpdate(Y.Doc, update:Uint8Array, [transactionOrigin:any])</code></b>
   <dd>
@@ -579,21 +780,48 @@ differences to the update message.
   </dd>
   <b><code>Y.encodeStateVector(Y.Doc):Uint8Array</code></b>
   <dd>Computes the state vector and encodes it into an Uint8Array.</dd>
+  <b><code>Y.mergeUpdates(Array&lt;Uint8Array&gt;)</code></b>
+  <dd>
+Merge several document updates into a single document update while removing
+duplicate information. The merged document update is always smaller than
+the separate updates because of the compressed encoding.
+  </dd>
+  <b><code>Y.encodeStateVectorFromUpdate(Uint8Array): Uint8Array</code></b>
+  <dd>
+Computes the state vector from a document update and encodes it into an Uint8Array.
+  </dd>
+  <b><code>Y.diffUpdate(update: Uint8Array, stateVector: Uint8Array): Uint8Array</code></b>
+  <dd>
+Encode the missing differences to another update message. This function works
+similarly to <code>Y.encodeStateAsUpdate(ydoc, stateVector)</code> but works
+on updates instead.
+  </dd>
+  <b><code>convertUpdateFormatV1ToV2</code></b>
+  <dd>
+Convert V1 update format to the V2 update format.
+  </dd>
+  <b><code>convertUpdateFormatV2ToV1</code></b>
+  <dd>
+Convert V2 update format to the V1 update format.
+  </dd>
 </dl>
 
 ### Relative Positions
 
-> This API is not stable yet
+When working with collaborative documents, we often need to work with positions.
+Positions may represent cursor locations, selection ranges, or even assign a
+comment to a range of text. Normal index-positions (expressed as integers) are
+not convenient to use because the index-range is invalidated as soon as a remote
+change manipulates the document. Relative positions give you a powerful API to
+express positions.
 
-This feature is intended for managing selections / cursors. When working with
-other users that manipulate the shared document, you can't trust that an index
-position (an integer) will stay at the intended location. A *relative position*
-is fixated to an element in the shared document and is not affected by remote
-changes. I.e. given the document `"a|c"`, the relative position is attached to
-`c`. When a remote user modifies the document by inserting a character before
-the cursor, the cursor will stay attached to the character `c`. `insert(1,
-'x')("a|c") = "ax|c"`. When the *relative position* is set to the end of the
-document, it will stay attached to the end of the document.
+A relative position is fixated to an element in the shared document and is not
+affected by remote changes. I.e. given the document `"a|c"`, the relative
+position is attached to `c`. When a remote user modifies the document by
+inserting a character before the cursor, the cursor will stay attached to the
+character `c`. `insert(1, 'x')("a|c") = "ax|c"`. When the relative position is
+set to the end of the document, it will stay attached to the end of the
+document.
 
 #### Example: Transform to RelativePosition and back
 
@@ -629,23 +857,44 @@ pos.index === 2 // => true
 ```
 
 <dl>
-  <b><code>Y.createRelativePositionFromTypeIndex(Uint8Array|Y.Type, number)</code></b>
-  <dd></dd>
-  <b><code>Y.createAbsolutePositionFromRelativePosition(RelativePosition, Y.Doc)</code></b>
-  <dd></dd>
-  <b><code>Y.encodeRelativePosition(RelativePosition):Uint8Array</code></b>
-  <dd></dd>
+  <b><code>
+Y.createRelativePositionFromTypeIndex(type:Uint8Array|Y.Type, index: number
+[, assoc=0])
+  </code></b>
+  <dd>
+Create a relative position fixated to the i-th element in any sequence-like
+shared type (if <code>assoc >= 0</code>). By default, the position associates
+with the character that comes after the specified index position. If
+<code>assoc < 0</code>, then the relative position associates with the character
+before the specified index position.
+  </dd>
+  <b><code>
+Y.createAbsolutePositionFromRelativePosition(RelativePosition, Y.Doc):
+{ type: Y.AbstractType, index: number, assoc: number } | null
+  </code></b>
+  <dd>
+Create an absolute position from a relative position. If the relative position
+cannot be referenced, or the type is deleted, then the result is null.
+  </dd>
+  <b><code>
+Y.encodeRelativePosition(RelativePosition):Uint8Array
+  </code></b>
+  <dd>
+Encode a relative position to an Uint8Array. Binary data is the preferred
+encoding format for document updates. If you prefer JSON encoding, you can
+simply JSON.stringify / JSON.parse the relative position instead.
+  </dd>
   <b><code>Y.decodeRelativePosition(Uint8Array):RelativePosition</code></b>
-  <dd></dd>
+  <dd>Decode a binary-encoded relative position to a RelativePositon object.</dd>
 </dl>
 
 ### Y.UndoManager
 
-Yjs ships with an Undo/Redo manager for selective undo/redo of of changes on a
+Yjs ships with an Undo/Redo manager for selective undo/redo of changes on a
 Yjs type. The changes can be optionally scoped to transaction origins.
 
 ```js
-const ytext = doc.getArray('array')
+const ytext = doc.getText('text')
 const undoManager = new Y.UndoManager(ytext)
 
 ytext.insert(0, 'abc')
@@ -677,6 +926,16 @@ undo- or the redo-stack.
   </dd>
   <b>
     <code>
+on('stack-item-updated', { stackItem: { meta: Map&lt;any,any&gt; }, type: 'undo'
+| 'redo' })
+    </code>
+  </b>
+  <dd>
+Register an event that is called when an existing <code>StackItem</code> is updated.
+This happens when two changes happen within a "captureInterval".
+  </dd>
+  <b>
+    <code>
 on('stack-item-popped', { stackItem: { meta: Map&lt;any,any&gt; }, type: 'undo'
 | 'redo' })
     </code>
@@ -685,6 +944,14 @@ on('stack-item-popped', { stackItem: { meta: Map&lt;any,any&gt; }, type: 'undo'
 Register an event that is called when a <code>StackItem</code> is popped from
 the undo- or the redo-stack.
   </dd>
+  <b>
+    <code>
+on('stack-cleared', { undoStackCleared: boolean, redoStackCleared: boolean })
+    </code>
+  </b>
+  <dd>
+Register an event that is called when the undo- and/or the redo-stack is cleared.
+  </dd>
 </dl>
 
 #### Example: Stop Capturing
@@ -717,7 +984,7 @@ UndoManager instance is always added to `trackedOrigins`.
 ```js
 class CustomBinding {}
 
-const ytext = doc.getArray('array')
+const ytext = doc.getText('text')
 const undoManager = new Y.UndoManager(ytext, {
   trackedOrigins: new Set([42, CustomBinding])
 })
@@ -757,7 +1024,7 @@ additional meta information like the cursor location or the view on the
 document. You can assign meta-information to Undo-/Redo-StackItems.
 
 ```js
-const ytext = doc.getArray('array')
+const ytext = doc.getText('text')
 const undoManager = new Y.UndoManager(ytext, {
   trackedOrigins: new Set([42, CustomBinding])
 })
@@ -773,29 +1040,11 @@ undoManager.on('stack-item-popped', event => {
 })
 ```
 
-## Miscellaneous
-
-### Typescript Declarations
-
-Yjs has type descriptions. But until [this
-ticket](https://github.com/Microsoft/TypeScript/issues/7546) is fixed, this is
-how you can make use of Yjs type declarations.
-
-```json
-{
-  "compilerOptions": {
-    "allowJs": true,
-    "checkJs": true,
-  },
-  "maxNodeModuleJsDepth": 5
-}
-```
-
 ## Yjs CRDT Algorithm
 
 *Conflict-free replicated data types* (CRDT) for collaborative editing are an
 alternative approach to *operational transformation* (OT). A very simple
-differenciation between the two approaches is that OT attempts to transform
+differentiation between the two approaches is that OT attempts to transform
 index positions to ensure convergence (all clients end up with the same
 content), while CRDTs use mathematical models that usually do not involve index
 transformations, like linked lists. OT is currently the de-facto standard for
@@ -807,25 +1056,29 @@ do not require a central source of truth.
 
 Yjs implements a modified version of the algorithm described in [this
 paper](https://www.researchgate.net/publication/310212186_Near_Real-Time_Peer-to-Peer_Shared_Editing_on_Extensible_Data_Types).
-I will eventually publish a paper that describes why this approach works so well
-in practice. Note: Since operations make up the document structure, we prefer
-the term *struct* now.
+This [article](https://blog.kevinjahns.de/are-crdts-suitable-for-shared-editing/)
+explains a simple optimization on the CRDT model and
+gives more insight about the performance characteristics in Yjs.
+More information about the specific implementation is available in
+[INTERNALS.md](./INTERNALS.md) and in
+[this walkthrough of the Yjs codebase](https://youtu.be/0l5XgnQ6rB4).
 
-CRDTs suitable for shared text editing suffer from the fact that they only grow
-in size. There are CRDTs that do not grow in size, but they do not have the
-characteristics that are benificial for shared text editing (like intention
-preservation). Yjs implements many improvements to the original algorithm that
-diminish the trade-off that the document only grows in size. We can't garbage
-collect deleted structs (tombstones) while ensuring a unique order of the
-structs. But we can 1. merge preceeding structs into a single struct to reduce
-the amount of meta information, 2. we can delete content from the struct if it
-is deleted, and 3. we can garbage collect tombstones if we don't care about the
-order of the structs anymore (e.g. if the parent was deleted).
+CRDTs that are suitable for shared text editing suffer from the fact that they
+only grow in size. There are CRDTs that do not grow in size, but they do not
+have the characteristics that are benificial for shared text editing (like
+intention preservation). Yjs implements many improvements to the original
+algorithm that diminish the trade-off that the document only grows in size. We
+can't garbage collect deleted structs (tombstones) while ensuring a unique
+order of the structs. But we can 1. merge preceeding structs into a single
+struct to reduce the amount of meta information, 2. we can delete content from
+the struct if it is deleted, and 3. we can garbage collect tombstones if we
+don't care about the order of the structs anymore (e.g. if the parent was
+deleted).
 
 **Examples:**
 
 1. If a user inserts elements in sequence, the struct will be merged into a
-   single struct. E.g. `array.insert(0, ['a']), array.insert(0, ['b']);` is
+   single struct. E.g. `text.insert(0, 'a'), text.insert(1, 'b');` is
    first represented as two structs (`[{id: {client, clock: 0}, content: 'a'},
    {id: {client, clock: 1}, content: 'b'}`) and then merged into a single
    struct: `[{id: {client, clock: 0}, content: 'ab'}]`.
@@ -864,5 +1117,6 @@ Yjs and all related projects are [**MIT licensed**](./LICENSE).
 Yjs is based on my research as a student at the [RWTH
 i5](http://dbis.rwth-aachen.de/). Now I am working on Yjs in my spare time.
 
-Fund this project by donating on [Patreon](https://www.patreon.com/dmonad) or
-hiring [me](https://github.com/dmonad) for professional support.
+Fund this project by donating on [GitHub Sponsors](https://github.com/sponsors/dmonad)
+or hiring [me](https://github.com/dmonad) as a contractor for your collaborative
+app.

package.json

@@ -1,32 +1,50 @@
 {
   "name": "yjs",
-  "version": "13.0.7",
+  "version": "13.5.47",
   "description": "Shared Editing Library",
   "main": "./dist/yjs.cjs",
   "module": "./dist/yjs.mjs",
   "types": "./dist/src/index.d.ts",
+  "type": "module",
   "sideEffects": false,
+  "funding": {
+    "type": "GitHub Sponsors ❤",
+    "url": "https://github.com/sponsors/dmonad"
+  },
   "scripts": {
-    "test": "npm run dist && node ./dist/tests.cjs --repitition-time 50",
-    "test-extensive": "npm run lint && npm run dist && node ./dist/tests.cjs --production --repitition-time 10000",
+    "test": "npm run dist && node ./dist/tests.cjs --repetition-time 50",
+    "test-extensive": "npm run lint && npm run dist && node ./dist/tests.cjs --production --repetition-time 10000",
     "dist": "rm -rf dist && rollup -c && tsc",
     "watch": "rollup -wc",
     "lint": "markdownlint README.md && standard && tsc",
     "docs": "rm -rf docs; jsdoc --configure ./.jsdoc.json --verbose --readme ./README.md --package ./package.json || true",
     "serve-docs": "npm run docs && http-server ./docs/",
-    "preversion": "npm run lint && PRODUCTION=1 npm run dist && npm run docs && node ./dist/tests.cjs --repitition-time 1000",
+    "preversion": "npm run lint && PRODUCTION=1 npm run dist && npm run docs && node ./dist/tests.cjs --repetition-time 1000 && test -e dist/src/index.d.ts && test -e dist/yjs.cjs && test -e dist/yjs.cjs",
     "debug": "concurrently 'http-server -o test.html' 'npm run watch'",
     "trace-deopt": "clear && rollup -c  && node --trace-deopt dist/test.cjs",
     "trace-opt": "clear && rollup -c  && node --trace-opt dist/test.cjs"
   },
+  "exports": {
+    ".": {
+      "types": "./dist/src/index.d.ts",
+      "module": "./dist/yjs.mjs",
+      "import": "./dist/yjs.mjs",
+      "require": "./dist/yjs.cjs"
+    },
+    "./src/index.js": "./src/index.js",
+    "./tests/testHelper.js": "./tests/testHelper.js",
+    "./testHelper": "./dist/testHelper.mjs",
+    "./package.json": "./package.json"
+  },
   "files": [
-    "dist/*",
-    "src/*",
-    "tests/*",
-    "docs/*"
+    "dist/yjs.*",
+    "dist/src",
+    "src",
+    "tests/testHelper.js",
+    "dist/testHelper.mjs",
+    "sponsor-y.js"
   ],
   "dictionaries": {
-    "doc": "docs",
     "test": "tests"
   },
   "standard": {
@@ -44,7 +62,8 @@
     "Yjs",
     "CRDT",
     "offline",
-    "shared editing",
+    "offline-first",
+    "shared-editing",
     "concurrency",
     "collaboration"
   ],
@@ -54,22 +73,21 @@
   "bugs": {
     "url": "https://github.com/yjs/yjs/issues"
   },
-  "homepage": "https://yjs.dev",
+  "homepage": "https://docs.yjs.dev",
   "dependencies": {
-    "lib0": "^0.2.26"
+    "lib0": "^0.2.49"
   },
   "devDependencies": {
-    "@rollup/plugin-commonjs": "^11.0.1",
-    "@rollup/plugin-node-resolve": "^7.0.0",
+    "@rollup/plugin-commonjs": "^17.0.0",
+    "@rollup/plugin-node-resolve": "^11.2.1",
     "concurrently": "^3.6.1",
-    "http-server": "^0.12.1",
-    "jsdoc": "^3.6.3",
-    "markdownlint-cli": "^0.19.0",
-    "rollup": "^1.30.0",
-    "rollup-cli": "^1.0.9",
-    "standard": "^14.0.0",
+    "typescript": "^4.9.5",
+    "http-server": "^0.12.3",
+    "jsdoc": "^3.6.7",
+    "markdownlint-cli": "^0.23.2",
+    "rollup": "^2.60.0",
+    "standard": "^16.0.4",
     "tui-jsdoc-template": "^1.2.2",
-    "typescript": "^3.7.5",
-    "y-protocols": "^0.2.3"
+    "y-protocols": "^1.0.5"
   }
 }

rollup.config.js

@@ -45,7 +45,7 @@ export default [{
     sourcemap: true,
     paths: path => {
       if (/^lib0\//.test(path)) {
-        return `lib0/dist/${path.slice(5, -3)}.cjs`
+        return `lib0/dist/${path.slice(5)}.cjs`
       }
       return path
     }
@@ -60,6 +60,23 @@ export default [{
     sourcemap: true
   },
   external: id => /^lib0\//.test(id)
+}, {
+  input: './tests/testHelper.js',
+  output: {
+    name: 'Y',
+    file: 'dist/testHelper.mjs',
+    format: 'esm',
+    sourcemap: true
+  },
+  external: id => /^lib0\//.test(id) || id === 'yjs',
+  plugins: [{
+    resolveId (importee) {
+      if (importee === '../src/index.js') {
+        return 'yjs'
+      }
+      return null
+    }
+  }]
 }, {
   input: './tests/index.js',
   output: {

src/index.js

@@ -1,3 +1,4 @@
+/** eslint-env browser */
 
 export {
   Doc,
@@ -12,6 +13,7 @@ export {
   YXmlEvent,
   YMapEvent,
   YArrayEvent,
+  YTextEvent,
   YEvent,
   Item,
   AbstractStruct,
@@ -25,14 +27,13 @@ export {
   ContentString,
   ContentType,
   AbstractType,
-  RelativePosition,
   getTypeChildren,
   createRelativePositionFromTypeIndex,
   createRelativePositionFromJSON,
   createAbsolutePositionFromRelativePosition,
   compareRelativePositions,
-  writeRelativePosition,
-  readRelativePosition,
+  AbsolutePosition,
+  RelativePosition,
   ID,
   createID,
   compareIDs,
@@ -41,23 +42,81 @@ export {
   createSnapshot,
   createDeleteSet,
   createDeleteSetFromStructStore,
+  cleanupYTextFormatting,
   snapshot,
   emptySnapshot,
   findRootTypeKey,
+  findIndexSS,
+  getItem,
   typeListToArraySnapshot,
   typeMapGetSnapshot,
+  createDocFromSnapshot,
   iterateDeletedStructs,
   applyUpdate,
+  applyUpdateV2,
   readUpdate,
+  readUpdateV2,
   encodeStateAsUpdate,
+  encodeStateAsUpdateV2,
   encodeStateVector,
   UndoManager,
   decodeSnapshot,
   encodeSnapshot,
+  decodeSnapshotV2,
+  encodeSnapshotV2,
+  decodeStateVector,
+  logUpdate,
+  logUpdateV2,
+  decodeUpdate,
+  decodeUpdateV2,
+  relativePositionToJSON,
   isDeleted,
   isParentOf,
   equalSnapshots,
   PermanentUserData, // @TODO experimental
   tryGc,
-  transact
+  transact,
+  AbstractConnector,
+  logType,
+  mergeUpdates,
+  mergeUpdatesV2,
+  parseUpdateMeta,
+  parseUpdateMetaV2,
+  encodeStateVectorFromUpdate,
+  encodeStateVectorFromUpdateV2,
+  encodeRelativePosition,
+  decodeRelativePosition,
+  diffUpdate,
+  diffUpdateV2,
+  convertUpdateFormatV1ToV2,
+  convertUpdateFormatV2ToV1,
+  UpdateEncoderV1
 } from './internals.js'
+
+const glo = /** @type {any} */ (typeof globalThis !== 'undefined'
+  ? globalThis
+  : typeof window !== 'undefined'
+    ? window
+    // @ts-ignore
+    : typeof global !== 'undefined' ? global : {})
+
+const importIdentifier = '__ $YJS$ __'
+
+if (glo[importIdentifier] === true) {
+  /**
+   * Dear reader of this message. Please take this seriously.
+   *
+   * If you see this message, make sure that you only import one version of Yjs. In many cases,
+   * your package manager installs two versions of Yjs that are used by different packages within your project.
+   * Another reason for this message is that some parts of your project use the commonjs version of Yjs
+   * and others use the EcmaScript version of Yjs.
+   *
+   * This often leads to issues that are hard to debug. We often need to perform constructor checks,
+   * e.g. `struct instanceof GC`. If you imported different versions of Yjs, it is impossible for us to
+   * do the constructor checks anymore - which might break the CRDT algorithm.
+   *
+   * https://github.com/yjs/yjs/issues/438
+   */
+  console.error('Yjs was already imported. This breaks constructor checks and will lead to issues! - https://github.com/yjs/yjs/issues/438')
+}
+glo[importIdentifier] = true

src/internals.js

@@ -1,16 +1,21 @@
 
+export * from './utils/AbstractConnector.js'
 export * from './utils/DeleteSet.js'
 export * from './utils/Doc.js'
+export * from './utils/UpdateDecoder.js'
+export * from './utils/UpdateEncoder.js'
 export * from './utils/encoding.js'
 export * from './utils/EventHandler.js'
 export * from './utils/ID.js'
 export * from './utils/isParentOf.js'
+export * from './utils/logging.js'
 export * from './utils/PermanentUserData.js'
 export * from './utils/RelativePosition.js'
 export * from './utils/Snapshot.js'
 export * from './utils/StructStore.js'
 export * from './utils/Transaction.js'
 export * from './utils/UndoManager.js'
+export * from './utils/updates.js'
 export * from './utils/YEvent.js'
 
 export * from './types/AbstractType.js'
@@ -27,6 +32,7 @@ export * from './structs/AbstractStruct.js'
 export * from './structs/GC.js'
 export * from './structs/ContentBinary.js'
 export * from './structs/ContentDeleted.js'
+export * from './structs/ContentDoc.js'
 export * from './structs/ContentEmbed.js'
 export * from './structs/ContentFormat.js'
 export * from './structs/ContentJSON.js'
@@ -34,3 +40,4 @@ export * from './structs/ContentAny.js'
 export * from './structs/ContentString.js'
 export * from './structs/ContentType.js'
 export * from './structs/Item.js'
+export * from './structs/Skip.js'

src/structs/AbstractStruct.js

@@ -1,10 +1,9 @@
 
 import {
-  StructStore, ID, Transaction // eslint-disable-line
+  UpdateEncoderV1, UpdateEncoderV2, ID, Transaction // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js' // eslint-disable-line
-import * as error from 'lib0/error.js'
+import * as error from 'lib0/error'
 
 export class AbstractStruct {
   /**
@@ -12,14 +11,15 @@ export class AbstractStruct {
    * @param {number} length
    */
   constructor (id, length) {
-    /**
-     * The uniqe identifier of this struct.
-     * @type {ID}
-     * @readonly
-     */
     this.id = id
     this.length = length
-    this.deleted = false
+  }
+
+  /**
+   * @type {boolean}
+   */
+  get deleted () {
+    throw error.methodUnimplemented()
   }
 
   /**
@@ -34,7 +34,7 @@ export class AbstractStruct {
   }
 
   /**
-   * @param {encoding.Encoder} encoder The encoder to write data to.
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
    * @param {number} offset
    * @param {number} encodingRef
    */
@@ -44,43 +44,9 @@ export class AbstractStruct {
 
   /**
    * @param {Transaction} transaction
-   */
-  integrate (transaction) {
-    throw error.methodUnimplemented()
-  }
-}
-
-export class AbstractStructRef {
-  /**
-   * @param {ID} id
-   */
-  constructor (id) {
-    /**
-     * @type {Array<ID>}
-     */
-    this._missing = []
-    /**
-     * The uniqe identifier of this type.
-     * @type {ID}
-     */
-    this.id = id
-  }
-
-  /**
-   * @param {Transaction} transaction
-   * @return {Array<ID|null>}
-   */
-  getMissing (transaction) {
-    return this._missing
-  }
-
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
    * @param {number} offset
-   * @return {AbstractStruct}
    */
-  toStruct (transaction, store, offset) {
+  integrate (transaction, offset) {
     throw error.methodUnimplemented()
   }
 }

src/structs/ContentAny.js

@@ -1,10 +1,7 @@
 import {
-  Transaction, Item, StructStore // eslint-disable-line
+  UpdateEncoderV1, UpdateEncoderV2, UpdateDecoderV1, UpdateDecoderV2, Transaction, Item, StructStore // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
 export class ContentAny {
   /**
    * @param {Array<any>} arr
@@ -77,15 +74,15 @@ export class ContentAny {
    */
   gc (store) {}
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
     const len = this.arr.length
-    encoding.writeVarUint(encoder, len - offset)
+    encoder.writeLen(len - offset)
     for (let i = offset; i < len; i++) {
       const c = this.arr[i]
-      encoding.writeAny(encoder, c)
+      encoder.writeAny(c)
     }
   }
 
@@ -98,14 +95,14 @@ export class ContentAny {
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {ContentAny}
  */
 export const readContentAny = decoder => {
-  const len = decoding.readVarUint(decoder)
+  const len = decoder.readLen()
   const cs = []
   for (let i = 0; i < len; i++) {
-    cs.push(decoding.readAny(decoder))
+    cs.push(decoder.readAny())
   }
   return new ContentAny(cs)
 }

src/structs/ContentBinary.js

@@ -1,11 +1,8 @@
 import {
-  StructStore, Item, Transaction // eslint-disable-line
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, StructStore, Item, Transaction // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-import * as buffer from 'lib0/buffer.js'
-import * as error from 'lib0/error.js'
+import * as error from 'lib0/error'
 
 export class ContentBinary {
   /**
@@ -73,11 +70,11 @@ export class ContentBinary {
    */
   gc (store) {}
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
-    encoding.writeVarUint8Array(encoder, this.content)
+    encoder.writeBuf(this.content)
   }
 
   /**
@@ -89,7 +86,7 @@ export class ContentBinary {
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2 } decoder
  * @return {ContentBinary}
  */
-export const readContentBinary = decoder => new ContentBinary(buffer.copyUint8Array(decoding.readVarUint8Array(decoder)))
+export const readContentBinary = decoder => new ContentBinary(decoder.readBuf())

src/structs/ContentDeleted.js

@@ -1,12 +1,9 @@
 
 import {
   addToDeleteSet,
-  StructStore, Item, Transaction // eslint-disable-line
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, StructStore, Item, Transaction // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
 export class ContentDeleted {
   /**
    * @param {number} len
@@ -67,8 +64,8 @@ export class ContentDeleted {
    * @param {Item} item
    */
   integrate (transaction, item) {
-    addToDeleteSet(transaction.deleteSet, item.id, this.len)
-    item.deleted = true
+    addToDeleteSet(transaction.deleteSet, item.id.client, item.id.clock, this.len)
+    item.markDeleted()
   }
 
   /**
@@ -80,11 +77,11 @@ export class ContentDeleted {
    */
   gc (store) {}
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
-    encoding.writeVarUint(encoder, this.len - offset)
+    encoder.writeLen(this.len - offset)
   }
 
   /**
@@ -98,7 +95,7 @@ export class ContentDeleted {
 /**
  * @private
  *
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2 } decoder
  * @return {ContentDeleted}
  */
-export const readContentDeleted = decoder => new ContentDeleted(decoding.readVarUint(decoder))
+export const readContentDeleted = decoder => new ContentDeleted(decoder.readLen())

src/structs/ContentDoc.js

@@ -0,0 +1,141 @@
+
+import {
+  Doc, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, StructStore, Transaction, Item // eslint-disable-line
+} from '../internals.js'
+
+import * as error from 'lib0/error'
+
+/**
+ * @param {string} guid
+ * @param {Object<string, any>} opts
+ */
+const createDocFromOpts = (guid, opts) => new Doc({ guid, ...opts, shouldLoad: opts.shouldLoad || opts.autoLoad || false })
+
+/**
+ * @private
+ */
+export class ContentDoc {
+  /**
+   * @param {Doc} doc
+   */
+  constructor (doc) {
+    if (doc._item) {
+      console.error('This document was already integrated as a sub-document. You should create a second instance instead with the same guid.')
+    }
+    /**
+     * @type {Doc}
+     */
+    this.doc = doc
+    /**
+     * @type {any}
+     */
+    const opts = {}
+    this.opts = opts
+    if (!doc.gc) {
+      opts.gc = false
+    }
+    if (doc.autoLoad) {
+      opts.autoLoad = true
+    }
+    if (doc.meta !== null) {
+      opts.meta = doc.meta
+    }
+  }
+
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return 1
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return [this.doc]
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+
+  /**
+   * @return {ContentDoc}
+   */
+  copy () {
+    return new ContentDoc(createDocFromOpts(this.doc.guid, this.opts))
+  }
+
+  /**
+   * @param {number} offset
+   * @return {ContentDoc}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {ContentDoc} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    return false
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {
+    // this needs to be reflected in doc.destroy as well
+    this.doc._item = item
+    transaction.subdocsAdded.add(this.doc)
+    if (this.doc.shouldLoad) {
+      transaction.subdocsLoaded.add(this.doc)
+    }
+  }
+
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {
+    if (transaction.subdocsAdded.has(this.doc)) {
+      transaction.subdocsAdded.delete(this.doc)
+    } else {
+      transaction.subdocsRemoved.add(this.doc)
+    }
+  }
+
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) { }
+
+  /**
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoder.writeString(this.doc.guid)
+    encoder.writeAny(this.opts)
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 9
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
+ * @return {ContentDoc}
+ */
+export const readContentDoc = decoder => new ContentDoc(createDocFromOpts(decoder.readString(), decoder.readAny()))

src/structs/ContentEmbed.js

@@ -1,11 +1,9 @@
 
 import {
-  StructStore, Item, Transaction // eslint-disable-line
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, StructStore, Item, Transaction // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-import * as error from 'lib0/error.js'
+import * as error from 'lib0/error'
 
 /**
  * @private
@@ -76,11 +74,11 @@ export class ContentEmbed {
    */
   gc (store) {}
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
-    encoding.writeVarString(encoder, JSON.stringify(this.embed))
+    encoder.writeJSON(this.embed)
   }
 
   /**
@@ -94,7 +92,7 @@ export class ContentEmbed {
 /**
  * @private
  *
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {ContentEmbed}
  */
-export const readContentEmbed = decoder => new ContentEmbed(JSON.parse(decoding.readVarString(decoder)))
+export const readContentEmbed = decoder => new ContentEmbed(decoder.readJSON())

src/structs/ContentFormat.js

@@ -1,11 +1,9 @@
 
 import {
-  Item, StructStore, Transaction // eslint-disable-line
+  AbstractType, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, Item, StructStore, Transaction // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-import * as error from 'lib0/error.js'
+import * as error from 'lib0/error'
 
 /**
  * @private
@@ -68,7 +66,11 @@ export class ContentFormat {
    * @param {Transaction} transaction
    * @param {Item} item
    */
-  integrate (transaction, item) {}
+  integrate (transaction, item) {
+    // @todo searchmarker are currently unsupported for rich text documents
+    /** @type {AbstractType<any>} */ (item.parent)._searchMarker = null
+  }
+
   /**
    * @param {Transaction} transaction
    */
@@ -78,12 +80,12 @@ export class ContentFormat {
    */
   gc (store) {}
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
-    encoding.writeVarString(encoder, this.key)
-    encoding.writeVarString(encoder, JSON.stringify(this.value))
+    encoder.writeKey(this.key)
+    encoder.writeJSON(this.value)
   }
 
   /**
@@ -95,7 +97,7 @@ export class ContentFormat {
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {ContentFormat}
  */
-export const readContentFormat = decoder => new ContentFormat(decoding.readVarString(decoder), JSON.parse(decoding.readVarString(decoder)))
+export const readContentFormat = decoder => new ContentFormat(decoder.readKey(), decoder.readJSON())

src/structs/ContentJSON.js

@@ -1,10 +1,7 @@
 import {
-  Transaction, Item, StructStore // eslint-disable-line
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, Transaction, Item, StructStore // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
 /**
  * @private
  */
@@ -80,15 +77,15 @@ export class ContentJSON {
    */
   gc (store) {}
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
     const len = this.arr.length
-    encoding.writeVarUint(encoder, len - offset)
+    encoder.writeLen(len - offset)
     for (let i = offset; i < len; i++) {
       const c = this.arr[i]
-      encoding.writeVarString(encoder, c === undefined ? 'undefined' : JSON.stringify(c))
+      encoder.writeString(c === undefined ? 'undefined' : JSON.stringify(c))
     }
   }
 
@@ -103,14 +100,14 @@ export class ContentJSON {
 /**
  * @private
  *
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {ContentJSON}
  */
 export const readContentJSON = decoder => {
-  const len = decoding.readVarUint(decoder)
+  const len = decoder.readLen()
   const cs = []
   for (let i = 0; i < len; i++) {
-    const c = decoding.readVarString(decoder)
+    const c = decoder.readString()
     if (c === 'undefined') {
       cs.push(undefined)
     } else {

src/structs/ContentString.js

@@ -1,10 +1,7 @@
 import {
-  Transaction, Item, StructStore // eslint-disable-line
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, Transaction, Item, StructStore // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
 /**
  * @private
  */
@@ -54,6 +51,17 @@ export class ContentString {
   splice (offset) {
     const right = new ContentString(this.str.slice(offset))
     this.str = this.str.slice(0, offset)
+
+    // Prevent encoding invalid documents because of splitting of surrogate pairs: https://github.com/yjs/yjs/issues/248
+    const firstCharCode = this.str.charCodeAt(offset - 1)
+    if (firstCharCode >= 0xD800 && firstCharCode <= 0xDBFF) {
+      // Last character of the left split is the start of a surrogate utf16/ucs2 pair.
+      // We don't support splitting of surrogate pairs because this may lead to invalid documents.
+      // Replace the invalid character with a unicode replacement character (<28> / U+FFFD)
+      this.str = this.str.slice(0, offset - 1) + '<27>'
+      // replace right as well
+      right.str = '<27>' + right.str.slice(1)
+    }
     return right
   }
 
@@ -80,11 +88,11 @@ export class ContentString {
    */
   gc (store) {}
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
-    encoding.writeVarString(encoder, offset === 0 ? this.str : this.str.slice(offset))
+    encoder.writeString(offset === 0 ? this.str : this.str.slice(offset))
   }
 
   /**
@@ -98,7 +106,7 @@ export class ContentString {
 /**
  * @private
  *
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {ContentString}
  */
-export const readContentString = decoder => new ContentString(decoding.readVarString(decoder))
+export const readContentString = decoder => new ContentString(decoder.readString())

src/structs/ContentType.js

@@ -7,15 +7,13 @@ import {
   readYXmlFragment,
   readYXmlHook,
   readYXmlText,
-  StructStore, Transaction, Item, YEvent, AbstractType // eslint-disable-line
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, StructStore, Transaction, Item, YEvent, AbstractType // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js' // eslint-disable-line
-import * as decoding from 'lib0/decoding.js'
-import * as error from 'lib0/error.js'
+import * as error from 'lib0/error'
 
 /**
- * @type {Array<function(decoding.Decoder):AbstractType<any>>}
+ * @type {Array<function(UpdateDecoderV1 | UpdateDecoderV2):AbstractType<any>>}
  * @private
  */
 export const typeRefs = [
@@ -41,7 +39,7 @@ export const YXmlTextRefID = 6
  */
 export class ContentType {
   /**
-   * @param {AbstractType<YEvent>} type
+   * @param {AbstractType<any>} type
    */
   constructor (type) {
     /**
@@ -111,11 +109,11 @@ export class ContentType {
       if (!item.deleted) {
         item.delete(transaction)
       } else {
-        // Whis will be gc'd later and we want to merge it if possible
+        // This will be gc'd later and we want to merge it if possible
         // We try to merge all deleted items after each transaction,
         // but we have no knowledge about that this needs to be merged
         // since it is not in transaction.ds. Hence we add it to transaction._mergeStructs
-        transaction._mergeStructs.add(item.id)
+        transaction._mergeStructs.push(item)
       }
       item = item.right
     }
@@ -124,7 +122,7 @@ export class ContentType {
         item.delete(transaction)
       } else {
         // same as above
-        transaction._mergeStructs.add(item.id)
+        transaction._mergeStructs.push(item)
       }
     })
     transaction.changed.delete(this.type)
@@ -150,7 +148,7 @@ export class ContentType {
   }
 
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
@@ -168,7 +166,7 @@ export class ContentType {
 /**
  * @private
  *
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {ContentType}
  */
-export const readContentType = decoder => new ContentType(typeRefs[decoding.readVarUint(decoder)](decoder))
+export const readContentType = decoder => new ContentType(typeRefs[decoder.readTypeRef()](decoder))

src/structs/GC.js

@@ -1,28 +1,18 @@
 
 import {
-  AbstractStructRef,
   AbstractStruct,
-  createID,
   addStruct,
-  StructStore, Transaction, ID // eslint-disable-line
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, StructStore, Transaction, ID // eslint-disable-line
 } from '../internals.js'
 
-import * as decoding from 'lib0/decoding.js'
-import * as encoding from 'lib0/encoding.js'
-
 export const structGCRefNumber = 0
 
 /**
  * @private
  */
 export class GC extends AbstractStruct {
-  /**
-   * @param {ID} id
-   * @param {number} length
-   */
-  constructor (id, length) {
-    super(id, length)
-    this.deleted = true
+  get deleted () {
+    return true
   }
 
   delete () {}
@@ -32,59 +22,40 @@ export class GC extends AbstractStruct {
    * @return {boolean}
    */
   mergeWith (right) {
+    if (this.constructor !== right.constructor) {
+      return false
+    }
     this.length += right.length
     return true
   }
 
   /**
    * @param {Transaction} transaction
+   * @param {number} offset
    */
-  integrate (transaction) {
+  integrate (transaction, offset) {
+    if (offset > 0) {
+      this.id.clock += offset
+      this.length -= offset
+    }
     addStruct(transaction.doc.store, this)
   }
 
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
-    encoding.writeUint8(encoder, structGCRefNumber)
-    encoding.writeVarUint(encoder, this.length - offset)
-  }
-}
-
-/**
- * @private
- */
-export class GCRef extends AbstractStructRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(id)
-    /**
-     * @type {number}
-     */
-    this.length = decoding.readVarUint(decoder)
+    encoder.writeInfo(structGCRefNumber)
+    encoder.writeLen(this.length - offset)
   }
 
   /**
    * @param {Transaction} transaction
    * @param {StructStore} store
-   * @param {number} offset
-   * @return {GC}
+   * @return {null | number}
    */
-  toStruct (transaction, store, offset) {
-    if (offset > 0) {
-      // @ts-ignore
-      this.id = createID(this.id.client, this.id.clock + offset)
-      this.length -= offset
-    }
-    return new GC(
-      this.id,
-      this.length
-    )
+  getMissing (transaction, store) {
+    return null
   }
 }

src/structs/Item.js

@@ -1,11 +1,7 @@
 
 import {
-  readID,
-  createID,
-  writeID,
   GC,
-  nextID,
-  AbstractStructRef,
+  getState,
   AbstractStruct,
   replaceStruct,
   addStruct,
@@ -21,18 +17,17 @@ import {
   readContentAny,
   readContentString,
   readContentEmbed,
+  readContentDoc,
+  createID,
   readContentFormat,
   readContentType,
   addChangedTypeToTransaction,
-  ContentType, ContentDeleted, StructStore, ID, AbstractType, Transaction // eslint-disable-line
+  isDeleted,
+  DeleteSet, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, ContentType, ContentDeleted, StructStore, ID, AbstractType, Transaction // eslint-disable-line
 } from '../internals.js'
 
-import * as error from 'lib0/error.js'
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-import * as maplib from 'lib0/map.js'
-import * as set from 'lib0/set.js'
-import * as binary from 'lib0/binary.js'
+import * as error from 'lib0/error'
+import * as binary from 'lib0/binary'
 
 /**
  * @todo This should return several items
@@ -73,7 +68,7 @@ export const followRedone = (store, id) => {
 export const keepItem = (item, keep) => {
   while (item !== null && item.keep !== keep) {
     item.keep = keep
-    item = item.parent._item
+    item = /** @type {AbstractType<any>} */ (item.parent)._item
   }
 }
 
@@ -88,12 +83,12 @@ export const keepItem = (item, keep) => {
  * @private
  */
 export const splitItem = (transaction, leftItem, diff) => {
-  const id = leftItem.id
   // create rightItem
+  const { client, clock } = leftItem.id
   const rightItem = new Item(
-    createID(id.client, id.clock + diff),
+    createID(client, clock + diff),
     leftItem,
-    createID(id.client, id.clock + diff - 1),
+    createID(client, clock + diff - 1),
     leftItem.right,
     leftItem.rightOrigin,
     leftItem.parent,
@@ -101,7 +96,7 @@ export const splitItem = (transaction, leftItem, diff) => {
     leftItem.content.splice(diff)
   )
   if (leftItem.deleted) {
-    rightItem.deleted = true
+    rightItem.markDeleted()
   }
   if (leftItem.keep) {
     rightItem.keep = true
@@ -116,10 +111,10 @@ export const splitItem = (transaction, leftItem, diff) => {
     rightItem.right.left = rightItem
   }
   // right is more specific.
-  transaction._mergeStructs.add(rightItem.id)
+  transaction._mergeStructs.push(rightItem)
   // update parent._map
   if (rightItem.parentSub !== null && rightItem.right === null) {
-    rightItem.parent._map.set(rightItem.parentSub, rightItem)
+    /** @type {AbstractType<any>} */ (rightItem.parent)._map.set(rightItem.parentSub, rightItem)
   }
   leftItem.length = diff
   return rightItem
@@ -131,55 +126,46 @@ export const splitItem = (transaction, leftItem, diff) => {
  * @param {Transaction} transaction The Yjs instance.
  * @param {Item} item
  * @param {Set<Item>} redoitems
+ * @param {DeleteSet} itemsToDelete
+ * @param {boolean} ignoreRemoteMapChanges
  *
  * @return {Item|null}
  *
  * @private
  */
-export const redoItem = (transaction, item, redoitems) => {
-  if (item.redone !== null) {
-    return getItemCleanStart(transaction, item.redone)
+export const redoItem = (transaction, item, redoitems, itemsToDelete, ignoreRemoteMapChanges) => {
+  const doc = transaction.doc
+  const store = doc.store
+  const ownClientID = doc.clientID
+  const redone = item.redone
+  if (redone !== null) {
+    return getItemCleanStart(transaction, redone)
   }
-  let parentItem = item.parent._item
+  let parentItem = /** @type {AbstractType<any>} */ (item.parent)._item
   /**
    * @type {Item|null}
    */
-  let left
+  let left = null
   /**
    * @type {Item|null}
    */
   let right
+  // make sure that parent is redone
+  if (parentItem !== null && parentItem.deleted === true) {
+    // try to undo parent if it will be undone anyway
+    if (parentItem.redone === null && (!redoitems.has(parentItem) || redoItem(transaction, parentItem, redoitems, itemsToDelete, ignoreRemoteMapChanges) === null)) {
+      return null
+    }
+    while (parentItem.redone !== null) {
+      parentItem = getItemCleanStart(transaction, parentItem.redone)
+    }
+  }
+  const parentType = parentItem === null ? /** @type {AbstractType<any>} */ (item.parent) : /** @type {ContentType} */ (parentItem.content).type
+
   if (item.parentSub === null) {
     // Is an array item. Insert at the old position
     left = item.left
     right = item
-  } else {
-    // Is a map item. Insert as current value
-    left = item
-    while (left.right !== null) {
-      left = left.right
-      if (left.id.client !== transaction.doc.clientID) {
-        // It is not possible to redo this item because it conflicts with a
-        // change from another client
-        return null
-      }
-    }
-    if (left.right !== null) {
-      left = /** @type {Item} */ (item.parent._map.get(item.parentSub))
-    }
-    right = null
-  }
-  // make sure that parent is redone
-  if (parentItem !== null && parentItem.deleted === true && parentItem.redone === null) {
-    // try to undo parent if it will be undone anyway
-    if (!redoitems.has(parentItem) || redoItem(transaction, parentItem, redoitems) === null) {
-      return null
-    }
-  }
-  if (parentItem !== null && parentItem.redone !== null) {
-    while (parentItem.redone !== null) {
-      parentItem = getItemCleanStart(transaction, parentItem.redone)
-    }
     // find next cloned_redo items
     while (left !== null) {
       /**
@@ -187,10 +173,10 @@ export const redoItem = (transaction, item, redoitems) => {
        */
       let leftTrace = left
       // trace redone until parent matches
-      while (leftTrace !== null && leftTrace.parent._item !== parentItem) {
+      while (leftTrace !== null && /** @type {AbstractType<any>} */ (leftTrace.parent)._item !== parentItem) {
         leftTrace = leftTrace.redone === null ? null : getItemCleanStart(transaction, leftTrace.redone)
       }
-      if (leftTrace !== null && leftTrace.parent._item === parentItem) {
+      if (leftTrace !== null && /** @type {AbstractType<any>} */ (leftTrace.parent)._item === parentItem) {
         left = leftTrace
         break
       }
@@ -202,27 +188,51 @@ export const redoItem = (transaction, item, redoitems) => {
        */
       let rightTrace = right
       // trace redone until parent matches
-      while (rightTrace !== null && rightTrace.parent._item !== parentItem) {
+      while (rightTrace !== null && /** @type {AbstractType<any>} */ (rightTrace.parent)._item !== parentItem) {
         rightTrace = rightTrace.redone === null ? null : getItemCleanStart(transaction, rightTrace.redone)
       }
-      if (rightTrace !== null && rightTrace.parent._item === parentItem) {
+      if (rightTrace !== null && /** @type {AbstractType<any>} */ (rightTrace.parent)._item === parentItem) {
         right = rightTrace
         break
       }
       right = right.right
     }
+  } else {
+    right = null
+    if (item.right && !ignoreRemoteMapChanges) {
+      left = item
+      // Iterate right while right is in itemsToDelete
+      // If it is intended to delete right while item is redone, we can expect that item should replace right.
+      while (left !== null && left.right !== null && isDeleted(itemsToDelete, left.right.id)) {
+        left = left.right
+      }
+      // follow redone
+      // trace redone until parent matches
+      while (left !== null && left.redone !== null) {
+        left = getItemCleanStart(transaction, left.redone)
+      }
+      if (left && left.right !== null) {
+        // It is not possible to redo this item because it conflicts with a
+        // change from another client
+        return null
+      }
+    } else {
+      left = parentType._map.get(item.parentSub) || null
+    }
   }
+  const nextClock = getState(store, ownClientID)
+  const nextId = createID(ownClientID, nextClock)
   const redoneItem = new Item(
-    nextID(transaction),
-    left, left === null ? null : left.lastId,
-    right, right === null ? null : right.id,
-    parentItem === null ? item.parent : /** @type {ContentType} */ (parentItem.content).type,
+    nextId,
+    left, left && left.lastId,
+    right, right && right.id,
+    parentType,
     item.parentSub,
     item.content.copy()
   )
-  item.redone = redoneItem.id
+  item.redone = nextId
   keepItem(redoneItem, true)
-  redoneItem.integrate(transaction)
+  redoneItem.integrate(transaction, 0)
   return redoneItem
 }
 
@@ -236,7 +246,7 @@ export class Item extends AbstractStruct {
    * @param {ID | null} origin
    * @param {Item | null} right
    * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
+   * @param {AbstractType<any>|ID|null} parent Is a type if integrated, is null if it is possible to copy parent from left or right, is ID before integration to search for it.
    * @param {string | null} parentSub
    * @param {AbstractContent} content
    */
@@ -245,7 +255,6 @@ export class Item extends AbstractStruct {
     /**
      * The item that was originally to the left of this item.
      * @type {ID | null}
-     * @readonly
      */
     this.origin = origin
     /**
@@ -260,14 +269,11 @@ export class Item extends AbstractStruct {
     this.right = right
     /**
      * The item that was originally to the right of this item.
-     * @readonly
      * @type {ID | null}
      */
     this.rightOrigin = rightOrigin
     /**
-     * The parent type.
-     * @type {AbstractType<any>}
-     * @readonly
+     * @type {AbstractType<any>|ID|null}
      */
     this.parent = parent
     /**
@@ -276,16 +282,10 @@ export class Item extends AbstractStruct {
      * to insert this item. If `parentSub = null` type._start is the list in
      * which to insert to. Otherwise it is `parent._map`.
      * @type {String | null}
-     * @readonly
      */
     this.parentSub = parentSub
     /**
-     * Whether this item was deleted or not.
-     * @type {Boolean}
-     */
-    this.deleted = false
-    /**
-     * If this type's effect is reundone this type refers to the type that undid
+     * If this type's effect is redone this type refers to the type that undid
      * this operation.
      * @type {ID | null}
      */
@@ -294,109 +294,235 @@ export class Item extends AbstractStruct {
      * @type {AbstractContent}
      */
     this.content = content
-    this.length = content.getLength()
-    this.countable = content.isCountable()
     /**
-     * If true, do not garbage collect this Item.
+     * bit1: keep
+     * bit2: countable
+     * bit3: deleted
+     * bit4: mark - mark node as fast-search-marker
+     * @type {number} byte
      */
-    this.keep = false
+    this.info = this.content.isCountable() ? binary.BIT2 : 0
+  }
+
+  /**
+   * This is used to mark the item as an indexed fast-search marker
+   *
+   * @type {boolean}
+   */
+  set marker (isMarked) {
+    if (((this.info & binary.BIT4) > 0) !== isMarked) {
+      this.info ^= binary.BIT4
+    }
+  }
+
+  get marker () {
+    return (this.info & binary.BIT4) > 0
+  }
+
+  /**
+   * If true, do not garbage collect this Item.
+   */
+  get keep () {
+    return (this.info & binary.BIT1) > 0
+  }
+
+  set keep (doKeep) {
+    if (this.keep !== doKeep) {
+      this.info ^= binary.BIT1
+    }
+  }
+
+  get countable () {
+    return (this.info & binary.BIT2) > 0
+  }
+
+  /**
+   * Whether this item was deleted or not.
+   * @type {Boolean}
+   */
+  get deleted () {
+    return (this.info & binary.BIT3) > 0
+  }
+
+  set deleted (doDelete) {
+    if (this.deleted !== doDelete) {
+      this.info ^= binary.BIT3
+    }
+  }
+
+  markDeleted () {
+    this.info |= binary.BIT3
+  }
+
+  /**
+   * Return the creator clientID of the missing op or define missing items and return null.
+   *
+   * @param {Transaction} transaction
+   * @param {StructStore} store
+   * @return {null | number}
+   */
+  getMissing (transaction, store) {
+    if (this.origin && this.origin.client !== this.id.client && this.origin.clock >= getState(store, this.origin.client)) {
+      return this.origin.client
+    }
+    if (this.rightOrigin && this.rightOrigin.client !== this.id.client && this.rightOrigin.clock >= getState(store, this.rightOrigin.client)) {
+      return this.rightOrigin.client
+    }
+    if (this.parent && this.parent.constructor === ID && this.id.client !== this.parent.client && this.parent.clock >= getState(store, this.parent.client)) {
+      return this.parent.client
+    }
+
+    // We have all missing ids, now find the items
+
+    if (this.origin) {
+      this.left = getItemCleanEnd(transaction, store, this.origin)
+      this.origin = this.left.lastId
+    }
+    if (this.rightOrigin) {
+      this.right = getItemCleanStart(transaction, this.rightOrigin)
+      this.rightOrigin = this.right.id
+    }
+    if ((this.left && this.left.constructor === GC) || (this.right && this.right.constructor === GC)) {
+      this.parent = null
+    }
+    // only set parent if this shouldn't be garbage collected
+    if (!this.parent) {
+      if (this.left && this.left.constructor === Item) {
+        this.parent = this.left.parent
+        this.parentSub = this.left.parentSub
+      }
+      if (this.right && this.right.constructor === Item) {
+        this.parent = this.right.parent
+        this.parentSub = this.right.parentSub
+      }
+    } else if (this.parent.constructor === ID) {
+      const parentItem = getItem(store, this.parent)
+      if (parentItem.constructor === GC) {
+        this.parent = null
+      } else {
+        this.parent = /** @type {ContentType} */ (parentItem.content).type
+      }
+    }
+    return null
   }
 
   /**
    * @param {Transaction} transaction
+   * @param {number} offset
    */
-  integrate (transaction) {
-    const store = transaction.doc.store
-    const id = this.id
-    const parent = this.parent
-    const parentSub = this.parentSub
-    const length = this.length
-    /**
-     * @type {Item|null}
-     */
-    let o
-    // set o to the first conflicting item
-    if (this.left !== null) {
-      o = this.left.right
-    } else if (parentSub !== null) {
-      o = parent._map.get(parentSub) || null
-      while (o !== null && o.left !== null) {
-        o = o.left
-      }
-    } else {
-      o = parent._start
+  integrate (transaction, offset) {
+    if (offset > 0) {
+      this.id.clock += offset
+      this.left = getItemCleanEnd(transaction, transaction.doc.store, createID(this.id.client, this.id.clock - 1))
+      this.origin = this.left.lastId
+      this.content = this.content.splice(offset)
+      this.length -= offset
     }
-    // TODO: use something like DeleteSet here (a tree implementation would be best)
-    /**
-     * @type {Set<Item>}
-     */
-    const conflictingItems = new Set()
-    /**
-     * @type {Set<Item>}
-     */
-    const itemsBeforeOrigin = new Set()
-    // Let c in conflictingItems, b in itemsBeforeOrigin
-    // ***{origin}bbbb{this}{c,b}{c,b}{o}***
-    // Note that conflictingItems is a subset of itemsBeforeOrigin
-    while (o !== null && o !== this.right) {
-      itemsBeforeOrigin.add(o)
-      conflictingItems.add(o)
-      if (compareIDs(this.origin, o.origin)) {
-        // case 1
-        if (o.id.client < id.client) {
-          this.left = o
-          conflictingItems.clear()
+
+    if (this.parent) {
+      if ((!this.left && (!this.right || this.right.left !== null)) || (this.left && this.left.right !== this.right)) {
+        /**
+         * @type {Item|null}
+         */
+        let left = this.left
+
+        /**
+         * @type {Item|null}
+         */
+        let o
+        // set o to the first conflicting item
+        if (left !== null) {
+          o = left.right
+        } else if (this.parentSub !== null) {
+          o = /** @type {AbstractType<any>} */ (this.parent)._map.get(this.parentSub) || null
+          while (o !== null && o.left !== null) {
+            o = o.left
+          }
+        } else {
+          o = /** @type {AbstractType<any>} */ (this.parent)._start
         }
-      } else if (o.origin !== null && itemsBeforeOrigin.has(getItem(store, o.origin))) {
-        // case 2
-        if (o.origin === null || !conflictingItems.has(getItem(store, o.origin))) {
-          this.left = o
-          conflictingItems.clear()
+        // TODO: use something like DeleteSet here (a tree implementation would be best)
+        // @todo use global set definitions
+        /**
+         * @type {Set<Item>}
+         */
+        const conflictingItems = new Set()
+        /**
+         * @type {Set<Item>}
+         */
+        const itemsBeforeOrigin = new Set()
+        // Let c in conflictingItems, b in itemsBeforeOrigin
+        // ***{origin}bbbb{this}{c,b}{c,b}{o}***
+        // Note that conflictingItems is a subset of itemsBeforeOrigin
+        while (o !== null && o !== this.right) {
+          itemsBeforeOrigin.add(o)
+          conflictingItems.add(o)
+          if (compareIDs(this.origin, o.origin)) {
+            // case 1
+            if (o.id.client < this.id.client) {
+              left = o
+              conflictingItems.clear()
+            } else if (compareIDs(this.rightOrigin, o.rightOrigin)) {
+              // this and o are conflicting and point to the same integration points. The id decides which item comes first.
+              // Since this is to the left of o, we can break here
+              break
+            } // else, o might be integrated before an item that this conflicts with. If so, we will find it in the next iterations
+          } else if (o.origin !== null && itemsBeforeOrigin.has(getItem(transaction.doc.store, o.origin))) { // use getItem instead of getItemCleanEnd because we don't want / need to split items.
+            // case 2
+            if (!conflictingItems.has(getItem(transaction.doc.store, o.origin))) {
+              left = o
+              conflictingItems.clear()
+            }
+          } else {
+            break
+          }
+          o = o.right
         }
-      } else {
-        break
+        this.left = left
       }
-      o = o.right
-    }
-    // reconnect left/right + update parent map/start if necessary
-    if (this.left !== null) {
-      const right = this.left.right
-      this.right = right
-      this.left.right = this
-    } else {
-      let r
-      if (parentSub !== null) {
-        r = parent._map.get(parentSub) || null
-        while (r !== null && r.left !== null) {
-          r = r.left
-        }
-      } else {
-        r = parent._start
-        parent._start = this
-      }
-      this.right = r
-    }
-    if (this.right !== null) {
-      this.right.left = this
-    } else if (parentSub !== null) {
-      // set as current parent value if right === null and this is parentSub
-      parent._map.set(parentSub, this)
+      // reconnect left/right + update parent map/start if necessary
       if (this.left !== null) {
-        // this is the current attribute value of parent. delete right
-        this.left.delete(transaction)
+        const right = this.left.right
+        this.right = right
+        this.left.right = this
+      } else {
+        let r
+        if (this.parentSub !== null) {
+          r = /** @type {AbstractType<any>} */ (this.parent)._map.get(this.parentSub) || null
+          while (r !== null && r.left !== null) {
+            r = r.left
+          }
+        } else {
+          r = /** @type {AbstractType<any>} */ (this.parent)._start
+          ;/** @type {AbstractType<any>} */ (this.parent)._start = this
+        }
+        this.right = r
       }
-    }
-    // adjust length of parent
-    if (parentSub === null && this.countable && !this.deleted) {
-      parent._length += length
-    }
-    addStruct(store, this)
-    this.content.integrate(transaction, this)
-    // add parent to transaction.changed
-    addChangedTypeToTransaction(transaction, parent, parentSub)
-    if ((parent._item !== null && parent._item.deleted) || (this.right !== null && parentSub !== null)) {
-      // delete if parent is deleted or if this is not the current attribute value of parent
-      this.delete(transaction)
+      if (this.right !== null) {
+        this.right.left = this
+      } else if (this.parentSub !== null) {
+        // set as current parent value if right === null and this is parentSub
+        /** @type {AbstractType<any>} */ (this.parent)._map.set(this.parentSub, this)
+        if (this.left !== null) {
+          // this is the current attribute value of parent. delete right
+          this.left.delete(transaction)
+        }
+      }
+      // adjust length of parent
+      if (this.parentSub === null && this.countable && !this.deleted) {
+        /** @type {AbstractType<any>} */ (this.parent)._length += this.length
+      }
+      addStruct(transaction.doc.store, this)
+      this.content.integrate(transaction, this)
+      // add parent to transaction.changed
+      addChangedTypeToTransaction(transaction, /** @type {AbstractType<any>} */ (this.parent), this.parentSub)
+      if ((/** @type {AbstractType<any>} */ (this.parent)._item !== null && /** @type {AbstractType<any>} */ (this.parent)._item.deleted) || (this.parentSub !== null && this.right !== null)) {
+        // delete if parent is deleted or if this is not the current attribute value of parent
+        this.delete(transaction)
+      }
+    } else {
+      // parent is not defined. Integrate GC struct instead
+      new GC(this.id, this.length).integrate(transaction, 0)
     }
   }
 
@@ -426,7 +552,8 @@ export class Item extends AbstractStruct {
    * Computes the last content address of this Item.
    */
   get lastId () {
-    return createID(this.id.client, this.id.clock + this.length - 1)
+    // allocating ids is pretty costly because of the amount of ids created, so we try to reuse whenever possible
+    return this.length === 1 ? this.id : createID(this.id.client, this.id.clock + this.length - 1)
   }
 
   /**
@@ -437,6 +564,7 @@ export class Item extends AbstractStruct {
    */
   mergeWith (right) {
     if (
+      this.constructor === right.constructor &&
       compareIDs(right.origin, this.lastId) &&
       this.right === right &&
       compareIDs(this.rightOrigin, right.rightOrigin) &&
@@ -448,6 +576,19 @@ export class Item extends AbstractStruct {
       this.content.constructor === right.content.constructor &&
       this.content.mergeWith(right.content)
     ) {
+      const searchMarker = /** @type {AbstractType<any>} */ (this.parent)._searchMarker
+      if (searchMarker) {
+        searchMarker.forEach(marker => {
+          if (marker.p === right) {
+            // right is going to be "forgotten" so we need to update the marker
+            marker.p = this
+            // adjust marker index
+            if (!this.deleted && this.countable) {
+              marker.index -= this.length
+            }
+          }
+        })
+      }
       if (right.keep) {
         this.keep = true
       }
@@ -468,14 +609,14 @@ export class Item extends AbstractStruct {
    */
   delete (transaction) {
     if (!this.deleted) {
-      const parent = this.parent
+      const parent = /** @type {AbstractType<any>} */ (this.parent)
       // adjust the length of parent
       if (this.countable && this.parentSub === null) {
         parent._length -= this.length
       }
-      this.deleted = true
-      addToDeleteSet(transaction.deleteSet, this.id, this.length)
-      maplib.setIfUndefined(transaction.changed, parent, set.create).add(this.parentSub)
+      this.markDeleted()
+      addToDeleteSet(transaction.deleteSet, this.id.client, this.id.clock, this.length)
+      addChangedTypeToTransaction(transaction, parent, this.parentSub)
       this.content.delete(transaction)
     }
   }
@@ -502,7 +643,7 @@ export class Item extends AbstractStruct {
    *
    * This is called when this Item is sent to a remote peer.
    *
-   * @param {encoding.Encoder} encoder The encoder to write data to.
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
    * @param {number} offset
    */
   write (encoder, offset) {
@@ -513,27 +654,38 @@ export class Item extends AbstractStruct {
       (origin === null ? 0 : binary.BIT8) | // origin is defined
       (rightOrigin === null ? 0 : binary.BIT7) | // right origin is defined
       (parentSub === null ? 0 : binary.BIT6) // parentSub is non-null
-    encoding.writeUint8(encoder, info)
+    encoder.writeInfo(info)
     if (origin !== null) {
-      writeID(encoder, origin)
+      encoder.writeLeftID(origin)
     }
     if (rightOrigin !== null) {
-      writeID(encoder, rightOrigin)
+      encoder.writeRightID(rightOrigin)
     }
     if (origin === null && rightOrigin === null) {
-      const parent = this.parent
-      if (parent._item === null) {
-        // parent type on y._map
-        // find the correct key
-        const ykey = findRootTypeKey(parent)
-        encoding.writeVarUint(encoder, 1) // write parentYKey
-        encoding.writeVarString(encoder, ykey)
+      const parent = /** @type {AbstractType<any>} */ (this.parent)
+      if (parent._item !== undefined) {
+        const parentItem = parent._item
+        if (parentItem === null) {
+          // parent type on y._map
+          // find the correct key
+          const ykey = findRootTypeKey(parent)
+          encoder.writeParentInfo(true) // write parentYKey
+          encoder.writeString(ykey)
+        } else {
+          encoder.writeParentInfo(false) // write parent id
+          encoder.writeLeftID(parentItem.id)
+        }
+      } else if (parent.constructor === String) { // this edge case was added by differential updates
+        encoder.writeParentInfo(true) // write parentYKey
+        encoder.writeString(parent)
+      } else if (parent.constructor === ID) {
+        encoder.writeParentInfo(false) // write parent id
+        encoder.writeLeftID(parent)
       } else {
-        encoding.writeVarUint(encoder, 0) // write parent id
-        writeID(encoder, parent._item.id)
+        error.unexpectedCase()
       }
       if (parentSub !== null) {
-        encoding.writeVarString(encoder, parentSub)
+        encoder.writeString(parentSub)
       }
     }
     this.content.write(encoder, offset)
@@ -541,26 +693,28 @@ export class Item extends AbstractStruct {
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @param {number} info
  */
-const readItemContent = (decoder, info) => contentRefs[info & binary.BITS5](decoder)
+export const readItemContent = (decoder, info) => contentRefs[info & binary.BITS5](decoder)
 
 /**
  * A lookup map for reading Item content.
  *
- * @type {Array<function(decoding.Decoder):AbstractContent>}
+ * @type {Array<function(UpdateDecoderV1 | UpdateDecoderV2):AbstractContent>}
  */
 export const contentRefs = [
-  () => { throw error.unexpectedCase() }, // GC is not ItemContent
-  readContentDeleted,
-  readContentJSON,
-  readContentBinary,
-  readContentString,
-  readContentEmbed,
-  readContentFormat,
-  readContentType,
-  readContentAny
+  () => { error.unexpectedCase() }, // GC is not ItemContent
+  readContentDeleted, // 1
+  readContentJSON, // 2
+  readContentBinary, // 3
+  readContentString, // 4
+  readContentEmbed, // 5
+  readContentFormat, // 6
+  readContentType, // 7
+  readContentAny, // 8
+  readContentDoc, // 9
+  () => { error.unexpectedCase() } // 10 - Skip is not ItemContent
 ]
 
 /**
@@ -640,7 +794,7 @@ export class AbstractContent {
   }
 
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    * @param {number} offset
    */
   write (encoder, offset) {
@@ -654,125 +808,3 @@ export class AbstractContent {
     throw error.methodUnimplemented()
   }
 }
-
-/**
- * @private
- */
-export class ItemRef extends AbstractStructRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(id)
-    /**
-     * The item that was originally to the left of this item.
-     * @type {ID | null}
-     */
-    this.left = (info & binary.BIT8) === binary.BIT8 ? readID(decoder) : null
-    /**
-     * The item that was originally to the right of this item.
-     * @type {ID | null}
-     */
-    this.right = (info & binary.BIT7) === binary.BIT7 ? readID(decoder) : null
-    const canCopyParentInfo = (info & (binary.BIT7 | binary.BIT8)) === 0
-    const hasParentYKey = canCopyParentInfo ? decoding.readVarUint(decoder) === 1 : false
-    /**
-     * If parent = null and neither left nor right are defined, then we know that `parent` is child of `y`
-     * and we read the next string as parentYKey.
-     * It indicates how we store/retrieve parent from `y.share`
-     * @type {string|null}
-     */
-    this.parentYKey = canCopyParentInfo && hasParentYKey ? decoding.readVarString(decoder) : null
-    /**
-     * The parent type.
-     * @type {ID | null}
-     */
-    this.parent = canCopyParentInfo && !hasParentYKey ? readID(decoder) : null
-    /**
-     * If the parent refers to this item with some kind of key (e.g. YMap, the
-     * key is specified here. The key is then used to refer to the list in which
-     * to insert this item. If `parentSub = null` type._start is the list in
-     * which to insert to. Otherwise it is `parent._map`.
-     * @type {String | null}
-     */
-    this.parentSub = canCopyParentInfo && (info & binary.BIT6) === binary.BIT6 ? decoding.readVarString(decoder) : null
-    const missing = this._missing
-    if (this.left !== null) {
-      missing.push(this.left)
-    }
-    if (this.right !== null) {
-      missing.push(this.right)
-    }
-    if (this.parent !== null) {
-      missing.push(this.parent)
-    }
-    /**
-     * @type {AbstractContent}
-     */
-    this.content = readItemContent(decoder, info)
-    this.length = this.content.getLength()
-  }
-
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {Item|GC}
-   */
-  toStruct (transaction, store, offset) {
-    if (offset > 0) {
-      /**
-       * @type {ID}
-       */
-      const id = this.id
-      this.id = createID(id.client, id.clock + offset)
-      this.left = createID(this.id.client, this.id.clock - 1)
-      this.content = this.content.splice(offset)
-      this.length -= offset
-    }
-
-    const left = this.left === null ? null : getItemCleanEnd(transaction, store, this.left)
-    const right = this.right === null ? null : getItemCleanStart(transaction, this.right)
-    let parent = null
-    let parentSub = this.parentSub
-    if (this.parent !== null) {
-      const parentItem = getItem(store, this.parent)
-      // Edge case: toStruct is called with an offset > 0. In this case left is defined.
-      // Depending in which order structs arrive, left may be GC'd and the parent not
-      // deleted. This is why we check if left is GC'd. Strictly we don't have
-      // to check if right is GC'd, but we will in case we run into future issues
-      if (!parentItem.deleted && (left === null || left.constructor !== GC) && (right === null || right.constructor !== GC)) {
-        parent = /** @type {ContentType} */ (parentItem.content).type
-      }
-    } else if (this.parentYKey !== null) {
-      parent = transaction.doc.get(this.parentYKey)
-    } else if (left !== null) {
-      if (left.constructor !== GC) {
-        parent = left.parent
-        parentSub = left.parentSub
-      }
-    } else if (right !== null) {
-      if (right.constructor !== GC) {
-        parent = right.parent
-        parentSub = right.parentSub
-      }
-    } else {
-      throw error.unexpectedCase()
-    }
-
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new Item(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.content
-      )
-  }
-}

src/structs/Skip.js

@@ -0,0 +1,60 @@
+
+import {
+  AbstractStruct,
+  UpdateEncoderV1, UpdateEncoderV2, StructStore, Transaction, ID // eslint-disable-line
+} from '../internals.js'
+import * as error from 'lib0/error'
+import * as encoding from 'lib0/encoding'
+
+export const structSkipRefNumber = 10
+
+/**
+ * @private
+ */
+export class Skip extends AbstractStruct {
+  get deleted () {
+    return true
+  }
+
+  delete () {}
+
+  /**
+   * @param {Skip} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    if (this.constructor !== right.constructor) {
+      return false
+    }
+    this.length += right.length
+    return true
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {number} offset
+   */
+  integrate (transaction, offset) {
+    // skip structs cannot be integrated
+    error.unexpectedCase()
+  }
+
+  /**
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoder.writeInfo(structSkipRefNumber)
+    // write as VarUint because Skips can't make use of predictable length-encoding
+    encoding.writeVarUint(encoder.restEncoder, this.length - offset)
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {StructStore} store
+   * @return {null | number}
+   */
+  getMissing (transaction, store) {
+    return null
+  }
+}

src/types/AbstractType.js

@@ -4,20 +4,210 @@ import {
   callEventHandlerListeners,
   addEventHandlerListener,
   createEventHandler,
-  nextID,
+  getState,
   isVisible,
   ContentType,
+  createID,
   ContentAny,
   ContentBinary,
-  createID,
   getItemCleanStart,
-  Doc, Snapshot, Transaction, EventHandler, YEvent, Item, // eslint-disable-line
+  ContentDoc, YText, YArray, UpdateEncoderV1, UpdateEncoderV2, Doc, Snapshot, Transaction, EventHandler, YEvent, Item, // eslint-disable-line
 } from '../internals.js'
 
-import * as map from 'lib0/map.js'
-import * as iterator from 'lib0/iterator.js'
-import * as error from 'lib0/error.js'
-import * as encoding from 'lib0/encoding.js' // eslint-disable-line
+import * as map from 'lib0/map'
+import * as iterator from 'lib0/iterator'
+import * as error from 'lib0/error'
+import * as math from 'lib0/math'
+
+const maxSearchMarker = 80
+
+/**
+ * A unique timestamp that identifies each marker.
+ *
+ * Time is relative,.. this is more like an ever-increasing clock.
+ *
+ * @type {number}
+ */
+let globalSearchMarkerTimestamp = 0
+
+export class ArraySearchMarker {
+  /**
+   * @param {Item} p
+   * @param {number} index
+   */
+  constructor (p, index) {
+    p.marker = true
+    this.p = p
+    this.index = index
+    this.timestamp = globalSearchMarkerTimestamp++
+  }
+}
+
+/**
+ * @param {ArraySearchMarker} marker
+ */
+const refreshMarkerTimestamp = marker => { marker.timestamp = globalSearchMarkerTimestamp++ }
+
+/**
+ * This is rather complex so this function is the only thing that should overwrite a marker
+ *
+ * @param {ArraySearchMarker} marker
+ * @param {Item} p
+ * @param {number} index
+ */
+const overwriteMarker = (marker, p, index) => {
+  marker.p.marker = false
+  marker.p = p
+  p.marker = true
+  marker.index = index
+  marker.timestamp = globalSearchMarkerTimestamp++
+}
+
+/**
+ * @param {Array<ArraySearchMarker>} searchMarker
+ * @param {Item} p
+ * @param {number} index
+ */
+const markPosition = (searchMarker, p, index) => {
+  if (searchMarker.length >= maxSearchMarker) {
+    // override oldest marker (we don't want to create more objects)
+    const marker = searchMarker.reduce((a, b) => a.timestamp < b.timestamp ? a : b)
+    overwriteMarker(marker, p, index)
+    return marker
+  } else {
+    // create new marker
+    const pm = new ArraySearchMarker(p, index)
+    searchMarker.push(pm)
+    return pm
+  }
+}
+
+/**
+ * Search marker help us to find positions in the associative array faster.
+ *
+ * They speed up the process of finding a position without much bookkeeping.
+ *
+ * A maximum of `maxSearchMarker` objects are created.
+ *
+ * This function always returns a refreshed marker (updated timestamp)
+ *
+ * @param {AbstractType<any>} yarray
+ * @param {number} index
+ */
+export const findMarker = (yarray, index) => {
+  if (yarray._start === null || index === 0 || yarray._searchMarker === null) {
+    return null
+  }
+  const marker = yarray._searchMarker.length === 0 ? null : yarray._searchMarker.reduce((a, b) => math.abs(index - a.index) < math.abs(index - b.index) ? a : b)
+  let p = yarray._start
+  let pindex = 0
+  if (marker !== null) {
+    p = marker.p
+    pindex = marker.index
+    refreshMarkerTimestamp(marker) // we used it, we might need to use it again
+  }
+  // iterate to right if possible
+  while (p.right !== null && pindex < index) {
+    if (!p.deleted && p.countable) {
+      if (index < pindex + p.length) {
+        break
+      }
+      pindex += p.length
+    }
+    p = p.right
+  }
+  // iterate to left if necessary (might be that pindex > index)
+  while (p.left !== null && pindex > index) {
+    p = p.left
+    if (!p.deleted && p.countable) {
+      pindex -= p.length
+    }
+  }
+  // we want to make sure that p can't be merged with left, because that would screw up everything
+  // in that cas just return what we have (it is most likely the best marker anyway)
+  // iterate to left until p can't be merged with left
+  while (p.left !== null && p.left.id.client === p.id.client && p.left.id.clock + p.left.length === p.id.clock) {
+    p = p.left
+    if (!p.deleted && p.countable) {
+      pindex -= p.length
+    }
+  }
+
+  // @todo remove!
+  // assure position
+  // {
+  //   let start = yarray._start
+  //   let pos = 0
+  //   while (start !== p) {
+  //     if (!start.deleted && start.countable) {
+  //       pos += start.length
+  //     }
+  //     start = /** @type {Item} */ (start.right)
+  //   }
+  //   if (pos !== pindex) {
+  //     debugger
+  //     throw new Error('Gotcha position fail!')
+  //   }
+  // }
+  // if (marker) {
+  //   if (window.lengthes == null) {
+  //     window.lengthes = []
+  //     window.getLengthes = () => window.lengthes.sort((a, b) => a - b)
+  //   }
+  //   window.lengthes.push(marker.index - pindex)
+  //   console.log('distance', marker.index - pindex, 'len', p && p.parent.length)
+  // }
+  if (marker !== null && math.abs(marker.index - pindex) < /** @type {YText|YArray<any>} */ (p.parent).length / maxSearchMarker) {
+    // adjust existing marker
+    overwriteMarker(marker, p, pindex)
+    return marker
+  } else {
+    // create new marker
+    return markPosition(yarray._searchMarker, p, pindex)
+  }
+}
+
+/**
+ * Update markers when a change happened.
+ *
+ * This should be called before doing a deletion!
+ *
+ * @param {Array<ArraySearchMarker>} searchMarker
+ * @param {number} index
+ * @param {number} len If insertion, len is positive. If deletion, len is negative.
+ */
+export const updateMarkerChanges = (searchMarker, index, len) => {
+  for (let i = searchMarker.length - 1; i >= 0; i--) {
+    const m = searchMarker[i]
+    if (len > 0) {
+      /**
+       * @type {Item|null}
+       */
+      let p = m.p
+      p.marker = false
+      // Ideally we just want to do a simple position comparison, but this will only work if
+      // search markers don't point to deleted items for formats.
+      // Iterate marker to prev undeleted countable position so we know what to do when updating a position
+      while (p && (p.deleted || !p.countable)) {
+        p = p.left
+        if (p && !p.deleted && p.countable) {
+          // adjust position. the loop should break now
+          m.index -= p.length
+        }
+      }
+      if (p === null || p.marker === true) {
+        // remove search marker if updated position is null or if position is already marked
+        searchMarker.splice(i, 1)
+        continue
+      }
+      m.p = p
+      p.marker = true
+    }
+    if (index < m.index || (len > 0 && index === m.index)) { // a simple index <= m.index check would actually suffice
+      m.index = math.max(index, m.index + len)
+    }
+  }
+}
 
 /**
  * Accumulate all (list) children of a type and return them as an Array.
@@ -53,7 +243,7 @@ export const callTypeObservers = (type, transaction, event) => {
     if (type._item === null) {
       break
     }
-    type = type._item.parent
+    type = /** @type {AbstractType<any>} */ (type._item.parent)
   }
   callEventHandlerListeners(changedType._eH, event, transaction)
 }
@@ -88,9 +278,20 @@ export class AbstractType {
     this._eH = createEventHandler()
     /**
      * Deep event handlers
-     * @type {EventHandler<Array<YEvent>,Transaction>}
+     * @type {EventHandler<Array<YEvent<any>>,Transaction>}
      */
     this._dEH = createEventHandler()
+    /**
+     * @type {null | Array<ArraySearchMarker>}
+     */
+    this._searchMarker = null
+  }
+
+  /**
+   * @return {AbstractType<any>|null}
+   */
+  get parent () {
+    return this._item ? /** @type {AbstractType<any>} */ (this._item.parent) : null
   }
 
   /**
@@ -116,9 +317,16 @@ export class AbstractType {
   }
 
   /**
-   * @param {encoding.Encoder} encoder
+   * @return {AbstractType<EventType>}
    */
-  _write (encoder) { }
+  clone () {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} _encoder
+   */
+  _write (_encoder) { }
 
   /**
    * The first non-deleted item
@@ -136,9 +344,13 @@ export class AbstractType {
    * Must be implemented by each type.
    *
    * @param {Transaction} transaction
-   * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
+   * @param {Set<null|string>} _parentSubs Keys changed on this type. `null` if list was modified.
    */
-  _callObserver (transaction, parentSubs) { /* skip if no type is specified */ }
+  _callObserver (transaction, _parentSubs) {
+    if (!transaction.local && this._searchMarker) {
+      this._searchMarker.length = 0
+    }
+  }
 
   /**
    * Observe all events that are created on this type.
@@ -152,7 +364,7 @@ export class AbstractType {
   /**
    * Observe all events that are created by this type and its children.
    *
-   * @param {function(Array<YEvent>,Transaction):void} f Observer function
+   * @param {function(Array<YEvent<any>>,Transaction):void} f Observer function
    */
   observeDeep (f) {
     addEventHandlerListener(this._dEH, f)
@@ -170,7 +382,7 @@ export class AbstractType {
   /**
    * Unregister an observer function.
    *
-   * @param {function(Array<YEvent>,Transaction):void} f Observer function
+   * @param {function(Array<YEvent<any>>,Transaction):void} f Observer function
    */
   unobserveDeep (f) {
     removeEventHandlerListener(this._dEH, f)
@@ -183,6 +395,43 @@ export class AbstractType {
   toJSON () {}
 }
 
+/**
+ * @param {AbstractType<any>} type
+ * @param {number} start
+ * @param {number} end
+ * @return {Array<any>}
+ *
+ * @private
+ * @function
+ */
+export const typeListSlice = (type, start, end) => {
+  if (start < 0) {
+    start = type._length + start
+  }
+  if (end < 0) {
+    end = type._length + end
+  }
+  let len = end - start
+  const cs = []
+  let n = type._start
+  while (n !== null && len > 0) {
+    if (n.countable && !n.deleted) {
+      const c = n.content.getContent()
+      if (c.length <= start) {
+        start -= c.length
+      } else {
+        for (let i = start; i < c.length && len > 0; i++) {
+          cs.push(c[i])
+          len--
+        }
+        start = 0
+      }
+    }
+    n = n.right
+  }
+  return cs
+}
+
 /**
  * @param {AbstractType<any>} type
  * @return {Array<any>}
@@ -354,7 +603,13 @@ export const typeListForEachSnapshot = (type, f, snapshot) => {
  * @function
  */
 export const typeListGet = (type, index) => {
-  for (let n = type._start; n !== null; n = n.right) {
+  const marker = findMarker(type, index)
+  let n = type._start
+  if (marker !== null) {
+    n = marker.p
+    index -= marker.index
+  }
+  for (; n !== null; n = n.right) {
     if (!n.deleted && n.countable) {
       if (index < n.length) {
         return n.content.getContent()[index]
@@ -368,69 +623,100 @@ export const typeListGet = (type, index) => {
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
  * @param {Item?} referenceItem
- * @param {Array<Object<string,any>|Array<any>|boolean|number|string|Uint8Array>} content
+ * @param {Array<Object<string,any>|Array<any>|boolean|number|null|string|Uint8Array>} content
  *
  * @private
  * @function
  */
 export const typeListInsertGenericsAfter = (transaction, parent, referenceItem, content) => {
   let left = referenceItem
+  const doc = transaction.doc
+  const ownClientId = doc.clientID
+  const store = doc.store
   const right = referenceItem === null ? parent._start : referenceItem.right
   /**
-   * @type {Array<Object|Array<any>|number>}
+   * @type {Array<Object|Array<any>|number|null>}
    */
   let jsonContent = []
   const packJsonContent = () => {
     if (jsonContent.length > 0) {
-      left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentAny(jsonContent))
-      left.integrate(transaction)
+      left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentAny(jsonContent))
+      left.integrate(transaction, 0)
       jsonContent = []
     }
   }
   content.forEach(c => {
-    switch (c.constructor) {
-      case Number:
-      case Object:
-      case Boolean:
-      case Array:
-      case String:
-        jsonContent.push(c)
-        break
-      default:
-        packJsonContent()
-        switch (c.constructor) {
-          case Uint8Array:
-          case ArrayBuffer:
-            left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentBinary(new Uint8Array(/** @type {Uint8Array} */ (c))))
-            left.integrate(transaction)
-            break
-          default:
-            if (c instanceof AbstractType) {
-              left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentType(c))
-              left.integrate(transaction)
-            } else {
-              throw new Error('Unexpected content type in insert operation')
-            }
-        }
+    if (c === null) {
+      jsonContent.push(c)
+    } else {
+      switch (c.constructor) {
+        case Number:
+        case Object:
+        case Boolean:
+        case Array:
+        case String:
+          jsonContent.push(c)
+          break
+        default:
+          packJsonContent()
+          switch (c.constructor) {
+            case Uint8Array:
+            case ArrayBuffer:
+              left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentBinary(new Uint8Array(/** @type {Uint8Array} */ (c))))
+              left.integrate(transaction, 0)
+              break
+            case Doc:
+              left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentDoc(/** @type {Doc} */ (c)))
+              left.integrate(transaction, 0)
+              break
+            default:
+              if (c instanceof AbstractType) {
+                left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentType(c))
+                left.integrate(transaction, 0)
+              } else {
+                throw new Error('Unexpected content type in insert operation')
+              }
+          }
+      }
     }
   })
   packJsonContent()
 }
 
+const lengthExceeded = error.create('Length exceeded!')
+
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
  * @param {number} index
- * @param {Array<Object<string,any>|Array<any>|number|string|Uint8Array>} content
+ * @param {Array<Object<string,any>|Array<any>|number|null|string|Uint8Array>} content
  *
  * @private
  * @function
  */
 export const typeListInsertGenerics = (transaction, parent, index, content) => {
+  if (index > parent._length) {
+    throw lengthExceeded
+  }
   if (index === 0) {
+    if (parent._searchMarker) {
+      updateMarkerChanges(parent._searchMarker, index, content.length)
+    }
     return typeListInsertGenericsAfter(transaction, parent, null, content)
   }
+  const startIndex = index
+  const marker = findMarker(parent, index)
   let n = parent._start
+  if (marker !== null) {
+    n = marker.p
+    index -= marker.index
+    // we need to iterate one to the left so that the algorithm works
+    if (index === 0) {
+      // @todo refactor this as it actually doesn't consider formats
+      n = n.prev // important! get the left undeleted item so that we can actually decrease index
+      index += (n && n.countable && !n.deleted) ? n.length : 0
+    }
+  }
   for (; n !== null; n = n.right) {
     if (!n.deleted && n.countable) {
       if (index <= n.length) {
@@ -443,6 +729,32 @@ export const typeListInsertGenerics = (transaction, parent, index, content) => {
       index -= n.length
     }
   }
+  if (parent._searchMarker) {
+    updateMarkerChanges(parent._searchMarker, startIndex, content.length)
+  }
+  return typeListInsertGenericsAfter(transaction, parent, n, content)
+}
+
+/**
+ * Pushing content is special as we generally want to push after the last item. So we don't have to update
+ * the serach marker.
+ *
+ * @param {Transaction} transaction
+ * @param {AbstractType<any>} parent
+ * @param {Array<Object<string,any>|Array<any>|number|null|string|Uint8Array>} content
+ *
+ * @private
+ * @function
+ */
+export const typeListPushGenerics = (transaction, parent, content) => {
+  // Use the marker with the highest index and iterate to the right.
+  const marker = (parent._searchMarker || []).reduce((maxMarker, currMarker) => currMarker.index > maxMarker.index ? currMarker : maxMarker, { index: 0, p: parent._start })
+  let n = marker.p
+  if (n) {
+    while (n.right) {
+      n = n.right
+    }
+  }
   return typeListInsertGenericsAfter(transaction, parent, n, content)
 }
 
@@ -457,7 +769,14 @@ export const typeListInsertGenerics = (transaction, parent, index, content) => {
  */
 export const typeListDelete = (transaction, parent, index, length) => {
   if (length === 0) { return }
+  const startIndex = index
+  const startLength = length
+  const marker = findMarker(parent, index)
   let n = parent._start
+  if (marker !== null) {
+    n = marker.p
+    index -= marker.index
+  }
   // compute the first item to be deleted
   for (; n !== null && index > 0; n = n.right) {
     if (!n.deleted && n.countable) {
@@ -479,7 +798,10 @@ export const typeListDelete = (transaction, parent, index, length) => {
     n = n.right
   }
   if (length > 0) {
-    throw error.create('array length exceeded')
+    throw lengthExceeded
+  }
+  if (parent._searchMarker) {
+    updateMarkerChanges(parent._searchMarker, startIndex, -startLength + length /* in case we remove the above exception */)
   }
 }
 
@@ -502,13 +824,15 @@ export const typeMapDelete = (transaction, parent, key) => {
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
  * @param {string} key
- * @param {Object|number|Array<any>|string|Uint8Array|AbstractType<any>} value
+ * @param {Object|number|null|Array<any>|string|Uint8Array|AbstractType<any>} value
  *
  * @private
  * @function
  */
 export const typeMapSet = (transaction, parent, key, value) => {
   const left = parent._map.get(key) || null
+  const doc = transaction.doc
+  const ownClientId = doc.clientID
   let content
   if (value == null) {
     content = new ContentAny([value])
@@ -524,6 +848,9 @@ export const typeMapSet = (transaction, parent, key, value) => {
       case Uint8Array:
         content = new ContentBinary(/** @type {Uint8Array} */ (value))
         break
+      case Doc:
+        content = new ContentDoc(/** @type {Doc} */ (value))
+        break
       default:
         if (value instanceof AbstractType) {
           content = new ContentType(value)
@@ -532,13 +859,13 @@ export const typeMapSet = (transaction, parent, key, value) => {
         }
     }
   }
-  new Item(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, content).integrate(transaction)
+  new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, null, null, parent, key, content).integrate(transaction, 0)
 }
 
 /**
  * @param {AbstractType<any>} parent
  * @param {string} key
- * @return {Object<string,any>|number|Array<any>|string|Uint8Array|AbstractType<any>|undefined}
+ * @return {Object<string,any>|number|null|Array<any>|string|Uint8Array|AbstractType<any>|undefined}
  *
  * @private
  * @function
@@ -550,7 +877,7 @@ export const typeMapGet = (parent, key) => {
 
 /**
  * @param {AbstractType<any>} parent
- * @return {Object<string,Object<string,any>|number|Array<any>|string|Uint8Array|AbstractType<any>|undefined>}
+ * @return {Object<string,Object<string,any>|number|null|Array<any>|string|Uint8Array|AbstractType<any>|undefined>}
  *
  * @private
  * @function
@@ -560,11 +887,11 @@ export const typeMapGetAll = (parent) => {
    * @type {Object<string,any>}
    */
   const res = {}
-  for (const [key, value] of parent._map) {
+  parent._map.forEach((value, key) => {
     if (!value.deleted) {
       res[key] = value.content.getContent()[value.length - 1]
     }
-  }
+  })
   return res
 }
 
@@ -585,7 +912,7 @@ export const typeMapHas = (parent, key) => {
  * @param {AbstractType<any>} parent
  * @param {string} key
  * @param {Snapshot} snapshot
- * @return {Object<string,any>|number|Array<any>|string|Uint8Array|AbstractType<any>|undefined}
+ * @return {Object<string,any>|number|null|Array<any>|string|Uint8Array|AbstractType<any>|undefined}
  *
  * @private
  * @function

src/types/YArray.js

@@ -10,20 +10,20 @@ import {
   typeListForEach,
   typeListCreateIterator,
   typeListInsertGenerics,
+  typeListPushGenerics,
   typeListDelete,
   typeListMap,
   YArrayRefID,
   callTypeObservers,
   transact,
-  Doc, Transaction, Item // eslint-disable-line
+  ArraySearchMarker, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, Doc, Transaction, Item // eslint-disable-line
 } from '../internals.js'
-
-import * as decoding from 'lib0/decoding.js' // eslint-disable-line
-import * as encoding from 'lib0/encoding.js'
+import { typeListSlice } from './AbstractType.js'
 
 /**
  * Event that describes the changes on a YArray
  * @template T
+ * @extends YEvent<YArray<T>>
  */
 export class YArrayEvent extends YEvent {
   /**
@@ -40,7 +40,7 @@ export class YArrayEvent extends YEvent {
  * A shared Array implementation.
  * @template T
  * @extends AbstractType<YArrayEvent<T>>
- * @implements {IterableIterator<T>}
+ * @implements {Iterable<T>}
  */
 export class YArray extends AbstractType {
   constructor () {
@@ -50,6 +50,25 @@ export class YArray extends AbstractType {
      * @private
      */
     this._prelimContent = []
+    /**
+     * @type {Array<ArraySearchMarker>}
+     */
+    this._searchMarker = []
+  }
+
+  /**
+   * Construct a new YArray containing the specified items.
+   * @template {Object<string,any>|Array<any>|number|null|string|Uint8Array} T
+   * @param {Array<T>} items
+   * @return {YArray<T>}
+   */
+  static from (items) {
+    /**
+     * @type {YArray<T>}
+     */
+    const a = new YArray()
+    a.push(items)
+    return a
   }
 
   /**
@@ -68,10 +87,27 @@ export class YArray extends AbstractType {
     this._prelimContent = null
   }
 
+  /**
+   * @return {YArray<T>}
+   */
   _copy () {
     return new YArray()
   }
 
+  /**
+   * @return {YArray<T>}
+   */
+  clone () {
+    /**
+     * @type {YArray<T>}
+     */
+    const arr = new YArray()
+    arr.insert(0, this.toArray().map(el =>
+      el instanceof AbstractType ? /** @type {typeof el} */ (el.clone()) : el
+    ))
+    return arr
+  }
+
   get length () {
     return this._prelimContent === null ? this._length : this._prelimContent.length
   }
@@ -83,6 +119,7 @@ export class YArray extends AbstractType {
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
    */
   _callObserver (transaction, parentSubs) {
+    super._callObserver(transaction, parentSubs)
     callTypeObservers(this, transaction, new YArrayEvent(this, transaction))
   }
 
@@ -105,7 +142,7 @@ export class YArray extends AbstractType {
   insert (index, content) {
     if (this.doc !== null) {
       transact(this.doc, transaction => {
-        typeListInsertGenerics(transaction, this, index, content)
+        typeListInsertGenerics(transaction, this, index, /** @type {any} */ (content))
       })
     } else {
       /** @type {Array<any>} */ (this._prelimContent).splice(index, 0, ...content)
@@ -116,9 +153,26 @@ export class YArray extends AbstractType {
    * Appends content to this YArray.
    *
    * @param {Array<T>} content Array of content to append.
+   *
+   * @todo Use the following implementation in all types.
    */
   push (content) {
-    this.insert(this.length, content)
+    if (this.doc !== null) {
+      transact(this.doc, transaction => {
+        typeListPushGenerics(transaction, this, /** @type {any} */ (content))
+      })
+    } else {
+      /** @type {Array<any>} */ (this._prelimContent).push(...content)
+    }
+  }
+
+  /**
+   * Preppends content to this YArray.
+   *
+   * @param {Array<T>} content Array of content to preppend.
+   */
+  unshift (content) {
+    this.insert(0, content)
   }
 
   /**
@@ -156,6 +210,17 @@ export class YArray extends AbstractType {
     return typeListToArray(this)
   }
 
+  /**
+   * Transforms this YArray to a JavaScript Array.
+   *
+   * @param {number} [start]
+   * @param {number} [end]
+   * @return {Array<T>}
+   */
+  slice (start = 0, end = this.length) {
+    return typeListSlice(this, start, end)
+  }
+
   /**
    * Transforms this Shared Type to a JSON object.
    *
@@ -169,7 +234,7 @@ export class YArray extends AbstractType {
    * Returns an Array with the result of calling a provided function on every
    * element of this YArray.
    *
-   * @template T,M
+   * @template M
    * @param {function(T,number,YArray<T>):M} f Function that produces an element of the new Array
    * @return {Array<M>} A new array with each element being the result of the
    *                 callback function
@@ -195,17 +260,17 @@ export class YArray extends AbstractType {
   }
 
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    */
   _write (encoder) {
-    encoding.writeVarUint(encoder, YArrayRefID)
+    encoder.writeTypeRef(YArrayRefID)
   }
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} _decoder
  *
  * @private
  * @function
  */
-export const readYArray = decoder => new YArray()
+export const readYArray = _decoder => new YArray()

src/types/YMap.js

@@ -14,15 +14,14 @@ import {
   YMapRefID,
   callTypeObservers,
   transact,
-  Doc, Transaction, Item // eslint-disable-line
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, Doc, Transaction, Item // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js' // eslint-disable-line
-import * as iterator from 'lib0/iterator.js'
+import * as iterator from 'lib0/iterator'
 
 /**
  * @template T
+ * @extends YEvent<YMap<T>>
  * Event that describes the changes on a YMap.
  */
 export class YMapEvent extends YEvent {
@@ -38,20 +37,30 @@ export class YMapEvent extends YEvent {
 }
 
 /**
- * @template T number|string|Object|Array|Uint8Array
+ * @template MapType
  * A shared Map implementation.
  *
- * @extends AbstractType<YMapEvent<T>>
- * @implements {IterableIterator}
+ * @extends AbstractType<YMapEvent<MapType>>
+ * @implements {Iterable<MapType>}
  */
 export class YMap extends AbstractType {
-  constructor () {
+  /**
+   *
+   * @param {Iterable<readonly [string, any]>=} entries - an optional iterable to initialize the YMap
+   */
+  constructor (entries) {
     super()
     /**
      * @type {Map<string,any>?}
      * @private
      */
-    this._prelimContent = new Map()
+    this._prelimContent = null
+
+    if (entries === undefined) {
+      this._prelimContent = new Map()
+    } else {
+      this._prelimContent = new Map(entries)
+    }
   }
 
   /**
@@ -66,16 +75,33 @@ export class YMap extends AbstractType {
    */
   _integrate (y, item) {
     super._integrate(y, item)
-    for (const [key, value] of /** @type {Map<string, any>} */ (this._prelimContent)) {
+    ;/** @type {Map<string, any>} */ (this._prelimContent).forEach((value, key) => {
       this.set(key, value)
-    }
+    })
     this._prelimContent = null
   }
 
+  /**
+   * @return {YMap<MapType>}
+   */
   _copy () {
     return new YMap()
   }
 
+  /**
+   * @return {YMap<MapType>}
+   */
+  clone () {
+    /**
+     * @type {YMap<MapType>}
+     */
+    const map = new YMap()
+    this.forEach((value, key) => {
+      map.set(key, value instanceof AbstractType ? /** @type {typeof value} */ (value.clone()) : value)
+    })
+    return map
+  }
+
   /**
    * Creates YMapEvent and calls observers.
    *
@@ -89,22 +115,31 @@ export class YMap extends AbstractType {
   /**
    * Transforms this Shared Type to a JSON object.
    *
-   * @return {Object<string,T>}
+   * @return {Object<string,any>}
    */
   toJSON () {
     /**
-     * @type {Object<string,T>}
+     * @type {Object<string,MapType>}
      */
     const map = {}
-    for (const [key, item] of this._map) {
+    this._map.forEach((item, key) => {
       if (!item.deleted) {
         const v = item.content.getContent()[item.length - 1]
         map[key] = v instanceof AbstractType ? v.toJSON() : v
       }
-    }
+    })
     return map
   }
 
+  /**
+   * Returns the size of the YMap (count of key/value pairs)
+   *
+   * @return {number}
+   */
+  get size () {
+    return [...createMapIterator(this._map)].length
+  }
+
   /**
    * Returns the keys for each element in the YMap Type.
    *
@@ -115,9 +150,9 @@ export class YMap extends AbstractType {
   }
 
   /**
-   * Returns the keys for each element in the YMap Type.
+   * Returns the values for each element in the YMap Type.
    *
-   * @return {IterableIterator<string>}
+   * @return {IterableIterator<any>}
    */
   values () {
     return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => v[1].content.getContent()[v[1].length - 1])
@@ -133,25 +168,22 @@ export class YMap extends AbstractType {
   }
 
   /**
-   * Executes a provided function on once on overy key-value pair.
+   * Executes a provided function on once on every key-value pair.
    *
-   * @param {function(T,string,YMap<T>):void} f A function to execute on every element of this YArray.
+   * @param {function(MapType,string,YMap<MapType>):void} f A function to execute on every element of this YArray.
    */
   forEach (f) {
-    /**
-     * @type {Object<string,T>}
-     */
-    const map = {}
-    for (const [key, item] of this._map) {
+    this._map.forEach((item, key) => {
       if (!item.deleted) {
         f(item.content.getContent()[item.length - 1], key, this)
       }
-    }
-    return map
+    })
   }
 
   /**
-   * @return {IterableIterator<T>}
+   * Returns an Iterator of [key, value] pairs
+   *
+   * @return {IterableIterator<any>}
    */
   [Symbol.iterator] () {
     return this.entries()
@@ -176,12 +208,12 @@ export class YMap extends AbstractType {
    * Adds or updates an element with a specified key and value.
    *
    * @param {string} key The key of the element to add to this YMap
-   * @param {T} value The value of the element to add
+   * @param {MapType} value The value of the element to add
    */
   set (key, value) {
     if (this.doc !== null) {
       transact(this.doc, transaction => {
-        typeMapSet(transaction, this, key, value)
+        typeMapSet(transaction, this, key, /** @type {any} */ (value))
       })
     } else {
       /** @type {Map<string, any>} */ (this._prelimContent).set(key, value)
@@ -193,7 +225,7 @@ export class YMap extends AbstractType {
    * Returns a specified element from this YMap.
    *
    * @param {string} key
-   * @return {T|undefined}
+   * @return {MapType|undefined}
    */
   get (key) {
     return /** @type {any} */ (typeMapGet(this, key))
@@ -210,17 +242,32 @@ export class YMap extends AbstractType {
   }
 
   /**
-   * @param {encoding.Encoder} encoder
+   * Removes all elements from this YMap.
+   */
+  clear () {
+    if (this.doc !== null) {
+      transact(this.doc, transaction => {
+        this.forEach(function (_value, key, map) {
+          typeMapDelete(transaction, map, key)
+        })
+      })
+    } else {
+      /** @type {Map<string, any>} */ (this._prelimContent).clear()
+    }
+  }
+
+  /**
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    */
   _write (encoder) {
-    encoding.writeVarUint(encoder, YMapRefID)
+    encoder.writeTypeRef(YMapRefID)
   }
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} _decoder
  *
  * @private
  * @function
  */
-export const readYMap = decoder => new YMap()
+export const readYMap = _decoder => new YMap()

src/types/YXmlElement.js

@@ -3,17 +3,15 @@ import {
   YXmlFragment,
   transact,
   typeMapDelete,
+  typeMapHas,
   typeMapSet,
   typeMapGet,
   typeMapGetAll,
   typeListForEach,
   YXmlElementRefID,
-  Snapshot, Doc, Item // eslint-disable-line
+  YXmlText, ContentType, AbstractType, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, Doc, Item // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
 /**
  * An YXmlElement imitates the behavior of a
  * {@link https://developer.mozilla.org/en-US/docs/Web/API/Element|Dom Element}.
@@ -31,6 +29,22 @@ export class YXmlElement extends YXmlFragment {
     this._prelimAttrs = new Map()
   }
 
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get nextSibling () {
+    const n = this._item ? this._item.next : null
+    return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
+  }
+
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get prevSibling () {
+    const n = this._item ? this._item.prev : null
+    return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
+  }
+
   /**
    * Integrate this type into the Yjs instance.
    *
@@ -58,6 +72,20 @@ export class YXmlElement extends YXmlFragment {
     return new YXmlElement(this.nodeName)
   }
 
+  /**
+   * @return {YXmlElement}
+   */
+  clone () {
+    const el = new YXmlElement(this.nodeName)
+    const attrs = this.getAttributes()
+    for (const key in attrs) {
+      el.setAttribute(key, attrs[key])
+    }
+    // @ts-ignore
+    el.insert(0, this.toArray().map(item => item instanceof AbstractType ? item.clone() : item))
+    return el
+  }
+
   /**
    * Returns the XML serialization of this YXmlElement.
    * The attributes are ordered by attribute-name, so you can easily use this
@@ -133,15 +161,26 @@ export class YXmlElement extends YXmlFragment {
     return /** @type {any} */ (typeMapGet(this, attributeName))
   }
 
+  /**
+   * Returns whether an attribute exists
+   *
+   * @param {String} attributeName The attribute name to check for existence.
+   * @return {boolean} whether the attribute exists.
+   *
+   * @public
+   */
+  hasAttribute (attributeName) {
+    return /** @type {any} */ (typeMapHas(this, attributeName))
+  }
+
   /**
    * Returns all attribute name/value pairs in a JSON Object.
    *
-   * @param {Snapshot} [snapshot]
    * @return {Object<string, any>} A JSON Object that describes the attributes.
    *
    * @public
    */
-  getAttributes (snapshot) {
+  getAttributes () {
     return typeMapGetAll(this)
   }
 
@@ -181,18 +220,18 @@ export class YXmlElement extends YXmlFragment {
    *
    * This is called when this Item is sent to a remote peer.
    *
-   * @param {encoding.Encoder} encoder The encoder to write data to.
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
    */
   _write (encoder) {
-    encoding.writeVarUint(encoder, YXmlElementRefID)
-    encoding.writeVarString(encoder, this.nodeName)
+    encoder.writeTypeRef(YXmlElementRefID)
+    encoder.writeKey(this.nodeName)
   }
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {YXmlElement}
  *
  * @function
  */
-export const readYXmlElement = decoder => new YXmlElement(decoding.readVarString(decoder))
+export const readYXmlElement = decoder => new YXmlElement(decoder.readKey())

src/types/YXmlEvent.js

@@ -1,15 +1,16 @@
 
 import {
   YEvent,
-  YXmlElement, YXmlFragment, Transaction // eslint-disable-line
+  YXmlText, YXmlElement, YXmlFragment, Transaction // eslint-disable-line
 } from '../internals.js'
 
 /**
+ * @extends YEvent<YXmlElement|YXmlText|YXmlFragment>
  * An Event that describes changes on a YXml Element or Yxml Fragment
  */
 export class YXmlEvent extends YEvent {
   /**
-   * @param {YXmlElement|YXmlFragment} target The target on which the event is created.
+   * @param {YXmlElement|YXmlText|YXmlFragment} target The target on which the event is created.
    * @param {Set<string|null>} subs The set of changed attributes. `null` is included if the
    *                   child list changed.
    * @param {Transaction} transaction The transaction instance with wich the
@@ -25,7 +26,7 @@ export class YXmlEvent extends YEvent {
     this.childListChanged = false
     /**
      * Set of all changed attributes.
-     * @type {Set<string|null>}
+     * @type {Set<string>}
      */
     this.attributesChanged = new Set()
     subs.forEach((sub) => {

src/types/YXmlFragment.js

@@ -9,16 +9,19 @@ import {
   typeListMap,
   typeListForEach,
   typeListInsertGenerics,
+  typeListInsertGenericsAfter,
   typeListDelete,
   typeListToArray,
   YXmlFragmentRefID,
   callTypeObservers,
   transact,
-  Doc, ContentType, Transaction, Item, YXmlText, YXmlHook, Snapshot // eslint-disable-line
+  typeListGet,
+  typeListSlice,
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, Doc, ContentType, Transaction, Item, YXmlText, YXmlHook // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js' // eslint-disable-line
+import * as error from 'lib0/error'
+import * as array from 'lib0/array'
 
 /**
  * Define the elements to which a set of CSS queries apply.
@@ -48,7 +51,7 @@ import * as decoding from 'lib0/decoding.js' // eslint-disable-line
  * Can be created with {@link YXmlFragment#createTreeWalker}
  *
  * @public
- * @implements {IterableIterator}
+ * @implements {Iterable<YXmlElement|YXmlText|YXmlElement|YXmlHook>}
  */
 export class YXmlTreeWalker {
   /**
@@ -81,10 +84,10 @@ export class YXmlTreeWalker {
      * @type {Item|null}
      */
     let n = this._currentNode
-    let type = /** @type {ContentType} */ (n.content).type
+    let type = n && n.content && /** @type {any} */ (n.content).type
     if (n !== null && (!this._firstCall || n.deleted || !this._filter(type))) { // if first call, we check if we can use the first item
       do {
-        type = /** @type {ContentType} */ (n.content).type
+        type = /** @type {any} */ (n.content).type
         if (!n.deleted && (type.constructor === YXmlElement || type.constructor === YXmlFragment) && type._start !== null) {
           // walk down in the tree
           n = type._start
@@ -97,7 +100,7 @@ export class YXmlTreeWalker {
             } else if (n.parent === this._root) {
               n = null
             } else {
-              n = n.parent._item
+              n = /** @type {AbstractType<any>} */ (n.parent)._item
             }
           }
         }
@@ -131,6 +134,14 @@ export class YXmlFragment extends AbstractType {
     this._prelimContent = []
   }
 
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get firstChild () {
+    const first = this._first
+    return first ? first.content.getContent()[0] : null
+  }
+
   /**
    * Integrate this type into the Yjs instance.
    *
@@ -151,6 +162,16 @@ export class YXmlFragment extends AbstractType {
     return new YXmlFragment()
   }
 
+  /**
+   * @return {YXmlFragment}
+   */
+  clone () {
+    const el = new YXmlFragment()
+    // @ts-ignore
+    el.insert(0, this.toArray().map(item => item instanceof AbstractType ? item.clone() : item))
+    return el
+  }
+
   get length () {
     return this._prelimContent === null ? this._length : this._prelimContent.length
   }
@@ -217,7 +238,7 @@ export class YXmlFragment extends AbstractType {
   querySelectorAll (query) {
     query = query.toUpperCase()
     // @ts-ignore
-    return Array.from(new YXmlTreeWalker(this, element => element.nodeName && element.nodeName.toUpperCase() === query))
+    return array.from(new YXmlTreeWalker(this, element => element.nodeName && element.nodeName.toUpperCase() === query))
   }
 
   /**
@@ -293,6 +314,32 @@ export class YXmlFragment extends AbstractType {
     }
   }
 
+  /**
+   * Inserts new content at an index.
+   *
+   * @example
+   *  // Insert character 'a' at position 0
+   *  xml.insert(0, [new Y.XmlText('text')])
+   *
+   * @param {null|Item|YXmlElement|YXmlText} ref The index to insert content at
+   * @param {Array<YXmlElement|YXmlText>} content The array of content
+   */
+  insertAfter (ref, content) {
+    if (this.doc !== null) {
+      transact(this.doc, transaction => {
+        const refItem = (ref && ref instanceof AbstractType) ? ref._item : ref
+        typeListInsertGenericsAfter(transaction, this, refItem, content)
+      })
+    } else {
+      const pc = /** @type {Array<any>} */ (this._prelimContent)
+      const index = ref === null ? 0 : pc.findIndex(el => el === ref) + 1
+      if (index === 0 && ref !== null) {
+        throw error.create('Reference item not found')
+      }
+      pc.splice(index, 0, ...content)
+    }
+  }
+
   /**
    * Deletes elements starting from an index.
    *
@@ -319,24 +366,72 @@ export class YXmlFragment extends AbstractType {
     return typeListToArray(this)
   }
 
+  /**
+   * Appends content to this YArray.
+   *
+   * @param {Array<YXmlElement|YXmlText>} content Array of content to append.
+   */
+  push (content) {
+    this.insert(this.length, content)
+  }
+
+  /**
+   * Preppends content to this YArray.
+   *
+   * @param {Array<YXmlElement|YXmlText>} content Array of content to preppend.
+   */
+  unshift (content) {
+    this.insert(0, content)
+  }
+
+  /**
+   * Returns the i-th element from a YArray.
+   *
+   * @param {number} index The index of the element to return from the YArray
+   * @return {YXmlElement|YXmlText}
+   */
+  get (index) {
+    return typeListGet(this, index)
+  }
+
+  /**
+   * Transforms this YArray to a JavaScript Array.
+   *
+   * @param {number} [start]
+   * @param {number} [end]
+   * @return {Array<YXmlElement|YXmlText>}
+   */
+  slice (start = 0, end = this.length) {
+    return typeListSlice(this, start, end)
+  }
+
+  /**
+   * Executes a provided function on once on overy child element.
+   *
+   * @param {function(YXmlElement|YXmlText,number, typeof self):void} f A function to execute on every element of this YArray.
+   */
+  forEach (f) {
+    typeListForEach(this, f)
+  }
+
   /**
    * Transform the properties of this type to binary and write it to an
    * BinaryEncoder.
    *
    * This is called when this Item is sent to a remote peer.
    *
-   * @param {encoding.Encoder} encoder The encoder to write data to.
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
    */
   _write (encoder) {
-    encoding.writeVarUint(encoder, YXmlFragmentRefID)
+    encoder.writeTypeRef(YXmlFragmentRefID)
   }
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} _decoder
  * @return {YXmlFragment}
  *
  * @private
  * @function
  */
-export const readYXmlFragment = decoder => new YXmlFragment()
+export const readYXmlFragment = _decoder => new YXmlFragment()

src/types/YXmlHook.js

@@ -1,10 +1,9 @@
 
 import {
   YMap,
-  YXmlHookRefID
+  YXmlHookRefID,
+  UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2 // eslint-disable-line
 } from '../internals.js'
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
 
 /**
  * You can manage binding to a custom type with YXmlHook.
@@ -30,6 +29,17 @@ export class YXmlHook extends YMap {
     return new YXmlHook(this.hookName)
   }
 
+  /**
+   * @return {YXmlHook}
+   */
+  clone () {
+    const el = new YXmlHook(this.hookName)
+    this.forEach((value, key) => {
+      el.set(key, value)
+    })
+    return el
+  }
+
   /**
    * Creates a Dom Element that mirrors this YXmlElement.
    *
@@ -66,21 +76,20 @@ export class YXmlHook extends YMap {
    *
    * This is called when this Item is sent to a remote peer.
    *
-   * @param {encoding.Encoder} encoder The encoder to write data to.
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder The encoder to write data to.
    */
   _write (encoder) {
-    super._write(encoder)
-    encoding.writeVarUint(encoder, YXmlHookRefID)
-    encoding.writeVarString(encoder, this.hookName)
+    encoder.writeTypeRef(YXmlHookRefID)
+    encoder.writeKey(this.hookName)
   }
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {YXmlHook}
  *
  * @private
  * @function
  */
 export const readYXmlHook = decoder =>
-  new YXmlHook(decoding.readVarString(decoder))
+  new YXmlHook(decoder.readKey())

src/types/YXmlText.js

@@ -1,18 +1,44 @@
 
-import { YText, YXmlTextRefID } from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js' // eslint-disable-line
+import {
+  YText,
+  YXmlTextRefID,
+  ContentType, YXmlElement, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2, // eslint-disable-line
+} from '../internals.js'
 
 /**
  * Represents text in a Dom Element. In the future this type will also handle
  * simple formatting information like bold and italic.
  */
 export class YXmlText extends YText {
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get nextSibling () {
+    const n = this._item ? this._item.next : null
+    return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
+  }
+
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get prevSibling () {
+    const n = this._item ? this._item.prev : null
+    return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
+  }
+
   _copy () {
     return new YXmlText()
   }
 
+  /**
+   * @return {YXmlText}
+   */
+  clone () {
+    const text = new YXmlText()
+    text.applyDelta(this.toDelta())
+    return text
+  }
+
   /**
    * Creates a Dom Element that mirrors this YXmlText.
    *
@@ -78,15 +104,15 @@ export class YXmlText extends YText {
   }
 
   /**
-   * @param {encoding.Encoder} encoder
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
    */
   _write (encoder) {
-    encoding.writeVarUint(encoder, YXmlTextRefID)
+    encoder.writeTypeRef(YXmlTextRefID)
   }
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
  * @return {YXmlText}
  *
  * @private

src/utils/AbstractConnector.js

@@ -0,0 +1,26 @@
+
+import { Observable } from 'lib0/observable'
+
+import {
+  Doc // eslint-disable-line
+} from '../internals.js'
+
+/**
+ * This is an abstract interface that all Connectors should implement to keep them interchangeable.
+ *
+ * @note This interface is experimental and it is not advised to actually inherit this class.
+ *       It just serves as typing information.
+ *
+ * @extends {Observable<any>}
+ */
+export class AbstractConnector extends Observable {
+  /**
+   * @param {Doc} ydoc
+   * @param {any} awareness
+   */
+  constructor (ydoc, awareness) {
+    super()
+    this.doc = ydoc
+    this.awareness = awareness
+  }
+}

src/utils/DeleteSet.js

@@ -1,18 +1,18 @@
 
 import {
   findIndexSS,
-  createID,
   getState,
   splitItem,
   iterateStructs,
-  Item, GC, StructStore, Transaction, ID // eslint-disable-line
+  UpdateEncoderV2,
+  DSDecoderV1, DSEncoderV1, DSDecoderV2, DSEncoderV2, Item, GC, StructStore, Transaction, ID // eslint-disable-line
 } from '../internals.js'
 
-import * as array from 'lib0/array.js'
-import * as math from 'lib0/math.js'
-import * as map from 'lib0/map.js'
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
+import * as array from 'lib0/array'
+import * as math from 'lib0/math'
+import * as map from 'lib0/map'
+import * as encoding from 'lib0/encoding'
+import * as decoding from 'lib0/decoding'
 
 export class DeleteItem {
   /**
@@ -122,8 +122,8 @@ export const sortAndMergeDeleteSet = ds => {
     for (i = 1, j = 1; i < dels.length; i++) {
       const left = dels[j - 1]
       const right = dels[i]
-      if (left.clock + left.len === right.clock) {
-        left.len += right.len
+      if (left.clock + left.len >= right.clock) {
+        left.len = math.max(left.len, right.clock + right.len - left.clock)
       } else {
         if (j < i) {
           dels[j] = right
@@ -163,14 +163,15 @@ export const mergeDeleteSets = dss => {
 
 /**
  * @param {DeleteSet} ds
- * @param {ID} id
+ * @param {number} client
+ * @param {number} clock
  * @param {number} length
  *
  * @private
  * @function
  */
-export const addToDeleteSet = (ds, id, length) => {
-  map.setIfUndefined(ds.clients, id.client, () => []).push(new DeleteItem(id.clock, length))
+export const addToDeleteSet = (ds, client, clock, length) => {
+  map.setIfUndefined(ds.clients, client, () => []).push(new DeleteItem(clock, length))
 }
 
 export const createDeleteSet = () => new DeleteSet()
@@ -195,7 +196,7 @@ export const createDeleteSetFromStructStore = ss => {
         const clock = struct.id.clock
         let len = struct.length
         if (i + 1 < structs.length) {
-          for (let next = structs[i + 1]; i + 1 < structs.length && next.id.clock === clock + len && next.deleted; next = structs[++i + 1]) {
+          for (let next = structs[i + 1]; i + 1 < structs.length && next.deleted; next = structs[++i + 1]) {
             len += next.length
           }
         }
@@ -210,28 +211,33 @@ export const createDeleteSetFromStructStore = ss => {
 }
 
 /**
- * @param {encoding.Encoder} encoder
+ * @param {DSEncoderV1 | DSEncoderV2} encoder
  * @param {DeleteSet} ds
  *
  * @private
  * @function
  */
 export const writeDeleteSet = (encoder, ds) => {
-  encoding.writeVarUint(encoder, ds.clients.size)
-  ds.clients.forEach((dsitems, client) => {
-    encoding.writeVarUint(encoder, client)
-    const len = dsitems.length
-    encoding.writeVarUint(encoder, len)
-    for (let i = 0; i < len; i++) {
-      const item = dsitems[i]
-      encoding.writeVarUint(encoder, item.clock)
-      encoding.writeVarUint(encoder, item.len)
-    }
-  })
+  encoding.writeVarUint(encoder.restEncoder, ds.clients.size)
+
+  // Ensure that the delete set is written in a deterministic order
+  array.from(ds.clients.entries())
+    .sort((a, b) => b[0] - a[0])
+    .forEach(([client, dsitems]) => {
+      encoder.resetDsCurVal()
+      encoding.writeVarUint(encoder.restEncoder, client)
+      const len = dsitems.length
+      encoding.writeVarUint(encoder.restEncoder, len)
+      for (let i = 0; i < len; i++) {
+        const item = dsitems[i]
+        encoder.writeDsClock(item.clock)
+        encoder.writeDsLen(item.len)
+      }
+    })
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @param {DSDecoderV1 | DSDecoderV2} decoder
  * @return {DeleteSet}
  *
  * @private
@@ -239,39 +245,49 @@ export const writeDeleteSet = (encoder, ds) => {
  */
 export const readDeleteSet = decoder => {
   const ds = new DeleteSet()
-  const numClients = decoding.readVarUint(decoder)
+  const numClients = decoding.readVarUint(decoder.restDecoder)
   for (let i = 0; i < numClients; i++) {
-    const client = decoding.readVarUint(decoder)
-    const numberOfDeletes = decoding.readVarUint(decoder)
-    for (let i = 0; i < numberOfDeletes; i++) {
-      addToDeleteSet(ds, createID(client, decoding.readVarUint(decoder)), decoding.readVarUint(decoder))
+    decoder.resetDsCurVal()
+    const client = decoding.readVarUint(decoder.restDecoder)
+    const numberOfDeletes = decoding.readVarUint(decoder.restDecoder)
+    if (numberOfDeletes > 0) {
+      const dsField = map.setIfUndefined(ds.clients, client, () => [])
+      for (let i = 0; i < numberOfDeletes; i++) {
+        dsField.push(new DeleteItem(decoder.readDsClock(), decoder.readDsLen()))
+      }
     }
   }
   return ds
 }
 
 /**
- * @param {decoding.Decoder} decoder
+ * @todo YDecoder also contains references to String and other Decoders. Would make sense to exchange YDecoder.toUint8Array for YDecoder.DsToUint8Array()..
+ */
+
+/**
+ * @param {DSDecoderV1 | DSDecoderV2} decoder
  * @param {Transaction} transaction
  * @param {StructStore} store
+ * @return {Uint8Array|null} Returns a v2 update containing all deletes that couldn't be applied yet; or null if all deletes were applied successfully.
  *
  * @private
  * @function
  */
 export const readAndApplyDeleteSet = (decoder, transaction, store) => {
   const unappliedDS = new DeleteSet()
-  const numClients = decoding.readVarUint(decoder)
+  const numClients = decoding.readVarUint(decoder.restDecoder)
   for (let i = 0; i < numClients; i++) {
-    const client = decoding.readVarUint(decoder)
-    const numberOfDeletes = decoding.readVarUint(decoder)
+    decoder.resetDsCurVal()
+    const client = decoding.readVarUint(decoder.restDecoder)
+    const numberOfDeletes = decoding.readVarUint(decoder.restDecoder)
     const structs = store.clients.get(client) || []
     const state = getState(store, client)
     for (let i = 0; i < numberOfDeletes; i++) {
-      const clock = decoding.readVarUint(decoder)
-      const len = decoding.readVarUint(decoder)
+      const clock = decoder.readDsClock()
+      const clockEnd = clock + decoder.readDsLen()
       if (clock < state) {
-        if (state < clock + len) {
-          addToDeleteSet(unappliedDS, createID(client, state), clock + len - state)
+        if (state < clockEnd) {
+          addToDeleteSet(unappliedDS, client, state, clockEnd - state)
         }
         let index = findIndexSS(structs, clock)
         /**
@@ -288,10 +304,10 @@ export const readAndApplyDeleteSet = (decoder, transaction, store) => {
         while (index < structs.length) {
           // @ts-ignore
           struct = structs[index++]
-          if (struct.id.clock < clock + len) {
+          if (struct.id.clock < clockEnd) {
             if (!struct.deleted) {
-              if (clock + len < struct.id.clock + struct.length) {
-                structs.splice(index, 0, splitItem(transaction, struct, clock + len - struct.id.clock))
+              if (clockEnd < struct.id.clock + struct.length) {
+                structs.splice(index, 0, splitItem(transaction, struct, clockEnd - struct.id.clock))
               }
               struct.delete(transaction)
             }
@@ -300,14 +316,15 @@ export const readAndApplyDeleteSet = (decoder, transaction, store) => {
           }
         }
       } else {
-        addToDeleteSet(unappliedDS, createID(client, clock), len)
+        addToDeleteSet(unappliedDS, client, clock, clockEnd - clock)
       }
     }
   }
   if (unappliedDS.clients.size > 0) {
-    // TODO: no need for encoding+decoding ds anymore
-    const unappliedDSEncoder = encoding.createEncoder()
-    writeDeleteSet(unappliedDSEncoder, unappliedDS)
-    store.pendingDeleteReaders.push(decoding.createDecoder(encoding.toUint8Array(unappliedDSEncoder)))
+    const ds = new UpdateEncoderV2()
+    encoding.writeVarUint(ds.restEncoder, 0) // encode 0 structs
+    writeDeleteSet(ds, unappliedDS)
+    return ds.toUint8Array()
   }
+  return null
 }

src/utils/Doc.js

@@ -10,32 +10,45 @@ import {
   YMap,
   YXmlFragment,
   transact,
-  Item, Transaction, YEvent // eslint-disable-line
+  ContentDoc, Item, Transaction, YEvent // eslint-disable-line
 } from '../internals.js'
 
-import { Observable } from 'lib0/observable.js'
-import * as random from 'lib0/random.js'
-import * as map from 'lib0/map.js'
+import { Observable } from 'lib0/observable'
+import * as random from 'lib0/random'
+import * as map from 'lib0/map'
+import * as array from 'lib0/array'
+import * as promise from 'lib0/promise'
 
 export const generateNewClientId = random.uint32
 
+/**
+ * @typedef {Object} DocOpts
+ * @property {boolean} [DocOpts.gc=true] Disable garbage collection (default: gc=true)
+ * @property {function(Item):boolean} [DocOpts.gcFilter] Will be called before an Item is garbage collected. Return false to keep the Item.
+ * @property {string} [DocOpts.guid] Define a globally unique identifier for this document
+ * @property {string | null} [DocOpts.collectionid] Associate this document with a collection. This only plays a role if your provider has a concept of collection.
+ * @property {any} [DocOpts.meta] Any kind of meta information you want to associate with this document. If this is a subdocument, remote peers will store the meta information as well.
+ * @property {boolean} [DocOpts.autoLoad] If a subdocument, automatically load document. If this is a subdocument, remote peers will load the document as well automatically.
+ * @property {boolean} [DocOpts.shouldLoad] Whether the document should be synced by the provider now. This is toggled to true when you call ydoc.load()
+ */
+
 /**
  * A Yjs instance handles the state of shared data.
  * @extends Observable<string>
  */
 export class Doc extends Observable {
   /**
-   * @param {Object} conf configuration
-   * @param {boolean} [conf.gc] Disable garbage collection (default: gc=true)
-   * @param {function(Item):boolean} [conf.gcFilter] Will be called before an Item is garbage collected. Return false to keep the Item.
+   * @param {DocOpts} opts configuration
    */
-  constructor ({ gc = true, gcFilter = () => true } = {}) {
+  constructor ({ guid = random.uuidv4(), collectionid = null, gc = true, gcFilter = () => true, meta = null, autoLoad = false, shouldLoad = true } = {}) {
     super()
     this.gc = gc
     this.gcFilter = gcFilter
     this.clientID = generateNewClientId()
+    this.guid = guid
+    this.collectionid = collectionid
     /**
-     * @type {Map<string, AbstractType<YEvent>>}
+     * @type {Map<string, AbstractType<YEvent<any>>>}
      */
     this.share = new Map()
     this.store = new StructStore()
@@ -47,6 +60,94 @@ export class Doc extends Observable {
      * @type {Array<Transaction>}
      */
     this._transactionCleanups = []
+    /**
+     * @type {Set<Doc>}
+     */
+    this.subdocs = new Set()
+    /**
+     * If this document is a subdocument - a document integrated into another document - then _item is defined.
+     * @type {Item?}
+     */
+    this._item = null
+    this.shouldLoad = shouldLoad
+    this.autoLoad = autoLoad
+    this.meta = meta
+    /**
+     * This is set to true when the persistence provider loaded the document from the database or when the `sync` event fires.
+     * Note that not all providers implement this feature. Provider authors are encouraged to fire the `load` event when the doc content is loaded from the database.
+     *
+     * @type {boolean}
+     */
+    this.isLoaded = false
+    /**
+     * This is set to true when the connection provider has successfully synced with a backend.
+     * Note that when using peer-to-peer providers this event may not provide very useful.
+     * Also note that not all providers implement this feature. Provider authors are encouraged to fire
+     * the `sync` event when the doc has been synced (with `true` as a parameter) or if connection is
+     * lost (with false as a parameter).
+     */
+    this.isSynced = false
+    /**
+     * Promise that resolves once the document has been loaded from a presistence provider.
+     */
+    this.whenLoaded = promise.create(resolve => {
+      this.on('load', () => {
+        this.isLoaded = true
+        resolve(this)
+      })
+    })
+    const provideSyncedPromise = () => promise.create(resolve => {
+      /**
+       * @param {boolean} isSynced
+       */
+      const eventHandler = (isSynced) => {
+        if (isSynced === undefined || isSynced === true) {
+          this.off('sync', eventHandler)
+          resolve()
+        }
+      }
+      this.on('sync', eventHandler)
+    })
+    this.on('sync', isSynced => {
+      if (isSynced === false && this.isSynced) {
+        this.whenSynced = provideSyncedPromise()
+      }
+      this.isSynced = isSynced === undefined || isSynced === true
+      if (!this.isLoaded) {
+        this.emit('load', [])
+      }
+    })
+    /**
+     * Promise that resolves once the document has been synced with a backend.
+     * This promise is recreated when the connection is lost.
+     * Note the documentation about the `isSynced` property.
+     */
+    this.whenSynced = provideSyncedPromise()
+  }
+
+  /**
+   * Notify the parent document that you request to load data into this subdocument (if it is a subdocument).
+   *
+   * `load()` might be used in the future to request any provider to load the most current data.
+   *
+   * It is safe to call `load()` multiple times.
+   */
+  load () {
+    const item = this._item
+    if (item !== null && !this.shouldLoad) {
+      transact(/** @type {any} */ (item.parent).doc, transaction => {
+        transaction.subdocsLoaded.add(this)
+      }, null, true)
+    }
+    this.shouldLoad = true
+  }
+
+  getSubdocs () {
+    return this.subdocs
+  }
+
+  getSubdocGuids () {
+    return new Set(array.from(this.subdocs).map(doc => doc.guid))
   }
 
   /**
@@ -126,60 +227,98 @@ export class Doc extends Observable {
 
   /**
    * @template T
-   * @param {string} name
+   * @param {string} [name]
    * @return {YArray<T>}
    *
    * @public
    */
-  getArray (name) {
+  getArray (name = '') {
     // @ts-ignore
     return this.get(name, YArray)
   }
 
   /**
-   * @param {string} name
+   * @param {string} [name]
    * @return {YText}
    *
    * @public
    */
-  getText (name) {
+  getText (name = '') {
     // @ts-ignore
     return this.get(name, YText)
   }
 
   /**
-   * @param {string} name
-   * @return {YMap<any>}
+   * @template T
+   * @param {string} [name]
+   * @return {YMap<T>}
    *
    * @public
    */
-  getMap (name) {
+  getMap (name = '') {
     // @ts-ignore
     return this.get(name, YMap)
   }
 
   /**
-   * @param {string} name
+   * @param {string} [name]
    * @return {YXmlFragment}
    *
    * @public
    */
-  getXmlFragment (name) {
+  getXmlFragment (name = '') {
     // @ts-ignore
     return this.get(name, YXmlFragment)
   }
 
+  /**
+   * Converts the entire document into a js object, recursively traversing each yjs type
+   * Doesn't log types that have not been defined (using ydoc.getType(..)).
+   *
+   * @deprecated Do not use this method and rather call toJSON directly on the shared types.
+   *
+   * @return {Object<string, any>}
+   */
+  toJSON () {
+    /**
+     * @type {Object<string, any>}
+     */
+    const doc = {}
+
+    this.share.forEach((value, key) => {
+      doc[key] = value.toJSON()
+    })
+
+    return doc
+  }
+
   /**
    * Emit `destroy` event and unregister all event handlers.
    */
   destroy () {
+    array.from(this.subdocs).forEach(subdoc => subdoc.destroy())
+    const item = this._item
+    if (item !== null) {
+      this._item = null
+      const content = /** @type {ContentDoc} */ (item.content)
+      content.doc = new Doc({ guid: this.guid, ...content.opts, shouldLoad: false })
+      content.doc._item = item
+      transact(/** @type {any} */ (item).parent.doc, transaction => {
+        const doc = content.doc
+        if (!item.deleted) {
+          transaction.subdocsAdded.add(doc)
+        }
+        transaction.subdocsRemoved.add(this)
+      }, null, true)
+    }
     this.emit('destroyed', [true])
+    this.emit('destroy', [this])
     super.destroy()
   }
 
   /**
    * @param {string} eventName
-   * @param {function} f
+   * @param {function(...any):any} f
    */
   on (eventName, f) {
     super.on(eventName, f)

src/utils/EventHandler.js

@@ -1,4 +1,4 @@
-import * as f from 'lib0/function.js'
+import * as f from 'lib0/function'
 
 /**
  * General event handler implementation.
@@ -51,7 +51,12 @@ export const addEventHandlerListener = (eventHandler, f) =>
  * @function
  */
 export const removeEventHandlerListener = (eventHandler, f) => {
-  eventHandler.l = eventHandler.l.filter(g => f !== g)
+  const l = eventHandler.l
+  const len = l.length
+  eventHandler.l = l.filter(g => f !== g)
+  if (len === eventHandler.l.length) {
+    console.error('[yjs] Tried to remove event handler that doesn\'t exist.')
+  }
 }
 
 /**

src/utils/ID.js

@@ -1,9 +1,9 @@
 
 import { AbstractType } from '../internals.js' // eslint-disable-line
 
-import * as decoding from 'lib0/decoding.js'
-import * as encoding from 'lib0/encoding.js'
-import * as error from 'lib0/error.js'
+import * as decoding from 'lib0/decoding'
+import * as encoding from 'lib0/encoding'
+import * as error from 'lib0/error'
 
 export class ID {
   /**
@@ -81,7 +81,7 @@ export const readID = decoder =>
  */
 export const findRootTypeKey = type => {
   // @ts-ignore _y must be defined, otherwise unexpected case
-  for (const [key, value] of type.doc.share) {
+  for (const [key, value] of type.doc.share.entries()) {
     if (value === type) {
       return key
     }

src/utils/PermanentUserData.js

@@ -5,11 +5,11 @@ import {
   readDeleteSet,
   writeDeleteSet,
   createDeleteSet,
-  ID, DeleteSet, YArrayEvent, Transaction, Doc // eslint-disable-line
+  DSEncoderV1, DSDecoderV1, ID, DeleteSet, YArrayEvent, Transaction, Doc // eslint-disable-line
 } from '../internals.js'
 
-import * as decoding from 'lib0/decoding.js'
-import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding'
+
 import { mergeDeleteSets, isDeleted } from './DeleteSet.js'
 
 export class PermanentUserData {
@@ -46,12 +46,12 @@ export class PermanentUserData {
         event.changes.added.forEach(item => {
           item.content.getContent().forEach(encodedDs => {
             if (encodedDs instanceof Uint8Array) {
-              this.dss.set(userDescription, mergeDeleteSets([this.dss.get(userDescription) || createDeleteSet(), readDeleteSet(decoding.createDecoder(encodedDs))]))
+              this.dss.set(userDescription, mergeDeleteSets([this.dss.get(userDescription) || createDeleteSet(), readDeleteSet(new DSDecoderV1(decoding.createDecoder(encodedDs)))]))
             }
           })
         })
       })
-      this.dss.set(userDescription, mergeDeleteSets(ds.map(encodedDs => readDeleteSet(decoding.createDecoder(encodedDs)))))
+      this.dss.set(userDescription, mergeDeleteSets(ds.map(encodedDs => readDeleteSet(new DSDecoderV1(decoding.createDecoder(encodedDs))))))
       ids.observe(/** @param {YArrayEvent<any>} event */ event =>
         event.changes.added.forEach(item => item.content.getContent().forEach(addClientId))
       )
@@ -71,7 +71,7 @@ export class PermanentUserData {
    * @param {Doc} doc
    * @param {number} clientid
    * @param {string} userDescription
-   * @param {Object} [conf]
+   * @param {Object} conf
    * @param {function(Transaction, DeleteSet):boolean} [conf.filter]
    */
   setUserMapping (doc, clientid, userDescription, { filter = () => true } = {}) {
@@ -84,7 +84,7 @@ export class PermanentUserData {
       users.set(userDescription, user)
     }
     user.get('ids').push([clientid])
-    users.observe(event => {
+    users.observe(_event => {
       setTimeout(() => {
         const userOverwrite = users.get(userDescription)
         if (userOverwrite !== user) {
@@ -97,11 +97,11 @@ export class PermanentUserData {
               user.get('ids').push([clientid])
             }
           })
-          const encoder = encoding.createEncoder()
+          const encoder = new DSEncoderV1()
           const ds = this.dss.get(userDescription)
           if (ds) {
             writeDeleteSet(encoder, ds)
-            user.get('ds').push([encoding.toUint8Array(encoder)])
+            user.get('ds').push([encoder.toUint8Array()])
           }
         }
       }, 0)
@@ -111,9 +111,9 @@ export class PermanentUserData {
         const yds = user.get('ds')
         const ds = transaction.deleteSet
         if (transaction.local && ds.clients.size > 0 && filter(transaction, ds)) {
-          const encoder = encoding.createEncoder()
+          const encoder = new DSEncoderV1()
           writeDeleteSet(encoder, ds)
-          yds.push([encoding.toUint8Array(encoder)])
+          yds.push([encoder.toUint8Array()])
         }
       })
     })
@@ -132,7 +132,7 @@ export class PermanentUserData {
    * @return {string | null}
    */
   getUserByDeletedId (id) {
-    for (const [userDescription, ds] of this.dss) {
+    for (const [userDescription, ds] of this.dss.entries()) {
       if (isDeleted(ds, id)) {
         return userDescription
       }

src/utils/RelativePosition.js

@@ -1,20 +1,20 @@
 
 import {
-  createID,
   writeID,
   readID,
   compareIDs,
   getState,
   findRootTypeKey,
   Item,
+  createID,
   ContentType,
   followRedone,
   ID, Doc, AbstractType // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-import * as error from 'lib0/error.js'
+import * as encoding from 'lib0/encoding'
+import * as decoding from 'lib0/decoding'
+import * as error from 'lib0/error'
 
 /**
  * A relative position is based on the Yjs model and is not affected by document changes.
@@ -45,8 +45,9 @@ export class RelativePosition {
    * @param {ID|null} type
    * @param {string|null} tname
    * @param {ID|null} item
+   * @param {number} assoc
    */
-  constructor (type, tname, item) {
+  constructor (type, tname, item, assoc = 0) {
     /**
      * @type {ID|null}
      */
@@ -59,23 +60,57 @@ export class RelativePosition {
      * @type {ID | null}
      */
     this.item = item
+    /**
+     * A relative position is associated to a specific character. By default
+     * assoc >= 0, the relative position is associated to the character
+     * after the meant position.
+     * I.e. position 1 in 'ab' is associated to character 'b'.
+     *
+     * If assoc < 0, then the relative position is associated to the caharacter
+     * before the meant position.
+     *
+     * @type {number}
+     */
+    this.assoc = assoc
   }
 }
 
+/**
+ * @param {RelativePosition} rpos
+ * @return {any}
+ */
+export const relativePositionToJSON = rpos => {
+  const json = {}
+  if (rpos.type) {
+    json.type = rpos.type
+  }
+  if (rpos.tname) {
+    json.tname = rpos.tname
+  }
+  if (rpos.item) {
+    json.item = rpos.item
+  }
+  if (rpos.assoc != null) {
+    json.assoc = rpos.assoc
+  }
+  return json
+}
+
 /**
  * @param {any} json
  * @return {RelativePosition}
  *
  * @function
  */
-export const createRelativePositionFromJSON = json => new RelativePosition(json.type == null ? null : createID(json.type.client, json.type.clock), json.tname || null, json.item == null ? null : createID(json.item.client, json.item.clock))
+export const createRelativePositionFromJSON = json => new RelativePosition(json.type == null ? null : createID(json.type.client, json.type.clock), json.tname || null, json.item == null ? null : createID(json.item.client, json.item.clock), json.assoc == null ? 0 : json.assoc)
 
 export class AbsolutePosition {
   /**
    * @param {AbstractType<any>} type
    * @param {number} index
+   * @param {number} [assoc]
    */
-  constructor (type, index) {
+  constructor (type, index, assoc = 0) {
     /**
      * @type {AbstractType<any>}
      */
@@ -84,32 +119,35 @@ export class AbsolutePosition {
      * @type {number}
      */
     this.index = index
+    this.assoc = assoc
   }
 }
 
 /**
  * @param {AbstractType<any>} type
  * @param {number} index
+ * @param {number} [assoc]
  *
  * @function
  */
-export const createAbsolutePosition = (type, index) => new AbsolutePosition(type, index)
+export const createAbsolutePosition = (type, index, assoc = 0) => new AbsolutePosition(type, index, assoc)
 
 /**
  * @param {AbstractType<any>} type
  * @param {ID|null} item
+ * @param {number} [assoc]
  *
  * @function
  */
-export const createRelativePosition = (type, item) => {
+export const createRelativePosition = (type, item, assoc) => {
   let typeid = null
   let tname = null
   if (type._item === null) {
     tname = findRootTypeKey(type)
   } else {
-    typeid = type._item.id
+    typeid = createID(type._item.id.client, type._item.id.clock)
   }
-  return new RelativePosition(typeid, tname, item)
+  return new RelativePosition(typeid, tname, item, assoc)
 }
 
 /**
@@ -117,23 +155,35 @@ export const createRelativePosition = (type, item) => {
  *
  * @param {AbstractType<any>} type The base type (e.g. YText or YArray).
  * @param {number} index The absolute position.
+ * @param {number} [assoc]
  * @return {RelativePosition}
  *
  * @function
  */
-export const createRelativePositionFromTypeIndex = (type, index) => {
+export const createRelativePositionFromTypeIndex = (type, index, assoc = 0) => {
   let t = type._start
+  if (assoc < 0) {
+    // associated to the left character or the beginning of a type, increment index if possible.
+    if (index === 0) {
+      return createRelativePosition(type, null, assoc)
+    }
+    index--
+  }
   while (t !== null) {
     if (!t.deleted && t.countable) {
       if (t.length > index) {
         // case 1: found position somewhere in the linked list
-        return createRelativePosition(type, createID(t.id.client, t.id.clock + index))
+        return createRelativePosition(type, createID(t.id.client, t.id.clock + index), assoc)
       }
       index -= t.length
     }
+    if (t.right === null && assoc < 0) {
+      // left-associated position, return last available id
+      return createRelativePosition(type, t.lastId, assoc)
+    }
     t = t.right
   }
-  return createRelativePosition(type, null)
+  return createRelativePosition(type, null, assoc)
 }
 
 /**
@@ -143,7 +193,7 @@ export const createRelativePositionFromTypeIndex = (type, index) => {
  * @function
  */
 export const writeRelativePosition = (encoder, rpos) => {
-  const { type, tname, item } = rpos
+  const { type, tname, item, assoc } = rpos
   if (item !== null) {
     encoding.writeVarUint(encoder, 0)
     writeID(encoder, item)
@@ -158,6 +208,7 @@ export const writeRelativePosition = (encoder, rpos) => {
   } else {
     throw error.unexpectedCase()
   }
+  encoding.writeVarInt(encoder, assoc)
   return encoder
 }
 
@@ -173,7 +224,7 @@ export const encodeRelativePosition = rpos => {
 
 /**
  * @param {decoding.Decoder} decoder
- * @return {RelativePosition|null}
+ * @return {RelativePosition}
  *
  * @function
  */
@@ -195,12 +246,13 @@ export const readRelativePosition = decoder => {
       type = readID(decoder)
     }
   }
-  return new RelativePosition(type, tname, itemID)
+  const assoc = decoding.hasContent(decoder) ? decoding.readVarInt(decoder) : 0
+  return new RelativePosition(type, tname, itemID, assoc)
 }
 
 /**
  * @param {Uint8Array} uint8Array
- * @return {RelativePosition|null}
+ * @return {RelativePosition}
  */
 export const decodeRelativePosition = uint8Array => readRelativePosition(decoding.createDecoder(uint8Array))
 
@@ -216,6 +268,7 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
   const rightID = rpos.item
   const typeID = rpos.type
   const tname = rpos.tname
+  const assoc = rpos.assoc
   let type = null
   let index = 0
   if (rightID !== null) {
@@ -227,9 +280,9 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
     if (!(right instanceof Item)) {
       return null
     }
-    type = right.parent
+    type = /** @type {AbstractType<any>} */ (right.parent)
     if (type._item === null || !type._item.deleted) {
-      index = right.deleted || !right.countable ? 0 : res.diff
+      index = (right.deleted || !right.countable) ? 0 : (res.diff + (assoc >= 0 ? 0 : 1)) // adjust position based on left association if necessary
       let n = right.left
       while (n !== null) {
         if (!n.deleted && n.countable) {
@@ -256,17 +309,22 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
     } else {
       throw error.unexpectedCase()
     }
-    index = type._length
+    if (assoc >= 0) {
+      index = type._length
+    } else {
+      index = 0
+    }
   }
-  return createAbsolutePosition(type, index)
+  return createAbsolutePosition(type, index, rpos.assoc)
 }
 
 /**
  * @param {RelativePosition|null} a
  * @param {RelativePosition|null} b
+ * @return {boolean}
  *
  * @function
  */
 export const compareRelativePositions = (a, b) => a === b || (
-  a !== null && b !== null && a.tname === b.tname && compareIDs(a.item, b.item) && compareIDs(a.type, b.type)
+  a !== null && b !== null && a.tname === b.tname && compareIDs(a.item, b.item) && compareIDs(a.type, b.type) && a.assoc === b.assoc
 )

src/utils/Snapshot.js

@@ -4,21 +4,24 @@ import {
   createDeleteSetFromStructStore,
   getStateVector,
   getItemCleanStart,
-  createID,
   iterateDeletedStructs,
   writeDeleteSet,
   writeStateVector,
   readDeleteSet,
   readStateVector,
   createDeleteSet,
+  createID,
   getState,
-  Transaction, Doc, DeleteSet, Item // eslint-disable-line
+  findIndexSS,
+  UpdateEncoderV2,
+  applyUpdateV2,
+  DSEncoderV1, DSEncoderV2, DSDecoderV1, DSDecoderV2, Transaction, Doc, DeleteSet, Item // eslint-disable-line
 } from '../internals.js'
 
-import * as map from 'lib0/map.js'
-import * as set from 'lib0/set.js'
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
+import * as map from 'lib0/map'
+import * as set from 'lib0/set'
+import * as decoding from 'lib0/decoding'
+import * as encoding from 'lib0/encoding'
 
 export class Snapshot {
   /**
@@ -51,12 +54,12 @@ export const equalSnapshots = (snap1, snap2) => {
   if (sv1.size !== sv2.size || ds1.size !== ds2.size) {
     return false
   }
-  for (const [key, value] of sv1) {
+  for (const [key, value] of sv1.entries()) {
     if (sv2.get(key) !== value) {
       return false
     }
   }
-  for (const [client, dsitems1] of ds1) {
+  for (const [client, dsitems1] of ds1.entries()) {
     const dsitems2 = ds2.get(client) || []
     if (dsitems1.length !== dsitems2.length) {
       return false
@@ -74,23 +77,35 @@ export const equalSnapshots = (snap1, snap2) => {
 
 /**
  * @param {Snapshot} snapshot
+ * @param {DSEncoderV1 | DSEncoderV2} [encoder]
  * @return {Uint8Array}
  */
-export const encodeSnapshot = snapshot => {
-  const encoder = encoding.createEncoder()
+export const encodeSnapshotV2 = (snapshot, encoder = new DSEncoderV2()) => {
   writeDeleteSet(encoder, snapshot.ds)
   writeStateVector(encoder, snapshot.sv)
-  return encoding.toUint8Array(encoder)
+  return encoder.toUint8Array()
+}
+
+/**
+ * @param {Snapshot} snapshot
+ * @return {Uint8Array}
+ */
+export const encodeSnapshot = snapshot => encodeSnapshotV2(snapshot, new DSEncoderV1())
+
+/**
+ * @param {Uint8Array} buf
+ * @param {DSDecoderV1 | DSDecoderV2} [decoder]
+ * @return {Snapshot}
+ */
+export const decodeSnapshotV2 = (buf, decoder = new DSDecoderV2(decoding.createDecoder(buf))) => {
+  return new Snapshot(readDeleteSet(decoder), readStateVector(decoder))
 }
 
 /**
  * @param {Uint8Array} buf
  * @return {Snapshot}
  */
-export const decodeSnapshot = buf => {
-  const decoder = decoding.createDecoder(buf)
-  return new Snapshot(readDeleteSet(decoder), readStateVector(decoder))
-}
+export const decodeSnapshot = buf => decodeSnapshotV2(buf, new DSDecoderV1(decoding.createDecoder(buf)))
 
 /**
  * @param {DeleteSet} ds
@@ -114,9 +129,9 @@ export const snapshot = doc => createSnapshot(createDeleteSetFromStructStore(doc
  * @protected
  * @function
  */
-export const isVisible = (item, snapshot) => snapshot === undefined ? !item.deleted : (
-  snapshot.sv.has(item.id.client) && (snapshot.sv.get(item.id.client) || 0) > item.id.clock && !isDeleted(snapshot.ds, item.id)
-)
+export const isVisible = (item, snapshot) => snapshot === undefined
+  ? !item.deleted
+  : snapshot.sv.has(item.id.client) && (snapshot.sv.get(item.id.client) || 0) > item.id.clock && !isDeleted(snapshot.ds, item.id)
 
 /**
  * @param {Transaction} transaction
@@ -136,3 +151,51 @@ export const splitSnapshotAffectedStructs = (transaction, snapshot) => {
     meta.add(snapshot)
   }
 }
+
+/**
+ * @param {Doc} originDoc
+ * @param {Snapshot} snapshot
+ * @param {Doc} [newDoc] Optionally, you may define the Yjs document that receives the data from originDoc
+ * @return {Doc}
+ */
+export const createDocFromSnapshot = (originDoc, snapshot, newDoc = new Doc()) => {
+  if (originDoc.gc) {
+    // we should not try to restore a GC-ed document, because some of the restored items might have their content deleted
+    throw new Error('originDoc must not be garbage collected')
+  }
+  const { sv, ds } = snapshot
+
+  const encoder = new UpdateEncoderV2()
+  originDoc.transact(transaction => {
+    let size = 0
+    sv.forEach(clock => {
+      if (clock > 0) {
+        size++
+      }
+    })
+    encoding.writeVarUint(encoder.restEncoder, size)
+    // splitting the structs before writing them to the encoder
+    for (const [client, clock] of sv) {
+      if (clock === 0) {
+        continue
+      }
+      if (clock < getState(originDoc.store, client)) {
+        getItemCleanStart(transaction, createID(client, clock))
+      }
+      const structs = originDoc.store.clients.get(client) || []
+      const lastStructIndex = findIndexSS(structs, clock - 1)
+      // write # encoded structs
+      encoding.writeVarUint(encoder.restEncoder, lastStructIndex + 1)
+      encoder.writeClient(client)
+      // first clock written is 0
+      encoding.writeVarUint(encoder.restEncoder, 0)
+      for (let i = 0; i <= lastStructIndex; i++) {
+        structs[i].write(encoder, 0)
+      }
+    }
+    writeDeleteSet(encoder, ds)
+  })
+
+  applyUpdateV2(newDoc, encoder.toUint8Array(), 'snapshot')
+  return newDoc
+}

src/utils/StructStore.js

@@ -2,12 +2,11 @@
 import {
   GC,
   splitItem,
-  GCRef, ItemRef, Transaction, ID, Item // eslint-disable-line
+  Transaction, ID, Item, DSDecoderV2 // eslint-disable-line
 } from '../internals.js'
 
-import * as math from 'lib0/math.js'
-import * as error from 'lib0/error.js'
-import * as decoding from 'lib0/decoding.js' // eslint-disable-line
+import * as math from 'lib0/math'
+import * as error from 'lib0/error'
 
 export class StructStore {
   constructor () {
@@ -16,24 +15,13 @@ export class StructStore {
      */
     this.clients = new Map()
     /**
-     * Store incompleted struct reads here
-     * `i` denotes to the next read operation
-     * We could shift the array of refs instead, but shift is incredible
-     * slow in Chrome for arrays with more than 100k elements
-     * @see tryResumePendingStructRefs
-     * @type {Map<number,{i:number,refs:Array<GCRef|ItemRef>}>}
+     * @type {null | { missing: Map<number, number>, update: Uint8Array }}
      */
-    this.pendingClientsStructRefs = new Map()
+    this.pendingStructs = null
     /**
-     * Stack of pending structs waiting for struct dependencies
-     * Maximum length of stack is structReaders.size
-     * @type {Array<GCRef|ItemRef>}
+     * @type {null | Uint8Array}
      */
-    this.pendingStack = []
-    /**
-     * @type {Array<decoding.Decoder>}
-     */
-    this.pendingDeleteReaders = []
+    this.pendingDs = null
   }
 }
 
@@ -114,7 +102,7 @@ export const addStruct = (store, struct) => {
 
 /**
  * Perform a binary search on a sorted array
- * @param {Array<any>} structs
+ * @param {Array<Item|GC>} structs
  * @param {number} clock
  * @return {number}
  *
@@ -124,10 +112,18 @@ export const addStruct = (store, struct) => {
 export const findIndexSS = (structs, clock) => {
   let left = 0
   let right = structs.length - 1
+  let mid = structs[right]
+  let midclock = mid.id.clock
+  if (midclock === clock) {
+    return right
+  }
+  // @todo does it even make sense to pivot the search?
+  // If a good split misses, it might actually increase the time to find the correct item.
+  // Currently, the only advantage is that search with pivoting might find the item on the first try.
+  let midindex = math.floor((clock / (midclock + mid.length - 1)) * right) // pivoting the search
   while (left <= right) {
-    const midindex = math.floor((left + right) / 2)
-    const mid = structs[midindex]
-    const midclock = mid.id.clock
+    mid = structs[midindex]
+    midclock = mid.id.clock
     if (midclock <= clock) {
       if (clock < midclock + mid.length) {
         return midindex
@@ -136,6 +132,7 @@ export const findIndexSS = (structs, clock) => {
     } else {
       right = midindex - 1
     }
+    midindex = math.floor((left + right) / 2)
   }
   // Always check state before looking for a struct in StructStore
   // Therefore the case of not finding a struct is unexpected
@@ -163,16 +160,10 @@ export const find = (store, id) => {
 
 /**
  * Expects that id is actually in store. This function throws or is an infinite loop otherwise.
- *
- * @param {StructStore} store
- * @param {ID} id
- * @return {Item}
- *
  * @private
  * @function
  */
-// @ts-ignore
-export const getItem = (store, id) => find(store, id)
+export const getItem = /** @type {function(StructStore,ID):Item} */ (find)
 
 /**
  * @param {Transaction} transaction

src/utils/Transaction.js

@@ -1,7 +1,6 @@
 
 import {
   getState,
-  createID,
   writeStructsFromTransaction,
   writeDeleteSet,
   DeleteSet,
@@ -11,15 +10,15 @@ import {
   callEventHandlerListeners,
   Item,
   generateNewClientId,
-  StructStore, ID, AbstractType, AbstractStruct, YEvent, Doc // eslint-disable-line
+  createID,
+  UpdateEncoderV1, UpdateEncoderV2, GC, StructStore, AbstractType, AbstractStruct, YEvent, Doc // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as map from 'lib0/map.js'
-import * as math from 'lib0/math.js'
-import * as set from 'lib0/set.js'
-import * as logging from 'lib0/logging.js'
-import { callAll } from 'lib0/function.js'
+import * as map from 'lib0/map'
+import * as math from 'lib0/math'
+import * as set from 'lib0/set'
+import * as logging from 'lib0/logging'
+import { callAll } from 'lib0/function'
 
 /**
  * A transaction is created for every change on the Yjs model. It is possible
@@ -76,19 +75,19 @@ export class Transaction {
      * All types that were directly modified (property added or child
      * inserted/deleted). New types are not included in this Set.
      * Maps from type to parentSubs (`item.parentSub = null` for YArray)
-     * @type {Map<AbstractType<YEvent>,Set<String|null>>}
+     * @type {Map<AbstractType<YEvent<any>>,Set<String|null>>}
      */
     this.changed = new Map()
     /**
      * Stores the events for the types that observe also child elements.
      * It is mainly used by `observeDeep`.
-     * @type {Map<AbstractType<YEvent>,Array<YEvent>>}
+     * @type {Map<AbstractType<YEvent<any>>,Array<YEvent<any>>>}
      */
     this.changedParentTypes = new Map()
     /**
-     * @type {Set<ID>}
+     * @type {Array<AbstractStruct>}
      */
-    this._mergeStructs = new Set()
+    this._mergeStructs = []
     /**
      * @type {any}
      */
@@ -103,21 +102,34 @@ export class Transaction {
      * @type {boolean}
      */
     this.local = local
+    /**
+     * @type {Set<Doc>}
+     */
+    this.subdocsAdded = new Set()
+    /**
+     * @type {Set<Doc>}
+     */
+    this.subdocsRemoved = new Set()
+    /**
+     * @type {Set<Doc>}
+     */
+    this.subdocsLoaded = new Set()
   }
 }
 
 /**
+ * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
  * @param {Transaction} transaction
+ * @return {boolean} Whether data was written.
  */
-export const computeUpdateMessageFromTransaction = transaction => {
+export const writeUpdateMessageFromTransaction = (encoder, transaction) => {
   if (transaction.deleteSet.clients.size === 0 && !map.any(transaction.afterState, (clock, client) => transaction.beforeState.get(client) !== clock)) {
-    return null
+    return false
   }
-  const encoder = encoding.createEncoder()
   sortAndMergeDeleteSet(transaction.deleteSet)
   writeStructsFromTransaction(encoder, transaction)
   writeDeleteSet(encoder, transaction.deleteSet)
-  return encoder
+  return true
 }
 
 /**
@@ -136,7 +148,7 @@ export const nextID = transaction => {
  * did not change, it was just added and we should not fire events for `type`.
  *
  * @param {Transaction} transaction
- * @param {AbstractType<YEvent>} type
+ * @param {AbstractType<YEvent<any>>} type
  * @param {string|null} parentSub
  */
 export const addChangedTypeToTransaction = (transaction, type, parentSub) => {
@@ -156,8 +168,8 @@ const tryToMergeWithLeft = (structs, pos) => {
   if (left.deleted === right.deleted && left.constructor === right.constructor) {
     if (left.mergeWith(right)) {
       structs.splice(pos, 1)
-      if (right instanceof Item && right.parentSub !== null && right.parent._map.get(right.parentSub) === right) {
-        right.parent._map.set(right.parentSub, /** @type {Item} */ (left))
+      if (right instanceof Item && right.parentSub !== null && /** @type {AbstractType<any>} */ (right.parent)._map.get(right.parentSub) === right) {
+        /** @type {AbstractType<any>} */ (right.parent)._map.set(right.parentSub, /** @type {Item} */ (left))
       }
     }
   }
@@ -169,8 +181,8 @@ const tryToMergeWithLeft = (structs, pos) => {
  * @param {function(Item):boolean} gcFilter
  */
 const tryGcDeleteSet = (ds, store, gcFilter) => {
-  for (const [client, deleteItems] of ds.clients) {
-    const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
+  for (const [client, deleteItems] of ds.clients.entries()) {
+    const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
     for (let di = deleteItems.length - 1; di >= 0; di--) {
       const deleteItem = deleteItems[di]
       const endDeleteItemClock = deleteItem.clock + deleteItem.len
@@ -198,8 +210,8 @@ const tryGcDeleteSet = (ds, store, gcFilter) => {
 const tryMergeDeleteSet = (ds, store) => {
   // try to merge deleted / gc'd items
   // merge from right to left for better efficiecy and so we don't miss any merge targets
-  for (const [client, deleteItems] of ds.clients) {
-    const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
+  ds.clients.forEach((deleteItems, client) => {
+    const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
     for (let di = deleteItems.length - 1; di >= 0; di--) {
       const deleteItem = deleteItems[di]
       // start with merging the item next to the last deleted item
@@ -212,7 +224,7 @@ const tryMergeDeleteSet = (ds, store) => {
         tryToMergeWithLeft(structs, si)
       }
     }
-  }
+  })
 }
 
 /**
@@ -235,10 +247,10 @@ const cleanupTransactions = (transactionCleanups, i) => {
     const doc = transaction.doc
     const store = doc.store
     const ds = transaction.deleteSet
+    const mergeStructs = transaction._mergeStructs
     try {
       sortAndMergeDeleteSet(ds)
       transaction.afterState = getStateVector(transaction.doc.store)
-      doc._transaction = null
       doc.emit('beforeObserverCalls', [transaction, doc])
       /**
        * An array of event callbacks.
@@ -271,6 +283,9 @@ const cleanupTransactions = (transactionCleanups, i) => {
                 .forEach(event => {
                   event.currentTarget = type
                 })
+              // sort events by path length so that top-level events are fired first.
+              events
+                .sort((event1, event2) => event1.path.length - event2.path.length)
               // We don't need to check for events.length
               // because we know it has at least one element
               callEventHandlerListeners(type._dEH, events, transaction)
@@ -289,24 +304,23 @@ const cleanupTransactions = (transactionCleanups, i) => {
       tryMergeDeleteSet(ds, store)
 
       // on all affected store.clients props, try to merge
-      for (const [client, clock] of transaction.afterState) {
+      transaction.afterState.forEach((clock, client) => {
         const beforeClock = transaction.beforeState.get(client) || 0
         if (beforeClock !== clock) {
-          const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
+          const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
           // we iterate from right to left so we can safely remove entries
           const firstChangePos = math.max(findIndexSS(structs, beforeClock), 1)
           for (let i = structs.length - 1; i >= firstChangePos; i--) {
             tryToMergeWithLeft(structs, i)
           }
         }
-      }
+      })
       // try to merge mergeStructs
       // @todo: it makes more sense to transform mergeStructs to a DS, sort it, and merge from right to left
       //        but at the moment DS does not handle duplicates
-      for (const mid of transaction._mergeStructs) {
-        const client = mid.client
-        const clock = mid.clock
-        const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
+      for (let i = 0; i < mergeStructs.length; i++) {
+        const { client, clock } = mergeStructs[i].id
+        const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
         const replacedStructPos = findIndexSS(structs, clock)
         if (replacedStructPos + 1 < structs.length) {
           tryToMergeWithLeft(structs, replacedStructPos + 1)
@@ -316,19 +330,42 @@ const cleanupTransactions = (transactionCleanups, i) => {
         }
       }
       if (!transaction.local && transaction.afterState.get(doc.clientID) !== transaction.beforeState.get(doc.clientID)) {
-        doc.clientID = generateNewClientId()
         logging.print(logging.ORANGE, logging.BOLD, '[yjs] ', logging.UNBOLD, logging.RED, 'Changed the client-id because another client seems to be using it.')
+        doc.clientID = generateNewClientId()
       }
       // @todo Merge all the transactions into one and provide send the data as a single update message
       doc.emit('afterTransactionCleanup', [transaction, doc])
       if (doc._observers.has('update')) {
-        const updateMessage = computeUpdateMessageFromTransaction(transaction)
-        if (updateMessage !== null) {
-          doc.emit('update', [encoding.toUint8Array(updateMessage), transaction.origin, doc])
+        const encoder = new UpdateEncoderV1()
+        const hasContent = writeUpdateMessageFromTransaction(encoder, transaction)
+        if (hasContent) {
+          doc.emit('update', [encoder.toUint8Array(), transaction.origin, doc, transaction])
         }
       }
+      if (doc._observers.has('updateV2')) {
+        const encoder = new UpdateEncoderV2()
+        const hasContent = writeUpdateMessageFromTransaction(encoder, transaction)
+        if (hasContent) {
+          doc.emit('updateV2', [encoder.toUint8Array(), transaction.origin, doc, transaction])
+        }
+      }
+      const { subdocsAdded, subdocsLoaded, subdocsRemoved } = transaction
+      if (subdocsAdded.size > 0 || subdocsRemoved.size > 0 || subdocsLoaded.size > 0) {
+        subdocsAdded.forEach(subdoc => {
+          subdoc.clientID = doc.clientID
+          if (subdoc.collectionid == null) {
+            subdoc.collectionid = doc.collectionid
+          }
+          doc.subdocs.add(subdoc)
+        })
+        subdocsRemoved.forEach(subdoc => doc.subdocs.delete(subdoc))
+        doc.emit('subdocs', [{ loaded: subdocsLoaded, added: subdocsAdded, removed: subdocsRemoved }, doc, transaction])
+        subdocsRemoved.forEach(subdoc => subdoc.destroy())
+      }
+
       if (transactionCleanups.length <= i + 1) {
         doc._transactionCleanups = []
+        doc.emit('afterAllTransactions', [doc, transactionCleanups])
       } else {
         cleanupTransactions(transactionCleanups, i + 1)
       }
@@ -352,21 +389,28 @@ export const transact = (doc, f, origin = null, local = true) => {
     initialCall = true
     doc._transaction = new Transaction(doc, origin, local)
     transactionCleanups.push(doc._transaction)
+    if (transactionCleanups.length === 1) {
+      doc.emit('beforeAllTransactions', [doc])
+    }
     doc.emit('beforeTransaction', [doc._transaction, doc])
   }
   try {
     f(doc._transaction)
   } finally {
-    if (initialCall && transactionCleanups[0] === doc._transaction) {
-      // The first transaction ended, now process observer calls.
-      // Observer call may create new transactions for which we need to call the observers and do cleanup.
-      // We don't want to nest these calls, so we execute these calls one after
-      // another.
-      // Also we need to ensure that all cleanups are called, even if the
-      // observes throw errors.
-      // This file is full of hacky try {} finally {} blocks to ensure that an
-      // event can throw errors and also that the cleanup is called.
-      cleanupTransactions(transactionCleanups, 0)
+    if (initialCall) {
+      const finishCleanup = doc._transaction === transactionCleanups[0]
+      doc._transaction = null
+      if (finishCleanup) {
+        // The first transaction ended, now process observer calls.
+        // Observer call may create new transactions for which we need to call the observers and do cleanup.
+        // We don't want to nest these calls, so we execute these calls one after
+        // another.
+        // Also we need to ensure that all cleanups are called, even if the
+        // observes throw errors.
+        // This file is full of hacky try {} finally {} blocks to ensure that an
+        // event can throw errors and also that the cleanup is called.
+        cleanupTransactions(transactionCleanups, 0)
+      }
     }
   }
 }

src/utils/UndoManager.js

@@ -3,35 +3,46 @@ import {
   iterateDeletedStructs,
   keepItem,
   transact,
-  redoItem,
-  iterateStructs,
-  isParentOf,
   createID,
+  redoItem,
+  isParentOf,
   followRedone,
   getItemCleanStart,
-  getState,
-  Transaction, Doc, Item, GC, DeleteSet, AbstractType // eslint-disable-line
+  isDeleted,
+  addToDeleteSet,
+  Transaction, Doc, Item, GC, DeleteSet, AbstractType, YEvent // eslint-disable-line
 } from '../internals.js'
 
-import * as time from 'lib0/time.js'
-import { Observable } from 'lib0/observable.js'
+import * as time from 'lib0/time'
+import * as array from 'lib0/array'
+import { Observable } from 'lib0/observable'
 
 class StackItem {
   /**
-   * @param {DeleteSet} ds
-   * @param {number} start clock start of the local client
-   * @param {number} len
+   * @param {DeleteSet} deletions
+   * @param {DeleteSet} insertions
    */
-  constructor (ds, start, len) {
-    this.ds = ds
-    this.start = start
-    this.len = len
+  constructor (deletions, insertions) {
+    this.insertions = insertions
+    this.deletions = deletions
     /**
      * Use this to save and restore metadata like selection range
      */
     this.meta = new Map()
   }
 }
+/**
+ * @param {Transaction} tr
+ * @param {UndoManager} um
+ * @param {StackItem} stackItem
+ */
+const clearUndoManagerStackItem = (tr, um, stackItem) => {
+  iterateDeletedStructs(tr, stackItem.deletions, item => {
+    if (item instanceof Item && um.scope.some(type => isParentOf(type, item))) {
+      keepItem(item, false)
+    }
+  })
+}
 
 /**
  * @param {UndoManager} undoManager
@@ -45,53 +56,33 @@ const popStackItem = (undoManager, stack, eventType) => {
    * @type {StackItem?}
    */
   let result = null
+  /**
+   * Keep a reference to the transaction so we can fire the event with the changedParentTypes
+   * @type {any}
+   */
+  let _tr = null
   const doc = undoManager.doc
   const scope = undoManager.scope
   transact(doc, transaction => {
     while (stack.length > 0 && result === null) {
       const store = doc.store
-      const clientID = doc.clientID
       const stackItem = /** @type {StackItem} */ (stack.pop())
-      const stackStartClock = stackItem.start
-      const stackEndClock = stackItem.start + stackItem.len
+      /**
+       * @type {Set<Item>}
+       */
       const itemsToRedo = new Set()
-      // @todo iterateStructs should not need the structs parameter
-      const structs = /** @type {Array<GC|Item>} */ (store.clients.get(clientID))
-      let performedChange = false
-      if (stackStartClock !== stackEndClock) {
-        // make sure structs don't overlap with the range of created operations [stackItem.start, stackItem.start + stackItem.end)
-        getItemCleanStart(transaction, createID(clientID, stackStartClock))
-        if (stackEndClock < getState(doc.store, clientID)) {
-          getItemCleanStart(transaction, createID(clientID, stackEndClock))
-        }
-      }
-      iterateDeletedStructs(transaction, stackItem.ds, struct => {
-        if (
-          struct instanceof Item &&
-          scope.some(type => isParentOf(type, struct)) &&
-          // Never redo structs in [stackItem.start, stackItem.start + stackItem.end) because they were created and deleted in the same capture interval.
-          !(struct.id.client === clientID && struct.id.clock >= stackStartClock && struct.id.clock < stackEndClock)
-        ) {
-          itemsToRedo.add(struct)
-        }
-      })
-      itemsToRedo.forEach(struct => {
-        performedChange = redoItem(transaction, struct, itemsToRedo) !== null || performedChange
-      })
       /**
        * @type {Array<Item>}
        */
       const itemsToDelete = []
-      iterateStructs(transaction, structs, stackStartClock, stackItem.len, struct => {
+      let performedChange = false
+      iterateDeletedStructs(transaction, stackItem.insertions, struct => {
         if (struct instanceof Item) {
           if (struct.redone !== null) {
             let { item, diff } = followRedone(store, struct.id)
             if (diff > 0) {
               item = getItemCleanStart(transaction, createID(item.id.client, item.id.clock + diff))
             }
-            if (item.length > stackItem.len) {
-              getItemCleanStart(transaction, createID(item.id.client, stackEndClock))
-            }
             struct = item
           }
           if (!struct.deleted && scope.some(type => isParentOf(type, /** @type {Item} */ (struct)))) {
@@ -99,6 +90,19 @@ const popStackItem = (undoManager, stack, eventType) => {
           }
         }
       })
+      iterateDeletedStructs(transaction, stackItem.deletions, struct => {
+        if (
+          struct instanceof Item &&
+          scope.some(type => isParentOf(type, struct)) &&
+          // Never redo structs in stackItem.insertions because they were created and deleted in the same capture interval.
+          !isDeleted(stackItem.insertions, struct.id)
+        ) {
+          itemsToRedo.add(struct)
+        }
+      })
+      itemsToRedo.forEach(struct => {
+        performedChange = redoItem(transaction, struct, itemsToRedo, stackItem.insertions, undoManager.ignoreRemoteMapChanges) !== null || performedChange
+      })
       // We want to delete in reverse order so that children are deleted before
       // parents, so we have more information available when items are filtered.
       for (let i = itemsToDelete.length - 1; i >= 0; i--) {
@@ -108,23 +112,34 @@ const popStackItem = (undoManager, stack, eventType) => {
           performedChange = true
         }
       }
-      result = stackItem
-      if (result != null) {
-        undoManager.emit('stack-item-popped', [{ stackItem: result, type: eventType }, undoManager])
-      }
+      result = performedChange ? stackItem : null
     }
+    transaction.changed.forEach((subProps, type) => {
+      // destroy search marker if necessary
+      if (subProps.has(null) && type._searchMarker) {
+        type._searchMarker.length = 0
+      }
+    })
+    _tr = transaction
   }, undoManager)
+  if (result != null) {
+    const changedParentTypes = _tr.changedParentTypes
+    undoManager.emit('stack-item-popped', [{ stackItem: result, type: eventType, changedParentTypes }, undoManager])
+  }
   return result
 }
 
 /**
  * @typedef {Object} UndoManagerOptions
  * @property {number} [UndoManagerOptions.captureTimeout=500]
+ * @property {function(Transaction):boolean} [UndoManagerOptions.captureTransaction] Do not capture changes of a Transaction if result false.
  * @property {function(Item):boolean} [UndoManagerOptions.deleteFilter=()=>true] Sometimes
- * it is necessary to filter whan an Undo/Redo operation can delete. If this
+ * it is necessary to filter what an Undo/Redo operation can delete. If this
  * filter returns false, the type/item won't be deleted even it is in the
  * undo/redo scope.
  * @property {Set<any>} [UndoManagerOptions.trackedOrigins=new Set([null])]
+ * @property {boolean} [ignoreRemoteMapChanges] Experimental. By default, the UndoManager will never overwrite remote changes. Enable this property to enable overwriting remote changes on key-value changes (Y.Map, properties on Y.Xml, etc..).
+ * @property {Doc} [doc] The document that this UndoManager operates on. Only needed if typeScope is empty.
  */
 
 /**
@@ -134,22 +149,31 @@ const popStackItem = (undoManager, stack, eventType) => {
  * Fires 'stack-item-popped' event when a stack item was popped from either the
  * undo- or the redo-stack. You may restore the saved stack information from `event.stackItem.meta`.
  *
- * @extends {Observable<'stack-item-added'|'stack-item-popped'>}
+ * @extends {Observable<'stack-item-added'|'stack-item-popped'|'stack-cleared'|'stack-item-updated'>}
  */
 export class UndoManager extends Observable {
   /**
    * @param {AbstractType<any>|Array<AbstractType<any>>} typeScope Accepts either a single type, or an array of types
    * @param {UndoManagerOptions} options
    */
-  constructor (typeScope, { captureTimeout, deleteFilter = () => true, trackedOrigins = new Set([null]) } = {}) {
-    if (captureTimeout == null) {
-      captureTimeout = 500
-    }
+  constructor (typeScope, {
+    captureTimeout = 500,
+    captureTransaction = tr => true,
+    deleteFilter = () => true,
+    trackedOrigins = new Set([null]),
+    ignoreRemoteMapChanges = false,
+    doc = /** @type {Doc} */ (array.isArray(typeScope) ? typeScope[0].doc : typeScope.doc)
+  } = {}) {
     super()
-    this.scope = typeScope instanceof Array ? typeScope : [typeScope]
+    /**
+     * @type {Array<AbstractType<any>>}
+     */
+    this.scope = []
+    this.addToScope(typeScope)
     this.deleteFilter = deleteFilter
     trackedOrigins.add(this)
     this.trackedOrigins = trackedOrigins
+    this.captureTransaction = captureTransaction
     /**
      * @type {Array<StackItem>}
      */
@@ -165,11 +189,20 @@ export class UndoManager extends Observable {
      */
     this.undoing = false
     this.redoing = false
-    this.doc = /** @type {Doc} */ (this.scope[0].doc)
+    this.doc = doc
     this.lastChange = 0
-    this.doc.on('afterTransaction', /** @param {Transaction} transaction */ transaction => {
+    this.ignoreRemoteMapChanges = ignoreRemoteMapChanges
+    this.captureTimeout = captureTimeout
+    /**
+     * @param {Transaction} transaction
+     */
+    this.afterTransactionHandler = transaction => {
       // Only track certain transactions
-      if (!this.scope.some(type => transaction.changedParentTypes.has(type)) || (!this.trackedOrigins.has(transaction.origin) && (!transaction.origin || !this.trackedOrigins.has(transaction.origin.constructor)))) {
+      if (
+        !this.captureTransaction(transaction) ||
+        !this.scope.some(type => transaction.changedParentTypes.has(type)) ||
+        (!this.trackedOrigins.has(transaction.origin) && (!transaction.origin || !this.trackedOrigins.has(transaction.origin.constructor)))
+      ) {
         return
       }
       const undoing = this.undoing
@@ -179,19 +212,27 @@ export class UndoManager extends Observable {
         this.stopCapturing() // next undo should not be appended to last stack item
       } else if (!redoing) {
         // neither undoing nor redoing: delete redoStack
-        this.redoStack = []
+        this.clear(false, true)
       }
-      const beforeState = transaction.beforeState.get(this.doc.clientID) || 0
-      const afterState = transaction.afterState.get(this.doc.clientID) || 0
+      const insertions = new DeleteSet()
+      transaction.afterState.forEach((endClock, client) => {
+        const startClock = transaction.beforeState.get(client) || 0
+        const len = endClock - startClock
+        if (len > 0) {
+          addToDeleteSet(insertions, client, startClock, len)
+        }
+      })
       const now = time.getUnixTime()
-      if (now - this.lastChange < captureTimeout && stack.length > 0 && !undoing && !redoing) {
+      let didAdd = false
+      if (this.lastChange > 0 && now - this.lastChange < this.captureTimeout && stack.length > 0 && !undoing && !redoing) {
         // append change to last stack op
         const lastOp = stack[stack.length - 1]
-        lastOp.ds = mergeDeleteSets([lastOp.ds, transaction.deleteSet])
-        lastOp.len = afterState - lastOp.start
+        lastOp.deletions = mergeDeleteSets([lastOp.deletions, transaction.deleteSet])
+        lastOp.insertions = mergeDeleteSets([lastOp.insertions, insertions])
       } else {
         // create a new stack op
-        stack.push(new StackItem(transaction.deleteSet, beforeState, afterState - beforeState))
+        stack.push(new StackItem(transaction.deleteSet, insertions))
+        didAdd = true
       }
       if (!undoing && !redoing) {
         this.lastChange = now
@@ -202,27 +243,59 @@ export class UndoManager extends Observable {
           keepItem(item, true)
         }
       })
-      this.emit('stack-item-added', [{ stackItem: stack[stack.length - 1], origin: transaction.origin, type: undoing ? 'redo' : 'undo' }, this])
+      const changeEvent = [{ stackItem: stack[stack.length - 1], origin: transaction.origin, type: undoing ? 'redo' : 'undo', changedParentTypes: transaction.changedParentTypes }, this]
+      if (didAdd) {
+        this.emit('stack-item-added', changeEvent)
+      } else {
+        this.emit('stack-item-updated', changeEvent)
+      }
+    }
+    this.doc.on('afterTransaction', this.afterTransactionHandler)
+    this.doc.on('destroy', () => {
+      this.destroy()
     })
   }
 
-  clear () {
-    this.doc.transact(transaction => {
-      /**
-       * @param {StackItem} stackItem
-       */
-      const clearItem = stackItem => {
-        iterateDeletedStructs(transaction, stackItem.ds, item => {
-          if (item instanceof Item && this.scope.some(type => isParentOf(type, item))) {
-            keepItem(item, false)
-          }
-        })
+  /**
+   * @param {Array<AbstractType<any>> | AbstractType<any>} ytypes
+   */
+  addToScope (ytypes) {
+    ytypes = array.isArray(ytypes) ? ytypes : [ytypes]
+    ytypes.forEach(ytype => {
+      if (this.scope.every(yt => yt !== ytype)) {
+        this.scope.push(ytype)
       }
-      this.undoStack.forEach(clearItem)
-      this.redoStack.forEach(clearItem)
     })
-    this.undoStack = []
-    this.redoStack = []
+  }
+
+  /**
+   * @param {any} origin
+   */
+  addTrackedOrigin (origin) {
+    this.trackedOrigins.add(origin)
+  }
+
+  /**
+   * @param {any} origin
+   */
+  removeTrackedOrigin (origin) {
+    this.trackedOrigins.delete(origin)
+  }
+
+  clear (clearUndoStack = true, clearRedoStack = true) {
+    if ((clearUndoStack && this.canUndo()) || (clearRedoStack && this.canRedo())) {
+      this.doc.transact(tr => {
+        if (clearUndoStack) {
+          this.undoStack.forEach(item => clearUndoManagerStackItem(tr, this, item))
+          this.undoStack = []
+        }
+        if (clearRedoStack) {
+          this.redoStack.forEach(item => clearUndoManagerStackItem(tr, this, item))
+          this.redoStack = []
+        }
+        this.emit('stack-cleared', [{ undoStackCleared: clearUndoStack, redoStackCleared: clearRedoStack }])
+      })
+    }
   }
 
   /**
@@ -280,4 +353,28 @@ export class UndoManager extends Observable {
     }
     return res
   }
+
+  /**
+   * Are undo steps available?
+   *
+   * @return {boolean} `true` if undo is possible
+   */
+  canUndo () {
+    return this.undoStack.length > 0
+  }
+
+  /**
+   * Are redo steps available?
+   *
+   * @return {boolean} `true` if redo is possible
+   */
+  canRedo () {
+    return this.redoStack.length > 0
+  }
+
+  destroy () {
+    this.trackedOrigins.delete(this)
+    this.doc.off('afterTransaction', this.afterTransactionHandler)
+    super.destroy()
+  }
 }

src/utils/UpdateDecoder.js

@@ -0,0 +1,281 @@
+import * as buffer from 'lib0/buffer'
+import * as decoding from 'lib0/decoding'
+import {
+  ID, createID
+} from '../internals.js'
+
+export class DSDecoderV1 {
+  /**
+   * @param {decoding.Decoder} decoder
+   */
+  constructor (decoder) {
+    this.restDecoder = decoder
+  }
+
+  resetDsCurVal () {
+    // nop
+  }
+
+  /**
+   * @return {number}
+   */
+  readDsClock () {
+    return decoding.readVarUint(this.restDecoder)
+  }
+
+  /**
+   * @return {number}
+   */
+  readDsLen () {
+    return decoding.readVarUint(this.restDecoder)
+  }
+}
+
+export class UpdateDecoderV1 extends DSDecoderV1 {
+  /**
+   * @return {ID}
+   */
+  readLeftID () {
+    return createID(decoding.readVarUint(this.restDecoder), decoding.readVarUint(this.restDecoder))
+  }
+
+  /**
+   * @return {ID}
+   */
+  readRightID () {
+    return createID(decoding.readVarUint(this.restDecoder), decoding.readVarUint(this.restDecoder))
+  }
+
+  /**
+   * Read the next client id.
+   * Use this in favor of readID whenever possible to reduce the number of objects created.
+   */
+  readClient () {
+    return decoding.readVarUint(this.restDecoder)
+  }
+
+  /**
+   * @return {number} info An unsigned 8-bit integer
+   */
+  readInfo () {
+    return decoding.readUint8(this.restDecoder)
+  }
+
+  /**
+   * @return {string}
+   */
+  readString () {
+    return decoding.readVarString(this.restDecoder)
+  }
+
+  /**
+   * @return {boolean} isKey
+   */
+  readParentInfo () {
+    return decoding.readVarUint(this.restDecoder) === 1
+  }
+
+  /**
+   * @return {number} info An unsigned 8-bit integer
+   */
+  readTypeRef () {
+    return decoding.readVarUint(this.restDecoder)
+  }
+
+  /**
+   * Write len of a struct - well suited for Opt RLE encoder.
+   *
+   * @return {number} len
+   */
+  readLen () {
+    return decoding.readVarUint(this.restDecoder)
+  }
+
+  /**
+   * @return {any}
+   */
+  readAny () {
+    return decoding.readAny(this.restDecoder)
+  }
+
+  /**
+   * @return {Uint8Array}
+   */
+  readBuf () {
+    return buffer.copyUint8Array(decoding.readVarUint8Array(this.restDecoder))
+  }
+
+  /**
+   * Legacy implementation uses JSON parse. We use any-decoding in v2.
+   *
+   * @return {any}
+   */
+  readJSON () {
+    return JSON.parse(decoding.readVarString(this.restDecoder))
+  }
+
+  /**
+   * @return {string}
+   */
+  readKey () {
+    return decoding.readVarString(this.restDecoder)
+  }
+}
+
+export class DSDecoderV2 {
+  /**
+   * @param {decoding.Decoder} decoder
+   */
+  constructor (decoder) {
+    /**
+     * @private
+     */
+    this.dsCurrVal = 0
+    this.restDecoder = decoder
+  }
+
+  resetDsCurVal () {
+    this.dsCurrVal = 0
+  }
+
+  /**
+   * @return {number}
+   */
+  readDsClock () {
+    this.dsCurrVal += decoding.readVarUint(this.restDecoder)
+    return this.dsCurrVal
+  }
+
+  /**
+   * @return {number}
+   */
+  readDsLen () {
+    const diff = decoding.readVarUint(this.restDecoder) + 1
+    this.dsCurrVal += diff
+    return diff
+  }
+}
+
+export class UpdateDecoderV2 extends DSDecoderV2 {
+  /**
+   * @param {decoding.Decoder} decoder
+   */
+  constructor (decoder) {
+    super(decoder)
+    /**
+     * List of cached keys. If the keys[id] does not exist, we read a new key
+     * from stringEncoder and push it to keys.
+     *
+     * @type {Array<string>}
+     */
+    this.keys = []
+    decoding.readVarUint(decoder) // read feature flag - currently unused
+    this.keyClockDecoder = new decoding.IntDiffOptRleDecoder(decoding.readVarUint8Array(decoder))
+    this.clientDecoder = new decoding.UintOptRleDecoder(decoding.readVarUint8Array(decoder))
+    this.leftClockDecoder = new decoding.IntDiffOptRleDecoder(decoding.readVarUint8Array(decoder))
+    this.rightClockDecoder = new decoding.IntDiffOptRleDecoder(decoding.readVarUint8Array(decoder))
+    this.infoDecoder = new decoding.RleDecoder(decoding.readVarUint8Array(decoder), decoding.readUint8)
+    this.stringDecoder = new decoding.StringDecoder(decoding.readVarUint8Array(decoder))
+    this.parentInfoDecoder = new decoding.RleDecoder(decoding.readVarUint8Array(decoder), decoding.readUint8)
+    this.typeRefDecoder = new decoding.UintOptRleDecoder(decoding.readVarUint8Array(decoder))
+    this.lenDecoder = new decoding.UintOptRleDecoder(decoding.readVarUint8Array(decoder))
+  }
+
+  /**
+   * @return {ID}
+   */
+  readLeftID () {
+    return new ID(this.clientDecoder.read(), this.leftClockDecoder.read())
+  }
+
+  /**
+   * @return {ID}
+   */
+  readRightID () {
+    return new ID(this.clientDecoder.read(), this.rightClockDecoder.read())
+  }
+
+  /**
+   * Read the next client id.
+   * Use this in favor of readID whenever possible to reduce the number of objects created.
+   */
+  readClient () {
+    return this.clientDecoder.read()
+  }
+
+  /**
+   * @return {number} info An unsigned 8-bit integer
+   */
+  readInfo () {
+    return /** @type {number} */ (this.infoDecoder.read())
+  }
+
+  /**
+   * @return {string}
+   */
+  readString () {
+    return this.stringDecoder.read()
+  }
+
+  /**
+   * @return {boolean}
+   */
+  readParentInfo () {
+    return this.parentInfoDecoder.read() === 1
+  }
+
+  /**
+   * @return {number} An unsigned 8-bit integer
+   */
+  readTypeRef () {
+    return this.typeRefDecoder.read()
+  }
+
+  /**
+   * Write len of a struct - well suited for Opt RLE encoder.
+   *
+   * @return {number}
+   */
+  readLen () {
+    return this.lenDecoder.read()
+  }
+
+  /**
+   * @return {any}
+   */
+  readAny () {
+    return decoding.readAny(this.restDecoder)
+  }
+
+  /**
+   * @return {Uint8Array}
+   */
+  readBuf () {
+    return decoding.readVarUint8Array(this.restDecoder)
+  }
+
+  /**
+   * This is mainly here for legacy purposes.
+   *
+   * Initial we incoded objects using JSON. Now we use the much faster lib0/any-encoder. This method mainly exists for legacy purposes for the v1 encoder.
+   *
+   * @return {any}
+   */
+  readJSON () {
+    return decoding.readAny(this.restDecoder)
+  }
+
+  /**
+   * @return {string}
+   */
+  readKey () {
+    const keyClock = this.keyClockDecoder.read()
+    if (keyClock < this.keys.length) {
+      return this.keys[keyClock]
+    } else {
+      const key = this.stringDecoder.read()
+      this.keys.push(key)
+      return key
+    }
+  }
+}

src/utils/UpdateEncoder.js

@@ -0,0 +1,321 @@
+
+import * as error from 'lib0/error'
+import * as encoding from 'lib0/encoding'
+
+import {
+  ID // eslint-disable-line
+} from '../internals.js'
+
+export class DSEncoderV1 {
+  constructor () {
+    this.restEncoder = encoding.createEncoder()
+  }
+
+  toUint8Array () {
+    return encoding.toUint8Array(this.restEncoder)
+  }
+
+  resetDsCurVal () {
+    // nop
+  }
+
+  /**
+   * @param {number} clock
+   */
+  writeDsClock (clock) {
+    encoding.writeVarUint(this.restEncoder, clock)
+  }
+
+  /**
+   * @param {number} len
+   */
+  writeDsLen (len) {
+    encoding.writeVarUint(this.restEncoder, len)
+  }
+}
+
+export class UpdateEncoderV1 extends DSEncoderV1 {
+  /**
+   * @param {ID} id
+   */
+  writeLeftID (id) {
+    encoding.writeVarUint(this.restEncoder, id.client)
+    encoding.writeVarUint(this.restEncoder, id.clock)
+  }
+
+  /**
+   * @param {ID} id
+   */
+  writeRightID (id) {
+    encoding.writeVarUint(this.restEncoder, id.client)
+    encoding.writeVarUint(this.restEncoder, id.clock)
+  }
+
+  /**
+   * Use writeClient and writeClock instead of writeID if possible.
+   * @param {number} client
+   */
+  writeClient (client) {
+    encoding.writeVarUint(this.restEncoder, client)
+  }
+
+  /**
+   * @param {number} info An unsigned 8-bit integer
+   */
+  writeInfo (info) {
+    encoding.writeUint8(this.restEncoder, info)
+  }
+
+  /**
+   * @param {string} s
+   */
+  writeString (s) {
+    encoding.writeVarString(this.restEncoder, s)
+  }
+
+  /**
+   * @param {boolean} isYKey
+   */
+  writeParentInfo (isYKey) {
+    encoding.writeVarUint(this.restEncoder, isYKey ? 1 : 0)
+  }
+
+  /**
+   * @param {number} info An unsigned 8-bit integer
+   */
+  writeTypeRef (info) {
+    encoding.writeVarUint(this.restEncoder, info)
+  }
+
+  /**
+   * Write len of a struct - well suited for Opt RLE encoder.
+   *
+   * @param {number} len
+   */
+  writeLen (len) {
+    encoding.writeVarUint(this.restEncoder, len)
+  }
+
+  /**
+   * @param {any} any
+   */
+  writeAny (any) {
+    encoding.writeAny(this.restEncoder, any)
+  }
+
+  /**
+   * @param {Uint8Array} buf
+   */
+  writeBuf (buf) {
+    encoding.writeVarUint8Array(this.restEncoder, buf)
+  }
+
+  /**
+   * @param {any} embed
+   */
+  writeJSON (embed) {
+    encoding.writeVarString(this.restEncoder, JSON.stringify(embed))
+  }
+
+  /**
+   * @param {string} key
+   */
+  writeKey (key) {
+    encoding.writeVarString(this.restEncoder, key)
+  }
+}
+
+export class DSEncoderV2 {
+  constructor () {
+    this.restEncoder = encoding.createEncoder() // encodes all the rest / non-optimized
+    this.dsCurrVal = 0
+  }
+
+  toUint8Array () {
+    return encoding.toUint8Array(this.restEncoder)
+  }
+
+  resetDsCurVal () {
+    this.dsCurrVal = 0
+  }
+
+  /**
+   * @param {number} clock
+   */
+  writeDsClock (clock) {
+    const diff = clock - this.dsCurrVal
+    this.dsCurrVal = clock
+    encoding.writeVarUint(this.restEncoder, diff)
+  }
+
+  /**
+   * @param {number} len
+   */
+  writeDsLen (len) {
+    if (len === 0) {
+      error.unexpectedCase()
+    }
+    encoding.writeVarUint(this.restEncoder, len - 1)
+    this.dsCurrVal += len
+  }
+}
+
+export class UpdateEncoderV2 extends DSEncoderV2 {
+  constructor () {
+    super()
+    /**
+     * @type {Map<string,number>}
+     */
+    this.keyMap = new Map()
+    /**
+     * Refers to the next uniqe key-identifier to me used.
+     * See writeKey method for more information.
+     *
+     * @type {number}
+     */
+    this.keyClock = 0
+    this.keyClockEncoder = new encoding.IntDiffOptRleEncoder()
+    this.clientEncoder = new encoding.UintOptRleEncoder()
+    this.leftClockEncoder = new encoding.IntDiffOptRleEncoder()
+    this.rightClockEncoder = new encoding.IntDiffOptRleEncoder()
+    this.infoEncoder = new encoding.RleEncoder(encoding.writeUint8)
+    this.stringEncoder = new encoding.StringEncoder()
+    this.parentInfoEncoder = new encoding.RleEncoder(encoding.writeUint8)
+    this.typeRefEncoder = new encoding.UintOptRleEncoder()
+    this.lenEncoder = new encoding.UintOptRleEncoder()
+  }
+
+  toUint8Array () {
+    const encoder = encoding.createEncoder()
+    encoding.writeVarUint(encoder, 0) // this is a feature flag that we might use in the future
+    encoding.writeVarUint8Array(encoder, this.keyClockEncoder.toUint8Array())
+    encoding.writeVarUint8Array(encoder, this.clientEncoder.toUint8Array())
+    encoding.writeVarUint8Array(encoder, this.leftClockEncoder.toUint8Array())
+    encoding.writeVarUint8Array(encoder, this.rightClockEncoder.toUint8Array())
+    encoding.writeVarUint8Array(encoder, encoding.toUint8Array(this.infoEncoder))
+    encoding.writeVarUint8Array(encoder, this.stringEncoder.toUint8Array())
+    encoding.writeVarUint8Array(encoder, encoding.toUint8Array(this.parentInfoEncoder))
+    encoding.writeVarUint8Array(encoder, this.typeRefEncoder.toUint8Array())
+    encoding.writeVarUint8Array(encoder, this.lenEncoder.toUint8Array())
+    // @note The rest encoder is appended! (note the missing var)
+    encoding.writeUint8Array(encoder, encoding.toUint8Array(this.restEncoder))
+    return encoding.toUint8Array(encoder)
+  }
+
+  /**
+   * @param {ID} id
+   */
+  writeLeftID (id) {
+    this.clientEncoder.write(id.client)
+    this.leftClockEncoder.write(id.clock)
+  }
+
+  /**
+   * @param {ID} id
+   */
+  writeRightID (id) {
+    this.clientEncoder.write(id.client)
+    this.rightClockEncoder.write(id.clock)
+  }
+
+  /**
+   * @param {number} client
+   */
+  writeClient (client) {
+    this.clientEncoder.write(client)
+  }
+
+  /**
+   * @param {number} info An unsigned 8-bit integer
+   */
+  writeInfo (info) {
+    this.infoEncoder.write(info)
+  }
+
+  /**
+   * @param {string} s
+   */
+  writeString (s) {
+    this.stringEncoder.write(s)
+  }
+
+  /**
+   * @param {boolean} isYKey
+   */
+  writeParentInfo (isYKey) {
+    this.parentInfoEncoder.write(isYKey ? 1 : 0)
+  }
+
+  /**
+   * @param {number} info An unsigned 8-bit integer
+   */
+  writeTypeRef (info) {
+    this.typeRefEncoder.write(info)
+  }
+
+  /**
+   * Write len of a struct - well suited for Opt RLE encoder.
+   *
+   * @param {number} len
+   */
+  writeLen (len) {
+    this.lenEncoder.write(len)
+  }
+
+  /**
+   * @param {any} any
+   */
+  writeAny (any) {
+    encoding.writeAny(this.restEncoder, any)
+  }
+
+  /**
+   * @param {Uint8Array} buf
+   */
+  writeBuf (buf) {
+    encoding.writeVarUint8Array(this.restEncoder, buf)
+  }
+
+  /**
+   * This is mainly here for legacy purposes.
+   *
+   * Initial we incoded objects using JSON. Now we use the much faster lib0/any-encoder. This method mainly exists for legacy purposes for the v1 encoder.
+   *
+   * @param {any} embed
+   */
+  writeJSON (embed) {
+    encoding.writeAny(this.restEncoder, embed)
+  }
+
+  /**
+   * Property keys are often reused. For example, in y-prosemirror the key `bold` might
+   * occur very often. For a 3d application, the key `position` might occur very often.
+   *
+   * We cache these keys in a Map and refer to them via a unique number.
+   *
+   * @param {string} key
+   */
+  writeKey (key) {
+    const clock = this.keyMap.get(key)
+    if (clock === undefined) {
+      /**
+       * @todo uncomment to introduce this feature finally
+       *
+       * Background. The ContentFormat object was always encoded using writeKey, but the decoder used to use readString.
+       * Furthermore, I forgot to set the keyclock. So everything was working fine.
+       *
+       * However, this feature here is basically useless as it is not being used (it actually only consumes extra memory).
+       *
+       * I don't know yet how to reintroduce this feature..
+       *
+       * Older clients won't be able to read updates when we reintroduce this feature. So this should probably be done using a flag.
+       *
+       */
+      // this.keyMap.set(key, this.keyClock)
+      this.keyClockEncoder.write(this.keyClock++)
+      this.stringEncoder.write(key)
+    } else {
+      this.keyClockEncoder.write(clock)
+    }
+  }
+}

src/utils/YEvent.js

@@ -4,21 +4,22 @@ import {
   Item, AbstractType, Transaction, AbstractStruct // eslint-disable-line
 } from '../internals.js'
 
-import * as set from 'lib0/set.js'
-import * as array from 'lib0/array.js'
+import * as set from 'lib0/set'
+import * as array from 'lib0/array'
 
 /**
+ * @template {AbstractType<any>} T
  * YEvent describes the changes on a YType.
  */
 export class YEvent {
   /**
-   * @param {AbstractType<any>} target The changed type.
+   * @param {T} target The changed type.
    * @param {Transaction} transaction
    */
   constructor (target, transaction) {
     /**
      * The type on which this event was created on.
-     * @type {AbstractType<any>}
+     * @type {T}
      */
     this.target = target
     /**
@@ -35,11 +36,21 @@ export class YEvent {
      * @type {Object|null}
      */
     this._changes = null
+    /**
+     * @type {null | Map<string, { action: 'add' | 'update' | 'delete', oldValue: any, newValue: any }>}
+     */
+    this._keys = null
+    /**
+     * @type {null | Array<{ insert?: string | Array<any> | object | AbstractType<any>, retain?: number, delete?: number, attributes?: Object<string, any> }>}
+     */
+    this._delta = null
   }
 
   /**
    * Computes the path from `y` to the changed type.
    *
+   * @todo v14 should standardize on path: Array<{parent, index}> because that is easier to work with.
+   *
    * The following property holds:
    * @example
    *   let type = y
@@ -65,6 +76,66 @@ export class YEvent {
     return isDeleted(this.transaction.deleteSet, struct.id)
   }
 
+  /**
+   * @type {Map<string, { action: 'add' | 'update' | 'delete', oldValue: any, newValue: any }>}
+   */
+  get keys () {
+    if (this._keys === null) {
+      const keys = new Map()
+      const target = this.target
+      const changed = /** @type Set<string|null> */ (this.transaction.changed.get(target))
+      changed.forEach(key => {
+        if (key !== null) {
+          const item = /** @type {Item} */ (target._map.get(key))
+          /**
+           * @type {'delete' | 'add' | 'update'}
+           */
+          let action
+          let oldValue
+          if (this.adds(item)) {
+            let prev = item.left
+            while (prev !== null && this.adds(prev)) {
+              prev = prev.left
+            }
+            if (this.deletes(item)) {
+              if (prev !== null && this.deletes(prev)) {
+                action = 'delete'
+                oldValue = array.last(prev.content.getContent())
+              } else {
+                return
+              }
+            } else {
+              if (prev !== null && this.deletes(prev)) {
+                action = 'update'
+                oldValue = array.last(prev.content.getContent())
+              } else {
+                action = 'add'
+                oldValue = undefined
+              }
+            }
+          } else {
+            if (this.deletes(item)) {
+              action = 'delete'
+              oldValue = array.last(/** @type {Item} */ item.content.getContent())
+            } else {
+              return // nop
+            }
+          }
+          keys.set(key, { action, oldValue })
+        }
+      })
+      this._keys = keys
+    }
+    return this._keys
+  }
+
+  /**
+   * @type {Array<{insert?: string | Array<any> | object | AbstractType<any>, retain?: number, delete?: number, attributes?: Object<string, any>}>}
+   */
+  get delta () {
+    return this.changes.delta
+  }
+
   /**
    * Check if a struct is added by this event.
    *
@@ -78,7 +149,7 @@ export class YEvent {
   }
 
   /**
-   * @return {{added:Set<Item>,deleted:Set<Item>,delta:Array<{insert:Array<any>}|{delete:number}|{retain:number}>}}
+   * @type {{added:Set<Item>,deleted:Set<Item>,keys:Map<string,{action:'add'|'update'|'delete',oldValue:any}>,delta:Array<{insert?:Array<any>|string, delete?:number, retain?:number}>}}
    */
   get changes () {
     let changes = this._changes
@@ -90,12 +161,11 @@ export class YEvent {
        * @type {Array<{insert:Array<any>}|{delete:number}|{retain:number}>}
        */
       const delta = []
-      /**
-       * @type {Map<string,{ action: 'add' | 'update' | 'delete', oldValue: any}>}
-       */
-      const keys = new Map()
       changes = {
-        added, deleted, delta, keys
+        added,
+        deleted,
+        delta,
+        keys: this.keys
       }
       const changed = /** @type Set<string|null> */ (this.transaction.changed.get(target))
       if (changed.has(null)) {
@@ -139,46 +209,6 @@ export class YEvent {
           packOp()
         }
       }
-      changed.forEach(key => {
-        if (key !== null) {
-          const item = /** @type {Item} */ (target._map.get(key))
-          /**
-           * @type {'delete' | 'add' | 'update'}
-           */
-          let action
-          let oldValue
-          if (this.adds(item)) {
-            let prev = item.left
-            while (prev !== null && this.adds(prev)) {
-              prev = prev.left
-            }
-            if (this.deletes(item)) {
-              if (prev !== null && this.deletes(prev)) {
-                action = 'delete'
-                oldValue = array.last(prev.content.getContent())
-              } else {
-                return
-              }
-            } else {
-              if (prev !== null && this.deletes(prev)) {
-                action = 'update'
-                oldValue = array.last(prev.content.getContent())
-              } else {
-                action = 'add'
-                oldValue = undefined
-              }
-            }
-          } else {
-            if (this.deletes(item)) {
-              action = 'delete'
-              oldValue = array.last(/** @type {Item} */ item.content.getContent())
-            } else {
-              return // nop
-            }
-          }
-          keys.set(key, { action, oldValue })
-        }
-      })
       this._changes = changes
     }
     return /** @type {any} */ (changes)
@@ -211,7 +241,7 @@ const getPathTo = (parent, child) => {
     } else {
       // parent is array-ish
       let i = 0
-      let c = child._item.parent._start
+      let c = /** @type {AbstractType<any>} */ (child._item.parent)._start
       while (c !== child._item && c !== null) {
         if (!c.deleted) {
           i++
@@ -220,7 +250,7 @@ const getPathTo = (parent, child) => {
       }
       path.unshift(i)
     }
-    child = child._item.parent
+    child = /** @type {AbstractType<any>} */ (child._item.parent)
   }
   return path
 }

src/utils/encoding.js

@@ -1,7 +1,8 @@
 
 /**
  * @module encoding
- *
+ */
+/*
  * We use the first five bits in the info flag for determining the type of the struct.
  *
  * 0: GC
@@ -16,27 +17,39 @@
 
 import {
   findIndexSS,
-  GCRef,
-  ItemRef,
-  writeID,
-  createID,
-  readID,
   getState,
+  createID,
   getStateVector,
   readAndApplyDeleteSet,
   writeDeleteSet,
   createDeleteSetFromStructStore,
   transact,
-  Doc, Transaction, AbstractStruct, StructStore, ID // eslint-disable-line
+  readItemContent,
+  UpdateDecoderV1,
+  UpdateDecoderV2,
+  UpdateEncoderV1,
+  UpdateEncoderV2,
+  DSEncoderV2,
+  DSDecoderV1,
+  DSEncoderV1,
+  mergeUpdates,
+  mergeUpdatesV2,
+  Skip,
+  diffUpdateV2,
+  convertUpdateFormatV2ToV1,
+  DSDecoderV2, Doc, Transaction, GC, Item, StructStore // eslint-disable-line
 } from '../internals.js'
 
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-import * as binary from 'lib0/binary.js'
+import * as encoding from 'lib0/encoding'
+import * as decoding from 'lib0/decoding'
+import * as binary from 'lib0/binary'
+import * as map from 'lib0/map'
+import * as math from 'lib0/math'
+import * as array from 'lib0/array'
 
 /**
- * @param {encoding.Encoder} encoder
- * @param {Array<AbstractStruct>} structs All structs by `client`
+ * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
+ * @param {Array<GC|Item>} structs All structs by `client`
  * @param {number} client
  * @param {number} clock write structs starting with `ID(client,clock)`
  *
@@ -44,43 +57,22 @@ import * as binary from 'lib0/binary.js'
  */
 const writeStructs = (encoder, structs, client, clock) => {
   // write first id
+  clock = math.max(clock, structs[0].id.clock) // make sure the first id exists
   const startNewStructs = findIndexSS(structs, clock)
   // write # encoded structs
-  encoding.writeVarUint(encoder, structs.length - startNewStructs)
-  writeID(encoder, createID(client, clock))
+  encoding.writeVarUint(encoder.restEncoder, structs.length - startNewStructs)
+  encoder.writeClient(client)
+  encoding.writeVarUint(encoder.restEncoder, clock)
   const firstStruct = structs[startNewStructs]
   // write first struct with an offset
-  firstStruct.write(encoder, clock - firstStruct.id.clock, 0)
+  firstStruct.write(encoder, clock - firstStruct.id.clock)
   for (let i = startNewStructs + 1; i < structs.length; i++) {
-    structs[i].write(encoder, 0, 0)
+    structs[i].write(encoder, 0)
   }
 }
 
 /**
- * @param {decoding.Decoder} decoder
- * @param {number} numOfStructs
- * @param {ID} nextID
- * @return {Array<GCRef|ItemRef>}
- *
- * @private
- * @function
- */
-const readStructRefs = (decoder, numOfStructs, nextID) => {
-  /**
-   * @type {Array<GCRef|ItemRef>}
-   */
-  const refs = []
-  for (let i = 0; i < numOfStructs; i++) {
-    const info = decoding.readUint8(decoder)
-    const ref = (binary.BITS5 & info) === 0 ? new GCRef(decoder, nextID, info) : new ItemRef(decoder, nextID, info)
-    nextID = createID(nextID.client, nextID.clock + ref.length)
-    refs.push(ref)
-  }
-  return refs
-}
-
-/**
- * @param {encoding.Encoder} encoder
+ * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
  * @param {StructStore} store
  * @param {Map<number,number>} _sm
  *
@@ -102,31 +94,107 @@ export const writeClientsStructs = (encoder, store, _sm) => {
     }
   })
   // write # states that were updated
-  encoding.writeVarUint(encoder, sm.size)
-  sm.forEach((clock, client) => {
+  encoding.writeVarUint(encoder.restEncoder, sm.size)
+  // Write items with higher client ids first
+  // This heavily improves the conflict algorithm.
+  array.from(sm.entries()).sort((a, b) => b[0] - a[0]).forEach(([client, clock]) => {
     // @ts-ignore
     writeStructs(encoder, store.clients.get(client), client, clock)
   })
 }
 
 /**
- * @param {decoding.Decoder} decoder The decoder object to read data from.
- * @return {Map<number,Array<GCRef|ItemRef>>}
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder The decoder object to read data from.
+ * @param {Doc} doc
+ * @return {Map<number, { i: number, refs: Array<Item | GC> }>}
  *
  * @private
  * @function
  */
-export const readClientsStructRefs = decoder => {
+export const readClientsStructRefs = (decoder, doc) => {
   /**
-   * @type {Map<number,Array<GCRef|ItemRef>>}
+   * @type {Map<number, { i: number, refs: Array<Item | GC> }>}
    */
-  const clientRefs = new Map()
-  const numOfStateUpdates = decoding.readVarUint(decoder)
+  const clientRefs = map.create()
+  const numOfStateUpdates = decoding.readVarUint(decoder.restDecoder)
   for (let i = 0; i < numOfStateUpdates; i++) {
-    const numberOfStructs = decoding.readVarUint(decoder)
-    const nextID = readID(decoder)
-    const refs = readStructRefs(decoder, numberOfStructs, nextID)
-    clientRefs.set(nextID.client, refs)
+    const numberOfStructs = decoding.readVarUint(decoder.restDecoder)
+    /**
+     * @type {Array<GC|Item>}
+     */
+    const refs = new Array(numberOfStructs)
+    const client = decoder.readClient()
+    let clock = decoding.readVarUint(decoder.restDecoder)
+    // const start = performance.now()
+    clientRefs.set(client, { i: 0, refs })
+    for (let i = 0; i < numberOfStructs; i++) {
+      const info = decoder.readInfo()
+      switch (binary.BITS5 & info) {
+        case 0: { // GC
+          const len = decoder.readLen()
+          refs[i] = new GC(createID(client, clock), len)
+          clock += len
+          break
+        }
+        case 10: { // Skip Struct (nothing to apply)
+          // @todo we could reduce the amount of checks by adding Skip struct to clientRefs so we know that something is missing.
+          const len = decoding.readVarUint(decoder.restDecoder)
+          refs[i] = new Skip(createID(client, clock), len)
+          clock += len
+          break
+        }
+        default: { // Item with content
+          /**
+           * The optimized implementation doesn't use any variables because inlining variables is faster.
+           * Below a non-optimized version is shown that implements the basic algorithm with
+           * a few comments
+           */
+          const cantCopyParentInfo = (info & (binary.BIT7 | binary.BIT8)) === 0
+          // If parent = null and neither left nor right are defined, then we know that `parent` is child of `y`
+          // and we read the next string as parentYKey.
+          // It indicates how we store/retrieve parent from `y.share`
+          // @type {string|null}
+          const struct = new Item(
+            createID(client, clock),
+            null, // leftd
+            (info & binary.BIT8) === binary.BIT8 ? decoder.readLeftID() : null, // origin
+            null, // right
+            (info & binary.BIT7) === binary.BIT7 ? decoder.readRightID() : null, // right origin
+            cantCopyParentInfo ? (decoder.readParentInfo() ? doc.get(decoder.readString()) : decoder.readLeftID()) : null, // parent
+            cantCopyParentInfo && (info & binary.BIT6) === binary.BIT6 ? decoder.readString() : null, // parentSub
+            readItemContent(decoder, info) // item content
+          )
+          /* A non-optimized implementation of the above algorithm:
+
+          // The item that was originally to the left of this item.
+          const origin = (info & binary.BIT8) === binary.BIT8 ? decoder.readLeftID() : null
+          // The item that was originally to the right of this item.
+          const rightOrigin = (info & binary.BIT7) === binary.BIT7 ? decoder.readRightID() : null
+          const cantCopyParentInfo = (info & (binary.BIT7 | binary.BIT8)) === 0
+          const hasParentYKey = cantCopyParentInfo ? decoder.readParentInfo() : false
+          // If parent = null and neither left nor right are defined, then we know that `parent` is child of `y`
+          // and we read the next string as parentYKey.
+          // It indicates how we store/retrieve parent from `y.share`
+          // @type {string|null}
+          const parentYKey = cantCopyParentInfo && hasParentYKey ? decoder.readString() : null
+
+          const struct = new Item(
+            createID(client, clock),
+            null, // leftd
+            origin, // origin
+            null, // right
+            rightOrigin, // right origin
+            cantCopyParentInfo && !hasParentYKey ? decoder.readLeftID() : (parentYKey !== null ? doc.get(parentYKey) : null), // parent
+            cantCopyParentInfo && (info & binary.BIT6) === binary.BIT6 ? decoder.readString() : null, // parentSub
+            readItemContent(decoder, info) // item content
+          )
+          */
+          refs[i] = struct
+          clock += struct.length
+        }
+      }
+    }
+    // console.log('time to read: ', performance.now() - start) // @todo remove
   }
   return clientRefs
 }
@@ -152,91 +220,148 @@ export const readClientsStructRefs = decoder => {
  *
  * @param {Transaction} transaction
  * @param {StructStore} store
+ * @param {Map<number, { i: number, refs: (GC | Item)[] }>} clientsStructRefs
+ * @return { null | { update: Uint8Array, missing: Map<number,number> } }
  *
  * @private
  * @function
  */
-const resumeStructIntegration = (transaction, store) => {
-  const stack = store.pendingStack
-  const clientsStructRefs = store.pendingClientsStructRefs
-  // iterate over all struct readers until we are done
-  while (stack.length !== 0 || clientsStructRefs.size !== 0) {
-    if (stack.length === 0) {
-      // take any first struct from clientsStructRefs and put it on the stack
-      const [client, structRefs] = clientsStructRefs.entries().next().value
-      stack.push(structRefs.refs[structRefs.i++])
-      if (structRefs.refs.length === structRefs.i) {
+const integrateStructs = (transaction, store, clientsStructRefs) => {
+  /**
+   * @type {Array<Item | GC>}
+   */
+  const stack = []
+  // sort them so that we take the higher id first, in case of conflicts the lower id will probably not conflict with the id from the higher user.
+  let clientsStructRefsIds = array.from(clientsStructRefs.keys()).sort((a, b) => a - b)
+  if (clientsStructRefsIds.length === 0) {
+    return null
+  }
+  const getNextStructTarget = () => {
+    if (clientsStructRefsIds.length === 0) {
+      return null
+    }
+    let nextStructsTarget = /** @type {{i:number,refs:Array<GC|Item>}} */ (clientsStructRefs.get(clientsStructRefsIds[clientsStructRefsIds.length - 1]))
+    while (nextStructsTarget.refs.length === nextStructsTarget.i) {
+      clientsStructRefsIds.pop()
+      if (clientsStructRefsIds.length > 0) {
+        nextStructsTarget = /** @type {{i:number,refs:Array<GC|Item>}} */ (clientsStructRefs.get(clientsStructRefsIds[clientsStructRefsIds.length - 1]))
+      } else {
+        return null
+      }
+    }
+    return nextStructsTarget
+  }
+  let curStructsTarget = getNextStructTarget()
+  if (curStructsTarget === null && stack.length === 0) {
+    return null
+  }
+
+  /**
+   * @type {StructStore}
+   */
+  const restStructs = new StructStore()
+  const missingSV = new Map()
+  /**
+   * @param {number} client
+   * @param {number} clock
+   */
+  const updateMissingSv = (client, clock) => {
+    const mclock = missingSV.get(client)
+    if (mclock == null || mclock > clock) {
+      missingSV.set(client, clock)
+    }
+  }
+  /**
+   * @type {GC|Item}
+   */
+  let stackHead = /** @type {any} */ (curStructsTarget).refs[/** @type {any} */ (curStructsTarget).i++]
+  // caching the state because it is used very often
+  const state = new Map()
+
+  const addStackToRestSS = () => {
+    for (const item of stack) {
+      const client = item.id.client
+      const unapplicableItems = clientsStructRefs.get(client)
+      if (unapplicableItems) {
+        // decrement because we weren't able to apply previous operation
+        unapplicableItems.i--
+        restStructs.clients.set(client, unapplicableItems.refs.slice(unapplicableItems.i))
         clientsStructRefs.delete(client)
+        unapplicableItems.i = 0
+        unapplicableItems.refs = []
+      } else {
+        // item was the last item on clientsStructRefs and the field was already cleared. Add item to restStructs and continue
+        restStructs.clients.set(client, [item])
+      }
+      // remove client from clientsStructRefsIds to prevent users from applying the same update again
+      clientsStructRefsIds = clientsStructRefsIds.filter(c => c !== client)
+    }
+    stack.length = 0
+  }
+
+  // iterate over all struct readers until we are done
+  while (true) {
+    if (stackHead.constructor !== Skip) {
+      const localClock = map.setIfUndefined(state, stackHead.id.client, () => getState(store, stackHead.id.client))
+      const offset = localClock - stackHead.id.clock
+      if (offset < 0) {
+        // update from the same client is missing
+        stack.push(stackHead)
+        updateMissingSv(stackHead.id.client, stackHead.id.clock - 1)
+        // hid a dead wall, add all items from stack to restSS
+        addStackToRestSS()
+      } else {
+        const missing = stackHead.getMissing(transaction, store)
+        if (missing !== null) {
+          stack.push(stackHead)
+          // get the struct reader that has the missing struct
+          /**
+           * @type {{ refs: Array<GC|Item>, i: number }}
+           */
+          const structRefs = clientsStructRefs.get(/** @type {number} */ (missing)) || { refs: [], i: 0 }
+          if (structRefs.refs.length === structRefs.i) {
+            // This update message causally depends on another update message that doesn't exist yet
+            updateMissingSv(/** @type {number} */ (missing), getState(store, missing))
+            addStackToRestSS()
+          } else {
+            stackHead = structRefs.refs[structRefs.i++]
+            continue
+          }
+        } else if (offset === 0 || offset < stackHead.length) {
+          // all fine, apply the stackhead
+          stackHead.integrate(transaction, offset)
+          state.set(stackHead.id.client, stackHead.id.clock + stackHead.length)
+        }
       }
     }
-    const ref = stack[stack.length - 1]
-    const m = ref._missing
-    const client = ref.id.client
-    const localClock = getState(store, client)
-    const offset = ref.id.clock < localClock ? localClock - ref.id.clock : 0
-    if (ref.id.clock + offset !== localClock) {
-      // A previous message from this client is missing
-      // check if there is a pending structRef with a smaller clock and switch them
-      const structRefs = clientsStructRefs.get(client)
-      if (structRefs !== undefined) {
-        const r = structRefs.refs[structRefs.i]
-        if (r.id.clock < ref.id.clock) {
-          // put ref with smaller clock on stack instead and continue
-          structRefs.refs[structRefs.i] = ref
-          stack[stack.length - 1] = r
-          // sort the set because this approach might bring the list out of order
-          structRefs.refs = structRefs.refs.slice(structRefs.i).sort((r1, r2) => r1.id.clock - r2.id.clock)
-          structRefs.i = 0
-          continue
-        }
-      }
-      // wait until missing struct is available
-      return
-    }
-    while (m.length > 0) {
-      const missing = m[m.length - 1]
-      if (getState(store, missing.client) <= missing.clock) {
-        const client = missing.client
-        // get the struct reader that has the missing struct
-        const structRefs = clientsStructRefs.get(client)
-        if (structRefs === undefined) {
-          // This update message causally depends on another update message.
-          return
-        }
-        stack.push(structRefs.refs[structRefs.i++])
-        if (structRefs.i === structRefs.refs.length) {
-          clientsStructRefs.delete(client)
-        }
+    // iterate to next stackHead
+    if (stack.length > 0) {
+      stackHead = /** @type {GC|Item} */ (stack.pop())
+    } else if (curStructsTarget !== null && curStructsTarget.i < curStructsTarget.refs.length) {
+      stackHead = /** @type {GC|Item} */ (curStructsTarget.refs[curStructsTarget.i++])
+    } else {
+      curStructsTarget = getNextStructTarget()
+      if (curStructsTarget === null) {
+        // we are done!
         break
+      } else {
+        stackHead = /** @type {GC|Item} */ (curStructsTarget.refs[curStructsTarget.i++])
       }
-      ref._missing.pop()
-    }
-    if (m.length === 0) {
-      if (offset < ref.length) {
-        ref.toStruct(transaction, store, offset).integrate(transaction)
-      }
-      stack.pop()
     }
   }
+  if (restStructs.clients.size > 0) {
+    const encoder = new UpdateEncoderV2()
+    writeClientsStructs(encoder, restStructs, new Map())
+    // write empty deleteset
+    // writeDeleteSet(encoder, new DeleteSet())
+    encoding.writeVarUint(encoder.restEncoder, 0) // => no need for an extra function call, just write 0 deletes
+    return { missing: missingSV, update: encoder.toUint8Array() }
+  }
+  return null
 }
 
 /**
- * @param {Transaction} transaction
- * @param {StructStore} store
- *
- * @private
- * @function
- */
-export const tryResumePendingDeleteReaders = (transaction, store) => {
-  const pendingReaders = store.pendingDeleteReaders
-  store.pendingDeleteReaders = []
-  for (let i = 0; i < pendingReaders.length; i++) {
-    readAndApplyDeleteSet(pendingReaders[i], transaction, store)
-  }
-}
-
-/**
- * @param {encoding.Encoder} encoder
+ * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
  * @param {Transaction} transaction
  *
  * @private
@@ -245,48 +370,85 @@ export const tryResumePendingDeleteReaders = (transaction, store) => {
 export const writeStructsFromTransaction = (encoder, transaction) => writeClientsStructs(encoder, transaction.doc.store, transaction.beforeState)
 
 /**
- * @param {StructStore} store
- * @param {Map<number, Array<GCRef|ItemRef>>} clientsStructsRefs
+ * Read and apply a document update.
+ *
+ * This function has the same effect as `applyUpdate` but accepts an decoder.
+ *
+ * @param {decoding.Decoder} decoder
+ * @param {Doc} ydoc
+ * @param {any} [transactionOrigin] This will be stored on `transaction.origin` and `.on('update', (update, origin))`
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} [structDecoder]
  *
- * @private
  * @function
  */
-const mergeReadStructsIntoPendingReads = (store, clientsStructsRefs) => {
-  const pendingClientsStructRefs = store.pendingClientsStructRefs
-  for (const [client, structRefs] of clientsStructsRefs) {
-    const pendingStructRefs = pendingClientsStructRefs.get(client)
-    if (pendingStructRefs === undefined) {
-      pendingClientsStructRefs.set(client, { refs: structRefs, i: 0 })
-    } else {
-      // merge into existing structRefs
-      const merged = pendingStructRefs.i > 0 ? pendingStructRefs.refs.slice(pendingStructRefs.i) : pendingStructRefs.refs
-      for (let i = 0; i < structRefs.length; i++) {
-        merged.push(structRefs[i])
+export const readUpdateV2 = (decoder, ydoc, transactionOrigin, structDecoder = new UpdateDecoderV2(decoder)) =>
+  transact(ydoc, transaction => {
+    // force that transaction.local is set to non-local
+    transaction.local = false
+    let retry = false
+    const doc = transaction.doc
+    const store = doc.store
+    // let start = performance.now()
+    const ss = readClientsStructRefs(structDecoder, doc)
+    // console.log('time to read structs: ', performance.now() - start) // @todo remove
+    // start = performance.now()
+    // console.log('time to merge: ', performance.now() - start) // @todo remove
+    // start = performance.now()
+    const restStructs = integrateStructs(transaction, store, ss)
+    const pending = store.pendingStructs
+    if (pending) {
+      // check if we can apply something
+      for (const [client, clock] of pending.missing) {
+        if (clock < getState(store, client)) {
+          retry = true
+          break
+        }
       }
-      pendingStructRefs.i = 0
-      pendingStructRefs.refs = merged.sort((r1, r2) => r1.id.clock - r2.id.clock)
+      if (restStructs) {
+        // merge restStructs into store.pending
+        for (const [client, clock] of restStructs.missing) {
+          const mclock = pending.missing.get(client)
+          if (mclock == null || mclock > clock) {
+            pending.missing.set(client, clock)
+          }
+        }
+        pending.update = mergeUpdatesV2([pending.update, restStructs.update])
+      }
+    } else {
+      store.pendingStructs = restStructs
     }
-  }
-}
+    // console.log('time to integrate: ', performance.now() - start) // @todo remove
+    // start = performance.now()
+    const dsRest = readAndApplyDeleteSet(structDecoder, transaction, store)
+    if (store.pendingDs) {
+      // @todo we could make a lower-bound state-vector check as we do above
+      const pendingDSUpdate = new UpdateDecoderV2(decoding.createDecoder(store.pendingDs))
+      decoding.readVarUint(pendingDSUpdate.restDecoder) // read 0 structs, because we only encode deletes in pendingdsupdate
+      const dsRest2 = readAndApplyDeleteSet(pendingDSUpdate, transaction, store)
+      if (dsRest && dsRest2) {
+        // case 1: ds1 != null && ds2 != null
+        store.pendingDs = mergeUpdatesV2([dsRest, dsRest2])
+      } else {
+        // case 2: ds1 != null
+        // case 3: ds2 != null
+        // case 4: ds1 == null && ds2 == null
+        store.pendingDs = dsRest || dsRest2
+      }
+    } else {
+      // Either dsRest == null && pendingDs == null OR dsRest != null
+      store.pendingDs = dsRest
+    }
+    // console.log('time to cleanup: ', performance.now() - start) // @todo remove
+    // start = performance.now()
 
-/**
- * Read the next Item in a Decoder and fill this Item with the read data.
- *
- * This is called when data is received from a remote peer.
- *
- * @param {decoding.Decoder} decoder The decoder object to read data from.
- * @param {Transaction} transaction
- * @param {StructStore} store
- *
- * @private
- * @function
- */
-export const readStructs = (decoder, transaction, store) => {
-  const clientsStructRefs = readClientsStructRefs(decoder)
-  mergeReadStructsIntoPendingReads(store, clientsStructRefs)
-  resumeStructIntegration(transaction, store)
-  tryResumePendingDeleteReaders(transaction, store)
-}
+    // console.log('time to resume delete readers: ', performance.now() - start) // @todo remove
+    // start = performance.now()
+    if (retry) {
+      const update = /** @type {{update: Uint8Array}} */ (store.pendingStructs).update
+      store.pendingStructs = null
+      applyUpdateV2(transaction.doc, update)
+    }
+  }, transactionOrigin, false)
 
 /**
  * Read and apply a document update.
@@ -299,11 +461,24 @@ export const readStructs = (decoder, transaction, store) => {
  *
  * @function
  */
-export const readUpdate = (decoder, ydoc, transactionOrigin) =>
-  transact(ydoc, transaction => {
-    readStructs(decoder, transaction, ydoc.store)
-    readAndApplyDeleteSet(decoder, transaction, ydoc.store)
-  }, transactionOrigin, false)
+export const readUpdate = (decoder, ydoc, transactionOrigin) => readUpdateV2(decoder, ydoc, transactionOrigin, new UpdateDecoderV1(decoder))
+
+/**
+ * Apply a document update created by, for example, `y.on('update', update => ..)` or `update = encodeStateAsUpdate()`.
+ *
+ * This function has the same effect as `readUpdate` but accepts an Uint8Array instead of a Decoder.
+ *
+ * @param {Doc} ydoc
+ * @param {Uint8Array} update
+ * @param {any} [transactionOrigin] This will be stored on `transaction.origin` and `.on('update', (update, origin))`
+ * @param {typeof UpdateDecoderV1 | typeof UpdateDecoderV2} [YDecoder]
+ *
+ * @function
+ */
+export const applyUpdateV2 = (ydoc, update, transactionOrigin, YDecoder = UpdateDecoderV2) => {
+  const decoder = decoding.createDecoder(update)
+  readUpdateV2(decoder, ydoc, transactionOrigin, new YDecoder(decoder))
+}
 
 /**
  * Apply a document update created by, for example, `y.on('update', update => ..)` or `update = encodeStateAsUpdate()`.
@@ -316,14 +491,13 @@ export const readUpdate = (decoder, ydoc, transactionOrigin) =>
  *
  * @function
  */
-export const applyUpdate = (ydoc, update, transactionOrigin) =>
-  readUpdate(decoding.createDecoder(update), ydoc, transactionOrigin)
+export const applyUpdate = (ydoc, update, transactionOrigin) => applyUpdateV2(ydoc, update, transactionOrigin, UpdateDecoderV1)
 
 /**
  * Write all the document as a single update message. If you specify the state of the remote client (`targetStateVector`) it will
  * only write the operations that are missing.
  *
- * @param {encoding.Encoder} encoder
+ * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
  * @param {Doc} doc
  * @param {Map<number,number>} [targetStateVector] The state of the target that receives the update. Leave empty to write all known structs
  *
@@ -342,31 +516,60 @@ export const writeStateAsUpdate = (encoder, doc, targetStateVector = new Map())
  *
  * @param {Doc} doc
  * @param {Uint8Array} [encodedTargetStateVector] The state of the target that receives the update. Leave empty to write all known structs
+ * @param {UpdateEncoderV1 | UpdateEncoderV2} [encoder]
  * @return {Uint8Array}
  *
  * @function
  */
-export const encodeStateAsUpdate = (doc, encodedTargetStateVector) => {
-  const encoder = encoding.createEncoder()
-  const targetStateVector = encodedTargetStateVector == null ? new Map() : decodeStateVector(encodedTargetStateVector)
+export const encodeStateAsUpdateV2 = (doc, encodedTargetStateVector = new Uint8Array([0]), encoder = new UpdateEncoderV2()) => {
+  const targetStateVector = decodeStateVector(encodedTargetStateVector)
   writeStateAsUpdate(encoder, doc, targetStateVector)
-  return encoding.toUint8Array(encoder)
+  const updates = [encoder.toUint8Array()]
+  // also add the pending updates (if there are any)
+  if (doc.store.pendingDs) {
+    updates.push(doc.store.pendingDs)
+  }
+  if (doc.store.pendingStructs) {
+    updates.push(diffUpdateV2(doc.store.pendingStructs.update, encodedTargetStateVector))
+  }
+  if (updates.length > 1) {
+    if (encoder.constructor === UpdateEncoderV1) {
+      return mergeUpdates(updates.map((update, i) => i === 0 ? update : convertUpdateFormatV2ToV1(update)))
+    } else if (encoder.constructor === UpdateEncoderV2) {
+      return mergeUpdatesV2(updates)
+    }
+  }
+  return updates[0]
 }
 
+/**
+ * Write all the document as a single update message that can be applied on the remote document. If you specify the state of the remote client (`targetState`) it will
+ * only write the operations that are missing.
+ *
+ * Use `writeStateAsUpdate` instead if you are working with lib0/encoding.js#Encoder
+ *
+ * @param {Doc} doc
+ * @param {Uint8Array} [encodedTargetStateVector] The state of the target that receives the update. Leave empty to write all known structs
+ * @return {Uint8Array}
+ *
+ * @function
+ */
+export const encodeStateAsUpdate = (doc, encodedTargetStateVector) => encodeStateAsUpdateV2(doc, encodedTargetStateVector, new UpdateEncoderV1())
+
 /**
  * Read state vector from Decoder and return as Map
  *
- * @param {decoding.Decoder} decoder
+ * @param {DSDecoderV1 | DSDecoderV2} decoder
  * @return {Map<number,number>} Maps `client` to the number next expected `clock` from that client.
  *
  * @function
  */
 export const readStateVector = decoder => {
   const ss = new Map()
-  const ssLength = decoding.readVarUint(decoder)
+  const ssLength = decoding.readVarUint(decoder.restDecoder)
   for (let i = 0; i < ssLength; i++) {
-    const client = decoding.readVarUint(decoder)
-    const clock = decoding.readVarUint(decoder)
+    const client = decoding.readVarUint(decoder.restDecoder)
+    const clock = decoding.readVarUint(decoder.restDecoder)
     ss.set(client, clock)
   }
   return ss
@@ -380,28 +583,34 @@ export const readStateVector = decoder => {
  *
  * @function
  */
-export const decodeStateVector = decodedState => readStateVector(decoding.createDecoder(decodedState))
+// export const decodeStateVectorV2 = decodedState => readStateVector(new DSDecoderV2(decoding.createDecoder(decodedState)))
 
 /**
- * Write State Vector to `lib0/encoding.js#Encoder`.
+ * Read decodedState and return State as Map.
  *
- * @param {encoding.Encoder} encoder
+ * @param {Uint8Array} decodedState
+ * @return {Map<number,number>} Maps `client` to the number next expected `clock` from that client.
+ *
+ * @function
+ */
+export const decodeStateVector = decodedState => readStateVector(new DSDecoderV1(decoding.createDecoder(decodedState)))
+
+/**
+ * @param {DSEncoderV1 | DSEncoderV2} encoder
  * @param {Map<number,number>} sv
  * @function
  */
 export const writeStateVector = (encoder, sv) => {
-  encoding.writeVarUint(encoder, sv.size)
-  sv.forEach((clock, client) => {
-    encoding.writeVarUint(encoder, client)
-    encoding.writeVarUint(encoder, clock)
+  encoding.writeVarUint(encoder.restEncoder, sv.size)
+  array.from(sv.entries()).sort((a, b) => b[0] - a[0]).forEach(([client, clock]) => {
+    encoding.writeVarUint(encoder.restEncoder, client) // @todo use a special client decoder that is based on mapping
+    encoding.writeVarUint(encoder.restEncoder, clock)
   })
   return encoder
 }
 
 /**
- * Write State Vector to `lib0/encoding.js#Encoder`.
- *
- * @param {encoding.Encoder} encoder
+ * @param {DSEncoderV1 | DSEncoderV2} encoder
  * @param {Doc} doc
  *
  * @function
@@ -411,13 +620,27 @@ export const writeDocumentStateVector = (encoder, doc) => writeStateVector(encod
 /**
  * Encode State as Uint8Array.
  *
- * @param {Doc} doc
+ * @param {Doc|Map<number,number>} doc
+ * @param {DSEncoderV1 | DSEncoderV2} [encoder]
  * @return {Uint8Array}
  *
  * @function
  */
-export const encodeStateVector = doc => {
-  const encoder = encoding.createEncoder()
-  writeDocumentStateVector(encoder, doc)
-  return encoding.toUint8Array(encoder)
+export const encodeStateVectorV2 = (doc, encoder = new DSEncoderV2()) => {
+  if (doc instanceof Map) {
+    writeStateVector(encoder, doc)
+  } else {
+    writeDocumentStateVector(encoder, doc)
+  }
+  return encoder.toUint8Array()
 }
+
+/**
+ * Encode State as Uint8Array.
+ *
+ * @param {Doc|Map<number,number>} doc
+ * @return {Uint8Array}
+ *
+ * @function
+ */
+export const encodeStateVector = doc => encodeStateVectorV2(doc, new DSEncoderV1())

src/utils/isParentOf.js

@@ -16,7 +16,7 @@ export const isParentOf = (parent, child) => {
     if (child.parent === parent) {
       return true
     }
-    child = child.parent._item
+    child = /** @type {AbstractType<any>} */ (child.parent)._item
   }
   return false
 }

src/utils/logging.js

@@ -0,0 +1,22 @@
+
+import {
+  AbstractType // eslint-disable-line
+} from '../internals.js'
+
+/**
+ * Convenient helper to log type information.
+ *
+ * Do not use in productive systems as the output can be immense!
+ *
+ * @param {AbstractType<any>} type
+ */
+export const logType = type => {
+  const res = []
+  let n = type._start
+  while (n) {
+    res.push(n)
+    n = n.right
+  }
+  console.log('Children: ', res)
+  console.log('Children content: ', res.filter(m => !m.deleted).map(m => m.content))
+}

src/utils/updates.js

@@ -0,0 +1,581 @@
+
+import * as binary from 'lib0/binary'
+import * as decoding from 'lib0/decoding'
+import * as encoding from 'lib0/encoding'
+import * as logging from 'lib0/logging'
+import * as math from 'lib0/math'
+import {
+  createID,
+  readItemContent,
+  readDeleteSet,
+  writeDeleteSet,
+  Skip,
+  mergeDeleteSets,
+  DSEncoderV1,
+  DSEncoderV2,
+  decodeStateVector,
+  Item, GC, UpdateDecoderV1, UpdateDecoderV2, UpdateEncoderV1, UpdateEncoderV2 // eslint-disable-line
+} from '../internals.js'
+
+/**
+ * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
+ */
+function * lazyStructReaderGenerator (decoder) {
+  const numOfStateUpdates = decoding.readVarUint(decoder.restDecoder)
+  for (let i = 0; i < numOfStateUpdates; i++) {
+    const numberOfStructs = decoding.readVarUint(decoder.restDecoder)
+    const client = decoder.readClient()
+    let clock = decoding.readVarUint(decoder.restDecoder)
+    for (let i = 0; i < numberOfStructs; i++) {
+      const info = decoder.readInfo()
+      // @todo use switch instead of ifs
+      if (info === 10) {
+        const len = decoding.readVarUint(decoder.restDecoder)
+        yield new Skip(createID(client, clock), len)
+        clock += len
+      } else if ((binary.BITS5 & info) !== 0) {
+        const cantCopyParentInfo = (info & (binary.BIT7 | binary.BIT8)) === 0
+        // If parent = null and neither left nor right are defined, then we know that `parent` is child of `y`
+        // and we read the next string as parentYKey.
+        // It indicates how we store/retrieve parent from `y.share`
+        // @type {string|null}
+        const struct = new Item(
+          createID(client, clock),
+          null, // left
+          (info & binary.BIT8) === binary.BIT8 ? decoder.readLeftID() : null, // origin
+          null, // right
+          (info & binary.BIT7) === binary.BIT7 ? decoder.readRightID() : null, // right origin
+          // @ts-ignore Force writing a string here.
+          cantCopyParentInfo ? (decoder.readParentInfo() ? decoder.readString() : decoder.readLeftID()) : null, // parent
+          cantCopyParentInfo && (info & binary.BIT6) === binary.BIT6 ? decoder.readString() : null, // parentSub
+          readItemContent(decoder, info) // item content
+        )
+        yield struct
+        clock += struct.length
+      } else {
+        const len = decoder.readLen()
+        yield new GC(createID(client, clock), len)
+        clock += len
+      }
+    }
+  }
+}
+
+export class LazyStructReader {
+  /**
+   * @param {UpdateDecoderV1 | UpdateDecoderV2} decoder
+   * @param {boolean} filterSkips
+   */
+  constructor (decoder, filterSkips) {
+    this.gen = lazyStructReaderGenerator(decoder)
+    /**
+     * @type {null | Item | Skip | GC}
+     */
+    this.curr = null
+    this.done = false
+    this.filterSkips = filterSkips
+    this.next()
+  }
+
+  /**
+   * @return {Item | GC | Skip |null}
+   */
+  next () {
+    // ignore "Skip" structs
+    do {
+      this.curr = this.gen.next().value || null
+    } while (this.filterSkips && this.curr !== null && this.curr.constructor === Skip)
+    return this.curr
+  }
+}
+
+/**
+ * @param {Uint8Array} update
+ *
+ */
+export const logUpdate = update => logUpdateV2(update, UpdateDecoderV1)
+
+/**
+ * @param {Uint8Array} update
+ * @param {typeof UpdateDecoderV2 | typeof UpdateDecoderV1} [YDecoder]
+ *
+ */
+export const logUpdateV2 = (update, YDecoder = UpdateDecoderV2) => {
+  const structs = []
+  const updateDecoder = new YDecoder(decoding.createDecoder(update))
+  const lazyDecoder = new LazyStructReader(updateDecoder, false)
+  for (let curr = lazyDecoder.curr; curr !== null; curr = lazyDecoder.next()) {
+    structs.push(curr)
+  }
+  logging.print('Structs: ', structs)
+  const ds = readDeleteSet(updateDecoder)
+  logging.print('DeleteSet: ', ds)
+}
+
+/**
+ * @param {Uint8Array} update
+ *
+ */
+export const decodeUpdate = (update) => decodeUpdateV2(update, UpdateDecoderV1)
+
+/**
+ * @param {Uint8Array} update
+ * @param {typeof UpdateDecoderV2 | typeof UpdateDecoderV1} [YDecoder]
+ *
+ */
+export const decodeUpdateV2 = (update, YDecoder = UpdateDecoderV2) => {
+  const structs = []
+  const updateDecoder = new YDecoder(decoding.createDecoder(update))
+  const lazyDecoder = new LazyStructReader(updateDecoder, false)
+  for (let curr = lazyDecoder.curr; curr !== null; curr = lazyDecoder.next()) {
+    structs.push(curr)
+  }
+  return {
+    structs,
+    ds: readDeleteSet(updateDecoder)
+  }
+}
+
+export class LazyStructWriter {
+  /**
+   * @param {UpdateEncoderV1 | UpdateEncoderV2} encoder
+   */
+  constructor (encoder) {
+    this.currClient = 0
+    this.startClock = 0
+    this.written = 0
+    this.encoder = encoder
+    /**
+     * We want to write operations lazily, but also we need to know beforehand how many operations we want to write for each client.
+     *
+     * This kind of meta-information (#clients, #structs-per-client-written) is written to the restEncoder.
+     *
+     * We fragment the restEncoder and store a slice of it per-client until we know how many clients there are.
+     * When we flush (toUint8Array) we write the restEncoder using the fragments and the meta-information.
+     *
+     * @type {Array<{ written: number, restEncoder: Uint8Array }>}
+     */
+    this.clientStructs = []
+  }
+}
+
+/**
+ * @param {Array<Uint8Array>} updates
+ * @return {Uint8Array}
+ */
+export const mergeUpdates = updates => mergeUpdatesV2(updates, UpdateDecoderV1, UpdateEncoderV1)
+
+/**
+ * @param {Uint8Array} update
+ * @param {typeof DSEncoderV1 | typeof DSEncoderV2} YEncoder
+ * @param {typeof UpdateDecoderV1 | typeof UpdateDecoderV2} YDecoder
+ * @return {Uint8Array}
+ */
+export const encodeStateVectorFromUpdateV2 = (update, YEncoder = DSEncoderV2, YDecoder = UpdateDecoderV2) => {
+  const encoder = new YEncoder()
+  const updateDecoder = new LazyStructReader(new YDecoder(decoding.createDecoder(update)), false)
+  let curr = updateDecoder.curr
+  if (curr !== null) {
+    let size = 0
+    let currClient = curr.id.client
+    let stopCounting = curr.id.clock !== 0 // must start at 0
+    let currClock = stopCounting ? 0 : curr.id.clock + curr.length
+    for (; curr !== null; curr = updateDecoder.next()) {
+      if (currClient !== curr.id.client) {
+        if (currClock !== 0) {
+          size++
+          // We found a new client
+          // write what we have to the encoder
+          encoding.writeVarUint(encoder.restEncoder, currClient)
+          encoding.writeVarUint(encoder.restEncoder, currClock)
+        }
+        currClient = curr.id.client
+        currClock = 0
+        stopCounting = curr.id.clock !== 0
+      }
+      // we ignore skips
+      if (curr.constructor === Skip) {
+        stopCounting = true
+      }
+      if (!stopCounting) {
+        currClock = curr.id.clock + curr.length
+      }
+    }
+    // write what we have
+    if (currClock !== 0) {
+      size++
+      encoding.writeVarUint(encoder.restEncoder, currClient)
+      encoding.writeVarUint(encoder.restEncoder, currClock)
+    }
+    // prepend the size of the state vector
+    const enc = encoding.createEncoder()
+    encoding.writeVarUint(enc, size)
+    encoding.writeBinaryEncoder(enc, encoder.restEncoder)
+    encoder.restEncoder = enc
+    return encoder.toUint8Array()
+  } else {
+    encoding.writeVarUint(encoder.restEncoder, 0)
+    return encoder.toUint8Array()
+  }
+}
+
+/**
+ * @param {Uint8Array} update
+ * @return {Uint8Array}
+ */
+export const encodeStateVectorFromUpdate = update => encodeStateVectorFromUpdateV2(update, DSEncoderV1, UpdateDecoderV1)
+
+/**
+ * @param {Uint8Array} update
+ * @param {typeof UpdateDecoderV1 | typeof UpdateDecoderV2} YDecoder
+ * @return {{ from: Map<number,number>, to: Map<number,number> }}
+ */
+export const parseUpdateMetaV2 = (update, YDecoder = UpdateDecoderV2) => {
+  /**
+   * @type {Map<number, number>}
+   */
+  const from = new Map()
+  /**
+   * @type {Map<number, number>}
+   */
+  const to = new Map()
+  const updateDecoder = new LazyStructReader(new YDecoder(decoding.createDecoder(update)), false)
+  let curr = updateDecoder.curr
+  if (curr !== null) {
+    let currClient = curr.id.client
+    let currClock = curr.id.clock
+    // write the beginning to `from`
+    from.set(currClient, currClock)
+    for (; curr !== null; curr = updateDecoder.next()) {
+      if (currClient !== curr.id.client) {
+        // We found a new client
+        // write the end to `to`
+        to.set(currClient, currClock)
+        // write the beginning to `from`
+        from.set(curr.id.client, curr.id.clock)
+        // update currClient
+        currClient = curr.id.client
+      }
+      currClock = curr.id.clock + curr.length
+    }
+    // write the end to `to`
+    to.set(currClient, currClock)
+  }
+  return { from, to }
+}
+
+/**
+ * @param {Uint8Array} update
+ * @return {{ from: Map<number,number>, to: Map<number,number> }}
+ */
+export const parseUpdateMeta = update => parseUpdateMetaV2(update, UpdateDecoderV1)
+
+/**
+ * This method is intended to slice any kind of struct and retrieve the right part.
+ * It does not handle side-effects, so it should only be used by the lazy-encoder.
+ *
+ * @param {Item | GC | Skip} left
+ * @param {number} diff
+ * @return {Item | GC}
+ */
+const sliceStruct = (left, diff) => {
+  if (left.constructor === GC) {
+    const { client, clock } = left.id
+    return new GC(createID(client, clock + diff), left.length - diff)
+  } else if (left.constructor === Skip) {
+    const { client, clock } = left.id
+    return new Skip(createID(client, clock + diff), left.length - diff)
+  } else {
+    const leftItem = /** @type {Item} */ (left)
+    const { client, clock } = leftItem.id
+    return new Item(
+      createID(client, clock + diff),
+      null,
+      createID(client, clock + diff - 1),
+      null,
+      leftItem.rightOrigin,
+      leftItem.parent,
+      leftItem.parentSub,
+      leftItem.content.splice(diff)
+    )
+  }
+}
+
+/**
+ *
+ * This function works similarly to `readUpdateV2`.
+ *
+ * @param {Array<Uint8Array>} updates
+ * @param {typeof UpdateDecoderV1 | typeof UpdateDecoderV2} [YDecoder]
+ * @param {typeof UpdateEncoderV1 | typeof UpdateEncoderV2} [YEncoder]
+ * @return {Uint8Array}
+ */
+export const mergeUpdatesV2 = (updates, YDecoder = UpdateDecoderV2, YEncoder = UpdateEncoderV2) => {
+  if (updates.length === 1) {
+    return updates[0]
+  }
+  const updateDecoders = updates.map(update => new YDecoder(decoding.createDecoder(update)))
+  let lazyStructDecoders = updateDecoders.map(decoder => new LazyStructReader(decoder, true))
+
+  /**
+   * @todo we don't need offset because we always slice before
+   * @type {null | { struct: Item | GC | Skip, offset: number }}
+   */
+  let currWrite = null
+
+  const updateEncoder = new YEncoder()
+  // write structs lazily
+  const lazyStructEncoder = new LazyStructWriter(updateEncoder)
+
+  // Note: We need to ensure that all lazyStructDecoders are fully consumed
+  // Note: Should merge document updates whenever possible - even from different updates
+  // Note: Should handle that some operations cannot be applied yet ()
+
+  while (true) {
+    // Write higher clients first ⇒ sort by clientID & clock and remove decoders without content
+    lazyStructDecoders = lazyStructDecoders.filter(dec => dec.curr !== null)
+    lazyStructDecoders.sort(
+      /** @type {function(any,any):number} */ (dec1, dec2) => {
+        if (dec1.curr.id.client === dec2.curr.id.client) {
+          const clockDiff = dec1.curr.id.clock - dec2.curr.id.clock
+          if (clockDiff === 0) {
+            // @todo remove references to skip since the structDecoders must filter Skips.
+            return dec1.curr.constructor === dec2.curr.constructor
+              ? 0
+              : dec1.curr.constructor === Skip ? 1 : -1 // we are filtering skips anyway.
+          } else {
+            return clockDiff
+          }
+        } else {
+          return dec2.curr.id.client - dec1.curr.id.client
+        }
+      }
+    )
+    if (lazyStructDecoders.length === 0) {
+      break
+    }
+    const currDecoder = lazyStructDecoders[0]
+    // write from currDecoder until the next operation is from another client or if filler-struct
+    // then we need to reorder the decoders and find the next operation to write
+    const firstClient = /** @type {Item | GC} */ (currDecoder.curr).id.client
+
+    if (currWrite !== null) {
+      let curr = /** @type {Item | GC | null} */ (currDecoder.curr)
+      let iterated = false
+
+      // iterate until we find something that we haven't written already
+      // remember: first the high client-ids are written
+      while (curr !== null && curr.id.clock + curr.length <= currWrite.struct.id.clock + currWrite.struct.length && curr.id.client >= currWrite.struct.id.client) {
+        curr = currDecoder.next()
+        iterated = true
+      }
+      if (
+        curr === null || // current decoder is empty
+        curr.id.client !== firstClient || // check whether there is another decoder that has has updates from `firstClient`
+        (iterated && curr.id.clock > currWrite.struct.id.clock + currWrite.struct.length) // the above while loop was used and we are potentially missing updates
+      ) {
+        continue
+      }
+
+      if (firstClient !== currWrite.struct.id.client) {
+        writeStructToLazyStructWriter(lazyStructEncoder, currWrite.struct, currWrite.offset)
+        currWrite = { struct: curr, offset: 0 }
+        currDecoder.next()
+      } else {
+        if (currWrite.struct.id.clock + currWrite.struct.length < curr.id.clock) {
+          // @todo write currStruct & set currStruct = Skip(clock = currStruct.id.clock + currStruct.length, length = curr.id.clock - self.clock)
+          if (currWrite.struct.constructor === Skip) {
+            // extend existing skip
+            currWrite.struct.length = curr.id.clock + curr.length - currWrite.struct.id.clock
+          } else {
+            writeStructToLazyStructWriter(lazyStructEncoder, currWrite.struct, currWrite.offset)
+            const diff = curr.id.clock - currWrite.struct.id.clock - currWrite.struct.length
+            /**
+             * @type {Skip}
+             */
+            const struct = new Skip(createID(firstClient, currWrite.struct.id.clock + currWrite.struct.length), diff)
+            currWrite = { struct, offset: 0 }
+          }
+        } else { // if (currWrite.struct.id.clock + currWrite.struct.length >= curr.id.clock) {
+          const diff = currWrite.struct.id.clock + currWrite.struct.length - curr.id.clock
+          if (diff > 0) {
+            if (currWrite.struct.constructor === Skip) {
+              // prefer to slice Skip because the other struct might contain more information
+              currWrite.struct.length -= diff
+            } else {
+              curr = sliceStruct(curr, diff)
+            }
+          }
+          if (!currWrite.struct.mergeWith(/** @type {any} */ (curr))) {
+            writeStructToLazyStructWriter(lazyStructEncoder, currWrite.struct, currWrite.offset)
+            currWrite = { struct: curr, offset: 0 }
+            currDecoder.next()
+          }
+        }
+      }
+    } else {
+      currWrite = { struct: /** @type {Item | GC} */ (currDecoder.curr), offset: 0 }
+      currDecoder.next()
+    }
+    for (
+      let next = currDecoder.curr;
+      next !== null && next.id.client === firstClient && next.id.clock === currWrite.struct.id.clock + currWrite.struct.length && next.constructor !== Skip;
+      next = currDecoder.next()
+    ) {
+      writeStructToLazyStructWriter(lazyStructEncoder, currWrite.struct, currWrite.offset)
+      currWrite = { struct: next, offset: 0 }
+    }
+  }
+  if (currWrite !== null) {
+    writeStructToLazyStructWriter(lazyStructEncoder, currWrite.struct, currWrite.offset)
+    currWrite = null
+  }
+  finishLazyStructWriting(lazyStructEncoder)
+
+  const dss = updateDecoders.map(decoder => readDeleteSet(decoder))
+  const ds = mergeDeleteSets(dss)
+  writeDeleteSet(updateEncoder, ds)
+  return updateEncoder.toUint8Array()
+}
+
+/**
+ * @param {Uint8Array} update
+ * @param {Uint8Array} sv
+ * @param {typeof UpdateDecoderV1 | typeof UpdateDecoderV2} [YDecoder]
+ * @param {typeof UpdateEncoderV1 | typeof UpdateEncoderV2} [YEncoder]
+ */
+export const diffUpdateV2 = (update, sv, YDecoder = UpdateDecoderV2, YEncoder = UpdateEncoderV2) => {
+  const state = decodeStateVector(sv)
+  const encoder = new YEncoder()
+  const lazyStructWriter = new LazyStructWriter(encoder)
+  const decoder = new YDecoder(decoding.createDecoder(update))
+  const reader = new LazyStructReader(decoder, false)
+  while (reader.curr) {
+    const curr = reader.curr
+    const currClient = curr.id.client
+    const svClock = state.get(currClient) || 0
+    if (reader.curr.constructor === Skip) {
+      // the first written struct shouldn't be a skip
+      reader.next()
+      continue
+    }
+    if (curr.id.clock + curr.length > svClock) {
+      writeStructToLazyStructWriter(lazyStructWriter, curr, math.max(svClock - curr.id.clock, 0))
+      reader.next()
+      while (reader.curr && reader.curr.id.client === currClient) {
+        writeStructToLazyStructWriter(lazyStructWriter, reader.curr, 0)
+        reader.next()
+      }
+    } else {
+      // read until something new comes up
+      while (reader.curr && reader.curr.id.client === currClient && reader.curr.id.clock + reader.curr.length <= svClock) {
+        reader.next()
+      }
+    }
+  }
+  finishLazyStructWriting(lazyStructWriter)
+  // write ds
+  const ds = readDeleteSet(decoder)
+  writeDeleteSet(encoder, ds)
+  return encoder.toUint8Array()
+}
+
+/**
+ * @param {Uint8Array} update
+ * @param {Uint8Array} sv
+ */
+export const diffUpdate = (update, sv) => diffUpdateV2(update, sv, UpdateDecoderV1, UpdateEncoderV1)
+
+/**
+ * @param {LazyStructWriter} lazyWriter
+ */
+const flushLazyStructWriter = lazyWriter => {
+  if (lazyWriter.written > 0) {
+    lazyWriter.clientStructs.push({ written: lazyWriter.written, restEncoder: encoding.toUint8Array(lazyWriter.encoder.restEncoder) })
+    lazyWriter.encoder.restEncoder = encoding.createEncoder()
+    lazyWriter.written = 0
+  }
+}
+
+/**
+ * @param {LazyStructWriter} lazyWriter
+ * @param {Item | GC} struct
+ * @param {number} offset
+ */
+const writeStructToLazyStructWriter = (lazyWriter, struct, offset) => {
+  // flush curr if we start another client
+  if (lazyWriter.written > 0 && lazyWriter.currClient !== struct.id.client) {
+    flushLazyStructWriter(lazyWriter)
+  }
+  if (lazyWriter.written === 0) {
+    lazyWriter.currClient = struct.id.client
+    // write next client
+    lazyWriter.encoder.writeClient(struct.id.client)
+    // write startClock
+    encoding.writeVarUint(lazyWriter.encoder.restEncoder, struct.id.clock + offset)
+  }
+  struct.write(lazyWriter.encoder, offset)
+  lazyWriter.written++
+}
+/**
+ * Call this function when we collected all parts and want to
+ * put all the parts together. After calling this method,
+ * you can continue using the UpdateEncoder.
+ *
+ * @param {LazyStructWriter} lazyWriter
+ */
+const finishLazyStructWriting = (lazyWriter) => {
+  flushLazyStructWriter(lazyWriter)
+
+  // this is a fresh encoder because we called flushCurr
+  const restEncoder = lazyWriter.encoder.restEncoder
+
+  /**
+   * Now we put all the fragments together.
+   * This works similarly to `writeClientsStructs`
+   */
+
+  // write # states that were updated - i.e. the clients
+  encoding.writeVarUint(restEncoder, lazyWriter.clientStructs.length)
+
+  for (let i = 0; i < lazyWriter.clientStructs.length; i++) {
+    const partStructs = lazyWriter.clientStructs[i]
+    /**
+     * Works similarly to `writeStructs`
+     */
+    // write # encoded structs
+    encoding.writeVarUint(restEncoder, partStructs.written)
+    // write the rest of the fragment
+    encoding.writeUint8Array(restEncoder, partStructs.restEncoder)
+  }
+}
+
+/**
+ * @param {Uint8Array} update
+ * @param {typeof UpdateDecoderV2 | typeof UpdateDecoderV1} YDecoder
+ * @param {typeof UpdateEncoderV2 | typeof UpdateEncoderV1 } YEncoder
+ */
+export const convertUpdateFormat = (update, YDecoder, YEncoder) => {
+  const updateDecoder = new YDecoder(decoding.createDecoder(update))
+  const lazyDecoder = new LazyStructReader(updateDecoder, false)
+  const updateEncoder = new YEncoder()
+  const lazyWriter = new LazyStructWriter(updateEncoder)
+
+  for (let curr = lazyDecoder.curr; curr !== null; curr = lazyDecoder.next()) {
+    writeStructToLazyStructWriter(lazyWriter, curr, 0)
+  }
+  finishLazyStructWriting(lazyWriter)
+  const ds = readDeleteSet(updateDecoder)
+  writeDeleteSet(updateEncoder, ds)
+  return updateEncoder.toUint8Array()
+}
+
+/**
+ * @param {Uint8Array} update
+ */
+export const convertUpdateFormatV1ToV2 = update => convertUpdateFormat(update, UpdateDecoderV1, UpdateEncoderV2)
+
+/**
+ * @param {Uint8Array} update
+ */
+export const convertUpdateFormatV2ToV1 = update => convertUpdateFormat(update, UpdateDecoderV2, UpdateEncoderV1)

tests/consistency.tests.js

@@ -1,19 +0,0 @@
-
-import * as Y from '../src/index.js'
-import * as t from 'lib0/testing.js'
-
-/**
- * Client id should be changed when an instance receives updates from another client using the same client id.
- *
- * @param {t.TestCase} tc
- */
-export const testClientIdDuplicateChange = tc => {
-  const doc1 = new Y.Doc()
-  doc1.clientID = 0
-  const doc2 = new Y.Doc()
-  doc2.clientID = 0
-  t.assert(doc2.clientID === doc1.clientID)
-  doc1.getArray('a').insert(0, [1, 2])
-  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc1))
-  t.assert(doc2.clientID !== doc1.clientID)
-}

tests/doc.tests.js

@@ -0,0 +1,312 @@
+
+import * as Y from '../src/index.js'
+import * as t from 'lib0/testing'
+
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testOriginInTransaction = _tc => {
+  const doc = new Y.Doc()
+  const ytext = doc.getText()
+  /**
+   * @type {Array<string>}
+   */
+  const origins = []
+  doc.on('afterTransaction', (tr) => {
+    origins.push(tr.origin)
+    if (origins.length <= 1) {
+      ytext.toDelta()
+      doc.transact(() => {
+        ytext.insert(0, 'a')
+      }, 'nested')
+    }
+  })
+  doc.transact(() => {
+    ytext.insert(0, '0')
+  }, 'first')
+  t.compareArrays(origins, ['first', 'cleanup', 'nested'])
+}
+
+/**
+ * Client id should be changed when an instance receives updates from another client using the same client id.
+ *
+ * @param {t.TestCase} _tc
+ */
+export const testClientIdDuplicateChange = _tc => {
+  const doc1 = new Y.Doc()
+  doc1.clientID = 0
+  const doc2 = new Y.Doc()
+  doc2.clientID = 0
+  t.assert(doc2.clientID === doc1.clientID)
+  doc1.getArray('a').insert(0, [1, 2])
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc1))
+  t.assert(doc2.clientID !== doc1.clientID)
+}
+
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testGetTypeEmptyId = _tc => {
+  const doc1 = new Y.Doc()
+  doc1.getText('').insert(0, 'h')
+  doc1.getText().insert(1, 'i')
+  const doc2 = new Y.Doc()
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc1))
+  t.assert(doc2.getText().toString() === 'hi')
+  t.assert(doc2.getText('').toString() === 'hi')
+}
+
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testToJSON = _tc => {
+  const doc = new Y.Doc()
+  t.compare(doc.toJSON(), {}, 'doc.toJSON yields empty object')
+
+  const arr = doc.getArray('array')
+  arr.push(['test1'])
+
+  const map = doc.getMap('map')
+  map.set('k1', 'v1')
+  const map2 = new Y.Map()
+  map.set('k2', map2)
+  map2.set('m2k1', 'm2v1')
+
+  t.compare(doc.toJSON(), {
+    array: ['test1'],
+    map: {
+      k1: 'v1',
+      k2: {
+        m2k1: 'm2v1'
+      }
+    }
+  }, 'doc.toJSON has array and recursive map')
+}
+
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testSubdoc = _tc => {
+  const doc = new Y.Doc()
+  doc.load() // doesn't do anything
+  {
+    /**
+     * @type {Array<any>|null}
+     */
+    let event = /** @type {any} */ (null)
+    doc.on('subdocs', subdocs => {
+      event = [Array.from(subdocs.added).map(x => x.guid), Array.from(subdocs.removed).map(x => x.guid), Array.from(subdocs.loaded).map(x => x.guid)]
+    })
+    const subdocs = doc.getMap('mysubdocs')
+    const docA = new Y.Doc({ guid: 'a' })
+    docA.load()
+    subdocs.set('a', docA)
+    t.compare(event, [['a'], [], ['a']])
+
+    event = null
+    subdocs.get('a').load()
+    t.assert(event === null)
+
+    event = null
+    subdocs.get('a').destroy()
+    t.compare(event, [['a'], ['a'], []])
+    subdocs.get('a').load()
+    t.compare(event, [[], [], ['a']])
+
+    subdocs.set('b', new Y.Doc({ guid: 'a', shouldLoad: false }))
+    t.compare(event, [['a'], [], []])
+    subdocs.get('b').load()
+    t.compare(event, [[], [], ['a']])
+
+    const docC = new Y.Doc({ guid: 'c' })
+    docC.load()
+    subdocs.set('c', docC)
+    t.compare(event, [['c'], [], ['c']])
+
+    t.compare(Array.from(doc.getSubdocGuids()), ['a', 'c'])
+  }
+
+  const doc2 = new Y.Doc()
+  {
+    t.compare(Array.from(doc2.getSubdocs()), [])
+    /**
+     * @type {Array<any>|null}
+     */
+    let event = /** @type {any} */ (null)
+    doc2.on('subdocs', subdocs => {
+      event = [Array.from(subdocs.added).map(d => d.guid), Array.from(subdocs.removed).map(d => d.guid), Array.from(subdocs.loaded).map(d => d.guid)]
+    })
+    Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+    t.compare(event, [['a', 'a', 'c'], [], []])
+
+    doc2.getMap('mysubdocs').get('a').load()
+    t.compare(event, [[], [], ['a']])
+
+    t.compare(Array.from(doc2.getSubdocGuids()), ['a', 'c'])
+
+    doc2.getMap('mysubdocs').delete('a')
+    t.compare(event, [[], ['a'], []])
+    t.compare(Array.from(doc2.getSubdocGuids()), ['a', 'c'])
+  }
+}
+
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testSubdocLoadEdgeCases = _tc => {
+  const ydoc = new Y.Doc()
+  const yarray = ydoc.getArray()
+  const subdoc1 = new Y.Doc()
+  /**
+   * @type {any}
+   */
+  let lastEvent = null
+  ydoc.on('subdocs', event => {
+    lastEvent = event
+  })
+  yarray.insert(0, [subdoc1])
+  t.assert(subdoc1.shouldLoad)
+  t.assert(subdoc1.autoLoad === false)
+  t.assert(lastEvent !== null && lastEvent.loaded.has(subdoc1))
+  t.assert(lastEvent !== null && lastEvent.added.has(subdoc1))
+  // destroy and check whether lastEvent adds it again to added (it shouldn't)
+  subdoc1.destroy()
+  const subdoc2 = yarray.get(0)
+  t.assert(subdoc1 !== subdoc2)
+  t.assert(lastEvent !== null && lastEvent.added.has(subdoc2))
+  t.assert(lastEvent !== null && !lastEvent.loaded.has(subdoc2))
+  // load
+  subdoc2.load()
+  t.assert(lastEvent !== null && !lastEvent.added.has(subdoc2))
+  t.assert(lastEvent !== null && lastEvent.loaded.has(subdoc2))
+  // apply from remote
+  const ydoc2 = new Y.Doc()
+  ydoc2.on('subdocs', event => {
+    lastEvent = event
+  })
+  Y.applyUpdate(ydoc2, Y.encodeStateAsUpdate(ydoc))
+  const subdoc3 = ydoc2.getArray().get(0)
+  t.assert(subdoc3.shouldLoad === false)
+  t.assert(subdoc3.autoLoad === false)
+  t.assert(lastEvent !== null && lastEvent.added.has(subdoc3))
+  t.assert(lastEvent !== null && !lastEvent.loaded.has(subdoc3))
+  // load
+  subdoc3.load()
+  t.assert(subdoc3.shouldLoad)
+  t.assert(lastEvent !== null && !lastEvent.added.has(subdoc3))
+  t.assert(lastEvent !== null && lastEvent.loaded.has(subdoc3))
+}
+
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testSubdocLoadEdgeCasesAutoload = _tc => {
+  const ydoc = new Y.Doc()
+  const yarray = ydoc.getArray()
+  const subdoc1 = new Y.Doc({ autoLoad: true })
+  /**
+   * @type {any}
+   */
+  let lastEvent = null
+  ydoc.on('subdocs', event => {
+    lastEvent = event
+  })
+  yarray.insert(0, [subdoc1])
+  t.assert(subdoc1.shouldLoad)
+  t.assert(subdoc1.autoLoad)
+  t.assert(lastEvent !== null && lastEvent.loaded.has(subdoc1))
+  t.assert(lastEvent !== null && lastEvent.added.has(subdoc1))
+  // destroy and check whether lastEvent adds it again to added (it shouldn't)
+  subdoc1.destroy()
+  const subdoc2 = yarray.get(0)
+  t.assert(subdoc1 !== subdoc2)
+  t.assert(lastEvent !== null && lastEvent.added.has(subdoc2))
+  t.assert(lastEvent !== null && !lastEvent.loaded.has(subdoc2))
+  // load
+  subdoc2.load()
+  t.assert(lastEvent !== null && !lastEvent.added.has(subdoc2))
+  t.assert(lastEvent !== null && lastEvent.loaded.has(subdoc2))
+  // apply from remote
+  const ydoc2 = new Y.Doc()
+  ydoc2.on('subdocs', event => {
+    lastEvent = event
+  })
+  Y.applyUpdate(ydoc2, Y.encodeStateAsUpdate(ydoc))
+  const subdoc3 = ydoc2.getArray().get(0)
+  t.assert(subdoc1.shouldLoad)
+  t.assert(subdoc1.autoLoad)
+  t.assert(lastEvent !== null && lastEvent.added.has(subdoc3))
+  t.assert(lastEvent !== null && lastEvent.loaded.has(subdoc3))
+}
+
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testSubdocsUndo = _tc => {
+  const ydoc = new Y.Doc()
+  const elems = ydoc.getXmlFragment()
+  const undoManager = new Y.UndoManager(elems)
+  const subdoc = new Y.Doc()
+  // @ts-ignore
+  elems.insert(0, [subdoc])
+  undoManager.undo()
+  undoManager.redo()
+  t.assert(elems.length === 1)
+}
+
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testLoadDocsEvent = async _tc => {
+  const ydoc = new Y.Doc()
+  t.assert(ydoc.isLoaded === false)
+  let loadedEvent = false
+  ydoc.on('load', () => {
+    loadedEvent = true
+  })
+  ydoc.emit('load', [ydoc])
+  await ydoc.whenLoaded
+  t.assert(loadedEvent)
+  t.assert(ydoc.isLoaded)
+}
+
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testSyncDocsEvent = async _tc => {
+  const ydoc = new Y.Doc()
+  t.assert(ydoc.isLoaded === false)
+  t.assert(ydoc.isSynced === false)
+  let loadedEvent = false
+  ydoc.once('load', () => {
+    loadedEvent = true
+  })
+  let syncedEvent = false
+  ydoc.once('sync', /** @param {any} isSynced */ (isSynced) => {
+    syncedEvent = true
+    t.assert(isSynced)
+  })
+  ydoc.emit('sync', [true, ydoc])
+  await ydoc.whenLoaded
+  const oldWhenSynced = ydoc.whenSynced
+  await ydoc.whenSynced
+  t.assert(loadedEvent)
+  t.assert(syncedEvent)
+  t.assert(ydoc.isLoaded)
+  t.assert(ydoc.isSynced)
+  let loadedEvent2 = false
+  ydoc.on('load', () => {
+    loadedEvent2 = true
+  })
+  let syncedEvent2 = false
+  ydoc.on('sync', (isSynced) => {
+    syncedEvent2 = true
+    t.assert(isSynced === false)
+  })
+  ydoc.emit('sync', [false, ydoc])
+  t.assert(!loadedEvent2)
+  t.assert(syncedEvent2)
+  t.assert(ydoc.isLoaded)
+  t.assert(!ydoc.isSynced)
+  t.assert(ydoc.whenSynced !== oldWhenSynced)
+}

tests/encoding.tests.js

@@ -1,4 +1,5 @@
-import * as t from 'lib0/testing.js'
+import * as t from 'lib0/testing'
+import * as promise from 'lib0/promise'
 
 import {
   contentRefs,
@@ -9,14 +10,21 @@ import {
   readContentEmbed,
   readContentType,
   readContentFormat,
-  readContentAny
+  readContentAny,
+  readContentDoc,
+  Doc,
+  PermanentUserData,
+  encodeStateAsUpdate,
+  applyUpdate
 } from '../src/internals.js'
 
+import * as Y from '../src/index.js'
+
 /**
  * @param {t.TestCase} tc
  */
 export const testStructReferences = tc => {
-  t.assert(contentRefs.length === 9)
+  t.assert(contentRefs.length === 11)
   t.assert(contentRefs[1] === readContentDeleted)
   t.assert(contentRefs[2] === readContentJSON) // TODO: deprecate content json?
   t.assert(contentRefs[3] === readContentBinary)
@@ -25,4 +33,76 @@ export const testStructReferences = tc => {
   t.assert(contentRefs[6] === readContentFormat)
   t.assert(contentRefs[7] === readContentType)
   t.assert(contentRefs[8] === readContentAny)
+  t.assert(contentRefs[9] === readContentDoc)
+  // contentRefs[10] is reserved for Skip structs
+}
+
+/**
+ * There is some custom encoding/decoding happening in PermanentUserData.
+ * This is why it landed here.
+ *
+ * @param {t.TestCase} tc
+ */
+export const testPermanentUserData = async tc => {
+  const ydoc1 = new Doc()
+  const ydoc2 = new Doc()
+  const pd1 = new PermanentUserData(ydoc1)
+  const pd2 = new PermanentUserData(ydoc2)
+  pd1.setUserMapping(ydoc1, ydoc1.clientID, 'user a')
+  pd2.setUserMapping(ydoc2, ydoc2.clientID, 'user b')
+  ydoc1.getText().insert(0, 'xhi')
+  ydoc1.getText().delete(0, 1)
+  ydoc2.getText().insert(0, 'hxxi')
+  ydoc2.getText().delete(1, 2)
+  await promise.wait(10)
+  applyUpdate(ydoc2, encodeStateAsUpdate(ydoc1))
+  applyUpdate(ydoc1, encodeStateAsUpdate(ydoc2))
+
+  // now sync a third doc with same name as doc1 and then create PermanentUserData
+  const ydoc3 = new Doc()
+  applyUpdate(ydoc3, encodeStateAsUpdate(ydoc1))
+  const pd3 = new PermanentUserData(ydoc3)
+  pd3.setUserMapping(ydoc3, ydoc3.clientID, 'user a')
+}
+
+/**
+ * Reported here: https://github.com/yjs/yjs/issues/308
+ * @param {t.TestCase} tc
+ */
+export const testDiffStateVectorOfUpdateIsEmpty = tc => {
+  const ydoc = new Y.Doc()
+  /**
+   * @type {any}
+   */
+  let sv = null
+  ydoc.getText().insert(0, 'a')
+  ydoc.on('update', update => {
+    sv = Y.encodeStateVectorFromUpdate(update)
+  })
+  // should produce an update with an empty state vector (because previous ops are missing)
+  ydoc.getText().insert(0, 'a')
+  t.assert(sv !== null && sv.byteLength === 1 && sv[0] === 0)
+}
+
+/**
+ * Reported here: https://github.com/yjs/yjs/issues/308
+ * @param {t.TestCase} tc
+ */
+export const testDiffStateVectorOfUpdateIgnoresSkips = tc => {
+  const ydoc = new Y.Doc()
+  /**
+   * @type {Array<Uint8Array>}
+   */
+  const updates = []
+  ydoc.on('update', update => {
+    updates.push(update)
+  })
+  ydoc.getText().insert(0, 'a')
+  ydoc.getText().insert(0, 'b')
+  ydoc.getText().insert(0, 'c')
+  const update13 = Y.mergeUpdates([updates[0], updates[2]])
+  const sv = Y.encodeStateVectorFromUpdate(update13)
+  const state = Y.decodeStateVector(sv)
+  t.assert(state.get(ydoc.clientID) === 1)
+  t.assert(state.size === 1)
 }

tests/index.js

@@ -1,21 +1,25 @@
 
-import * as array from './y-array.tests.js'
 import * as map from './y-map.tests.js'
+import * as array from './y-array.tests.js'
 import * as text from './y-text.tests.js'
 import * as xml from './y-xml.tests.js'
 import * as encoding from './encoding.tests.js'
 import * as undoredo from './undo-redo.tests.js'
-import * as consistency from './consistency.tests.js'
+import * as compatibility from './compatibility.tests.js'
+import * as doc from './doc.tests.js'
+import * as snapshot from './snapshot.tests.js'
+import * as updates from './updates.tests.js'
+import * as relativePositions from './relativePositions.tests.js'
 
-import { runTests } from 'lib0/testing.js'
-import { isBrowser, isNode } from 'lib0/environment.js'
-import * as log from 'lib0/logging.js'
+import { runTests } from 'lib0/testing'
+import { isBrowser, isNode } from 'lib0/environment'
+import * as log from 'lib0/logging'
 
 if (isBrowser) {
   log.createVConsole(document.body)
 }
 runTests({
-  map, array, text, xml, consistency, encoding, undoredo
+  doc, map, array, text, xml, encoding, undoredo, compatibility, snapshot, updates, relativePositions
 }).then(success => {
   /* istanbul ignore next */
   if (isNode) {

tests/relativePositions.tests.js

@@ -0,0 +1,104 @@
+
+import * as Y from '../src/index.js'
+import * as t from 'lib0/testing'
+
+/**
+ * @param {Y.Text} ytext
+ */
+const checkRelativePositions = ytext => {
+  // test if all positions are encoded and restored correctly
+  for (let i = 0; i < ytext.length; i++) {
+    // for all types of associations..
+    for (let assoc = -1; assoc < 2; assoc++) {
+      const rpos = Y.createRelativePositionFromTypeIndex(ytext, i, assoc)
+      const encodedRpos = Y.encodeRelativePosition(rpos)
+      const decodedRpos = Y.decodeRelativePosition(encodedRpos)
+      const absPos = /** @type {Y.AbsolutePosition} */ (Y.createAbsolutePositionFromRelativePosition(decodedRpos, /** @type {Y.Doc} */ (ytext.doc)))
+      t.assert(absPos.index === i)
+      t.assert(absPos.assoc === assoc)
+    }
+  }
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRelativePositionCase1 = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = ydoc.getText()
+  ytext.insert(0, '1')
+  ytext.insert(0, 'abc')
+  ytext.insert(0, 'z')
+  ytext.insert(0, 'y')
+  ytext.insert(0, 'x')
+  checkRelativePositions(ytext)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRelativePositionCase2 = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = ydoc.getText()
+  ytext.insert(0, 'abc')
+  checkRelativePositions(ytext)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRelativePositionCase3 = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = ydoc.getText()
+  ytext.insert(0, 'abc')
+  ytext.insert(0, '1')
+  ytext.insert(0, 'xyz')
+  checkRelativePositions(ytext)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRelativePositionCase4 = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = ydoc.getText()
+  ytext.insert(0, '1')
+  checkRelativePositions(ytext)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRelativePositionCase5 = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = ydoc.getText()
+  ytext.insert(0, '2')
+  ytext.insert(0, '1')
+  checkRelativePositions(ytext)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRelativePositionCase6 = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = ydoc.getText()
+  checkRelativePositions(ytext)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRelativePositionAssociationDifference = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = ydoc.getText()
+  ytext.insert(0, '2')
+  ytext.insert(0, '1')
+  const rposRight = Y.createRelativePositionFromTypeIndex(ytext, 1, 0)
+  const rposLeft = Y.createRelativePositionFromTypeIndex(ytext, 1, -1)
+  ytext.insert(1, 'x')
+  const posRight = Y.createAbsolutePositionFromRelativePosition(rposRight, ydoc)
+  const posLeft = Y.createAbsolutePositionFromRelativePosition(rposLeft, ydoc)
+  t.assert(posRight != null && posRight.index === 2)
+  t.assert(posLeft != null && posLeft.index === 1)
+}

tests/snapshot.tests.js

@@ -0,0 +1,171 @@
+import * as Y from '../src/index.js'
+import * as t from 'lib0/testing'
+import { init } from './testHelper.js'
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testBasicRestoreSnapshot = tc => {
+  const doc = new Y.Doc({ gc: false })
+  doc.getArray('array').insert(0, ['hello'])
+  const snap = Y.snapshot(doc)
+  doc.getArray('array').insert(1, ['world'])
+
+  const docRestored = Y.createDocFromSnapshot(doc, snap)
+
+  t.compare(docRestored.getArray('array').toArray(), ['hello'])
+  t.compare(doc.getArray('array').toArray(), ['hello', 'world'])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testEmptyRestoreSnapshot = tc => {
+  const doc = new Y.Doc({ gc: false })
+  const snap = Y.snapshot(doc)
+  snap.sv.set(9999, 0)
+  doc.getArray().insert(0, ['world'])
+
+  const docRestored = Y.createDocFromSnapshot(doc, snap)
+
+  t.compare(docRestored.getArray().toArray(), [])
+  t.compare(doc.getArray().toArray(), ['world'])
+
+  // now this snapshot reflects the latest state. It shoult still work.
+  const snap2 = Y.snapshot(doc)
+  const docRestored2 = Y.createDocFromSnapshot(doc, snap2)
+  t.compare(docRestored2.getArray().toArray(), ['world'])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRestoreSnapshotWithSubType = tc => {
+  const doc = new Y.Doc({ gc: false })
+  doc.getArray('array').insert(0, [new Y.Map()])
+  const subMap = doc.getArray('array').get(0)
+  subMap.set('key1', 'value1')
+
+  const snap = Y.snapshot(doc)
+  subMap.set('key2', 'value2')
+
+  const docRestored = Y.createDocFromSnapshot(doc, snap)
+
+  t.compare(docRestored.getArray('array').toJSON(), [{
+    key1: 'value1'
+  }])
+  t.compare(doc.getArray('array').toJSON(), [{
+    key1: 'value1',
+    key2: 'value2'
+  }])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRestoreDeletedItem1 = tc => {
+  const doc = new Y.Doc({ gc: false })
+  doc.getArray('array').insert(0, ['item1', 'item2'])
+
+  const snap = Y.snapshot(doc)
+  doc.getArray('array').delete(0)
+
+  const docRestored = Y.createDocFromSnapshot(doc, snap)
+
+  t.compare(docRestored.getArray('array').toArray(), ['item1', 'item2'])
+  t.compare(doc.getArray('array').toArray(), ['item2'])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRestoreLeftItem = tc => {
+  const doc = new Y.Doc({ gc: false })
+  doc.getArray('array').insert(0, ['item1'])
+  doc.getMap('map').set('test', 1)
+  doc.getArray('array').insert(0, ['item0'])
+
+  const snap = Y.snapshot(doc)
+  doc.getArray('array').delete(1)
+
+  const docRestored = Y.createDocFromSnapshot(doc, snap)
+
+  t.compare(docRestored.getArray('array').toArray(), ['item0', 'item1'])
+  t.compare(doc.getArray('array').toArray(), ['item0'])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testDeletedItemsBase = tc => {
+  const doc = new Y.Doc({ gc: false })
+  doc.getArray('array').insert(0, ['item1'])
+  doc.getArray('array').delete(0)
+  const snap = Y.snapshot(doc)
+  doc.getArray('array').insert(0, ['item0'])
+
+  const docRestored = Y.createDocFromSnapshot(doc, snap)
+
+  t.compare(docRestored.getArray('array').toArray(), [])
+  t.compare(doc.getArray('array').toArray(), ['item0'])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testDeletedItems2 = tc => {
+  const doc = new Y.Doc({ gc: false })
+  doc.getArray('array').insert(0, ['item1', 'item2', 'item3'])
+  doc.getArray('array').delete(1)
+  const snap = Y.snapshot(doc)
+  doc.getArray('array').insert(0, ['item0'])
+
+  const docRestored = Y.createDocFromSnapshot(doc, snap)
+
+  t.compare(docRestored.getArray('array').toArray(), ['item1', 'item3'])
+  t.compare(doc.getArray('array').toArray(), ['item0', 'item1', 'item3'])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testDependentChanges = tc => {
+  const { array0, array1, testConnector } = init(tc, { users: 2 })
+
+  if (!array0.doc) {
+    throw new Error('no document 0')
+  }
+  if (!array1.doc) {
+    throw new Error('no document 1')
+  }
+
+  /**
+   * @type {Y.Doc}
+   */
+  const doc0 = array0.doc
+  /**
+   * @type {Y.Doc}
+   */
+  const doc1 = array1.doc
+
+  doc0.gc = false
+  doc1.gc = false
+
+  array0.insert(0, ['user1item1'])
+  testConnector.syncAll()
+  array1.insert(1, ['user2item1'])
+  testConnector.syncAll()
+
+  const snap = Y.snapshot(array0.doc)
+
+  array0.insert(2, ['user1item2'])
+  testConnector.syncAll()
+  array1.insert(3, ['user2item2'])
+  testConnector.syncAll()
+
+  const docRestored0 = Y.createDocFromSnapshot(array0.doc, snap)
+  t.compare(docRestored0.getArray('array').toArray(), ['user1item1', 'user2item1'])
+
+  const docRestored1 = Y.createDocFromSnapshot(array1.doc, snap)
+  t.compare(docRestored1.getArray('array').toArray(), ['user1item1', 'user2item1'])
+}

tests/testHelper.js

@@ -1,19 +1,18 @@
+
+import * as t from 'lib0/testing'
+import * as prng from 'lib0/prng'
+import * as encoding from 'lib0/encoding'
+import * as decoding from 'lib0/decoding'
+import * as syncProtocol from 'y-protocols/sync'
+import * as object from 'lib0/object'
+import * as map from 'lib0/map'
 import * as Y from '../src/index.js'
+export * from '../src/index.js'
 
-import {
-  createDeleteSetFromStructStore,
-  getStateVector,
-  Item,
-  DeleteItem, DeleteSet, StructStore, Doc // eslint-disable-line
-} from '../src/internals.js'
-
-import * as t from 'lib0/testing.js'
-import * as prng from 'lib0/prng.js'
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-import * as syncProtocol from 'y-protocols/sync.js'
-import * as object from 'lib0/object.js'
-export * from '../src/internals.js'
+if (typeof window !== 'undefined') {
+  // @ts-ignore
+  window.Y = Y // eslint-disable-line
+}
 
 /**
  * @param {TestYInstance} y // publish message created by `y` to all other online clients
@@ -29,7 +28,40 @@ const broadcastMessage = (y, m) => {
   }
 }
 
-export class TestYInstance extends Doc {
+export let useV2 = false
+
+export const encV1 = {
+  encodeStateAsUpdate: Y.encodeStateAsUpdate,
+  mergeUpdates: Y.mergeUpdates,
+  applyUpdate: Y.applyUpdate,
+  logUpdate: Y.logUpdate,
+  updateEventName: 'update',
+  diffUpdate: Y.diffUpdate
+}
+
+export const encV2 = {
+  encodeStateAsUpdate: Y.encodeStateAsUpdateV2,
+  mergeUpdates: Y.mergeUpdatesV2,
+  applyUpdate: Y.applyUpdateV2,
+  logUpdate: Y.logUpdateV2,
+  updateEventName: 'updateV2',
+  diffUpdate: Y.diffUpdateV2
+}
+
+export let enc = encV1
+
+const useV1Encoding = () => {
+  useV2 = false
+  enc = encV1
+}
+
+const useV2Encoding = () => {
+  console.error('sync protocol doesnt support v2 protocol yet, fallback to v1 encoding') // @Todo
+  useV2 = false
+  enc = encV1
+}
+
+export class TestYInstance extends Y.Doc {
   /**
    * @param {TestConnector} testConnector
    * @param {number} clientID
@@ -46,13 +78,20 @@ export class TestYInstance extends Doc {
      */
     this.receiving = new Map()
     testConnector.allConns.add(this)
+    /**
+     * The list of received updates.
+     * We are going to merge them later using Y.mergeUpdates and check if the resulting document is correct.
+     * @type {Array<Uint8Array>}
+     */
+    this.updates = []
     // set up observe on local model
-    this.on('update', /** @param {Uint8Array} update @param {any} origin */ (update, origin) => {
+    this.on(enc.updateEventName, /** @param {Uint8Array} update @param {any} origin */ (update, origin) => {
       if (origin !== testConnector) {
         const encoder = encoding.createEncoder()
         syncProtocol.writeUpdate(encoder, update)
         broadcastMessage(this, encoding.toUint8Array(encoder))
       }
+      this.updates.push(update)
     })
     this.connect()
   }
@@ -95,12 +134,7 @@ export class TestYInstance extends Doc {
    * @param {TestYInstance} remoteClient
    */
   _receive (message, remoteClient) {
-    let messages = this.receiving.get(remoteClient)
-    if (messages === undefined) {
-      messages = []
-      this.receiving.set(remoteClient, messages)
-    }
-    messages.push(message)
+    map.setIfUndefined(this.receiving, remoteClient, () => []).push(message)
   }
 }
 
@@ -240,19 +274,27 @@ export const init = (tc, { users = 5 } = {}, initTestObject) => {
     users: []
   }
   const gen = tc.prng
+  // choose an encoding approach at random
+  if (prng.bool(gen)) {
+    useV2Encoding()
+  } else {
+    useV1Encoding()
+  }
+
   const testConnector = new TestConnector(gen)
   result.testConnector = testConnector
   for (let i = 0; i < users; i++) {
     const y = testConnector.createY(i)
     y.clientID = i
     result.users.push(y)
-    result['array' + i] = y.get('array', Y.Array)
-    result['map' + i] = y.get('map', Y.Map)
+    result['array' + i] = y.getArray('array')
+    result['map' + i] = y.getMap('map')
     result['xml' + i] = y.get('xml', Y.XmlElement)
-    result['text' + i] = y.get('text', Y.Text)
+    result['text' + i] = y.getText('text')
   }
   testConnector.syncAll()
   result.testObjects = result.users.map(initTestObject || (() => null))
+  useV1Encoding()
   return /** @type {any} */ (result)
 }
 
@@ -267,15 +309,22 @@ export const init = (tc, { users = 5 } = {}, initTestObject) => {
  */
 export const compare = users => {
   users.forEach(u => u.connect())
-  while (users[0].tc.flushAllMessages()) {}
+  while (users[0].tc.flushAllMessages()) {} // eslint-disable-line
+  // For each document, merge all received document updates with Y.mergeUpdates and create a new document which will be added to the list of "users"
+  // This ensures that mergeUpdates works correctly
+  const mergedDocs = users.map(user => {
+    const ydoc = new Y.Doc()
+    enc.applyUpdate(ydoc, enc.mergeUpdates(user.updates))
+    return ydoc
+  })
+  users.push(.../** @type {any} */(mergedDocs))
   const userArrayValues = users.map(u => u.getArray('array').toJSON())
   const userMapValues = users.map(u => u.getMap('map').toJSON())
   const userXmlValues = users.map(u => u.get('xml', Y.XmlElement).toString())
   const userTextValues = users.map(u => u.getText('text').toDelta())
   for (const u of users) {
-    t.assert(u.store.pendingDeleteReaders.length === 0)
-    t.assert(u.store.pendingStack.length === 0)
-    t.assert(u.store.pendingClientsStructRefs.size === 0)
+    t.assert(u.store.pendingDs === null)
+    t.assert(u.store.pendingStructs === null)
   }
   // Test Array iterator
   t.compare(users[0].getArray('array').toArray(), Array.from(users[0].getArray('array')))
@@ -298,24 +347,31 @@ export const compare = users => {
     t.compare(userMapValues[i], userMapValues[i + 1])
     t.compare(userXmlValues[i], userXmlValues[i + 1])
     t.compare(userTextValues[i].map(/** @param {any} a */ a => typeof a.insert === 'string' ? a.insert : ' ').join('').length, users[i].getText('text').length)
-    t.compare(userTextValues[i], userTextValues[i + 1])
-    t.compare(getStateVector(users[i].store), getStateVector(users[i + 1].store))
-    compareDS(createDeleteSetFromStructStore(users[i].store), createDeleteSetFromStructStore(users[i + 1].store))
+    t.compare(userTextValues[i], userTextValues[i + 1], '', (constructor, a, b) => {
+      if (a instanceof Y.AbstractType) {
+        t.compare(a.toJSON(), b.toJSON())
+      } else if (a !== b) {
+        t.fail('Deltas dont match')
+      }
+      return true
+    })
+    t.compare(Y.encodeStateVector(users[i]), Y.encodeStateVector(users[i + 1]))
+    compareDS(Y.createDeleteSetFromStructStore(users[i].store), Y.createDeleteSetFromStructStore(users[i + 1].store))
     compareStructStores(users[i].store, users[i + 1].store)
   }
   users.map(u => u.destroy())
 }
 
 /**
- * @param {Item?} a
- * @param {Item?} b
+ * @param {Y.Item?} a
+ * @param {Y.Item?} b
  * @return {boolean}
  */
 export const compareItemIDs = (a, b) => a === b || (a !== null && b != null && Y.compareIDs(a.id, b.id))
 
 /**
- * @param {StructStore} ss1
- * @param {StructStore} ss2
+ * @param {import('../src/internals').StructStore} ss1
+ * @param {import('../src/internals').StructStore} ss2
  */
 export const compareStructStores = (ss1, ss2) => {
   t.assert(ss1.clients.size === ss2.clients.size)
@@ -330,13 +386,14 @@ export const compareStructStores = (ss1, ss2) => {
         s1.constructor !== s2.constructor ||
         !Y.compareIDs(s1.id, s2.id) ||
         s1.deleted !== s2.deleted ||
+        // @ts-ignore
         s1.length !== s2.length
       ) {
         t.fail('Structs dont match')
       }
-      if (s1 instanceof Item) {
+      if (s1 instanceof Y.Item) {
         if (
-          !(s2 instanceof Item) ||
+          !(s2 instanceof Y.Item) ||
           !((s1.left === null && s2.left === null) || (s1.left !== null && s2.left !== null && Y.compareIDs(s1.left.lastId, s2.left.lastId))) ||
           !compareItemIDs(s1.right, s2.right) ||
           !Y.compareIDs(s1.origin, s2.origin) ||
@@ -356,13 +413,13 @@ export const compareStructStores = (ss1, ss2) => {
 }
 
 /**
- * @param {DeleteSet} ds1
- * @param {DeleteSet} ds2
+ * @param {import('../src/internals').DeleteSet} ds1
+ * @param {import('../src/internals').DeleteSet} ds2
  */
 export const compareDS = (ds1, ds2) => {
   t.assert(ds1.clients.size === ds2.clients.size)
-  for (const [client, deleteItems1] of ds1.clients) {
-    const deleteItems2 = /** @type {Array<DeleteItem>} */ (ds2.clients.get(client))
+  ds1.clients.forEach((deleteItems1, client) => {
+    const deleteItems2 = /** @type {Array<import('../src/internals').DeleteItem>} */ (ds2.clients.get(client))
     t.assert(deleteItems2 !== undefined && deleteItems1.length === deleteItems2.length)
     for (let i = 0; i < deleteItems1.length; i++) {
       const di1 = deleteItems1[i]
@@ -371,7 +428,7 @@ export const compareDS = (ds1, ds2) => {
         t.fail('DeleteSets dont match')
       }
     }
-  }
+  })
 }
 
 /**
@@ -393,21 +450,21 @@ export const applyRandomTests = (tc, mods, iterations, initTestObject) => {
   const result = init(tc, { users: 5 }, initTestObject)
   const { testConnector, users } = result
   for (let i = 0; i < iterations; i++) {
-    if (prng.int31(gen, 0, 100) <= 2) {
+    if (prng.int32(gen, 0, 100) <= 2) {
       // 2% chance to disconnect/reconnect a random user
       if (prng.bool(gen)) {
         testConnector.disconnectRandom()
       } else {
         testConnector.reconnectRandom()
       }
-    } else if (prng.int31(gen, 0, 100) <= 1) {
+    } else if (prng.int32(gen, 0, 100) <= 1) {
       // 1% chance to flush all
       testConnector.flushAllMessages()
-    } else if (prng.int31(gen, 0, 100) <= 50) {
+    } else if (prng.int32(gen, 0, 100) <= 50) {
       // 50% chance to flush a random message
       testConnector.flushRandomMessage()
     }
-    const user = prng.int31(gen, 0, users.length - 1)
+    const user = prng.int32(gen, 0, users.length - 1)
     const test = prng.oneOf(gen, mods)
     test(users[user], gen, result.testObjects[user])
   }

tests/undo-redo.tests.js

@@ -1,18 +1,27 @@
 import { init, compare, applyRandomTests, Doc } from './testHelper.js' // eslint-disable-line
 
-import {
-  UndoManager
-} from '../src/internals.js'
-
 import * as Y from '../src/index.js'
-import * as t from 'lib0/testing.js'
+import * as t from 'lib0/testing'
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testInfiniteCaptureTimeout = tc => {
+  const { array0 } = init(tc, { users: 3 })
+  const undoManager = new Y.UndoManager(array0, { captureTimeout: Number.MAX_VALUE })
+  array0.push([1, 2, 3])
+  undoManager.stopCapturing()
+  array0.push([4, 5, 6])
+  undoManager.undo()
+  t.compare(array0.toArray(), [1, 2, 3])
+}
 
 /**
  * @param {t.TestCase} tc
  */
 export const testUndoText = tc => {
   const { testConnector, text0, text1 } = init(tc, { users: 3 })
-  const undoManager = new UndoManager(text0)
+  const undoManager = new Y.UndoManager(text0)
 
   // items that are added & deleted in the same transaction won't be undo
   text0.insert(0, 'test')
@@ -53,13 +62,49 @@ export const testUndoText = tc => {
   t.compare(text0.toDelta(), [{ insert: 'b' }, { insert: 'cxy', attributes: { bold: true } }, { insert: 'z' }])
 }
 
+/**
+ * Test case to fix #241
+ * @param {t.TestCase} tc
+ */
+export const testEmptyTypeScope = tc => {
+  const ydoc = new Y.Doc()
+  const um = new Y.UndoManager([], { doc: ydoc })
+  const yarray = ydoc.getArray()
+  um.addToScope(yarray)
+  yarray.insert(0, [1])
+  um.undo()
+  t.assert(yarray.length === 0)
+}
+
+/**
+ * Test case to fix #241
+ * @param {t.TestCase} tc
+ */
+export const testDoubleUndo = tc => {
+  const doc = new Y.Doc()
+  const text = doc.getText()
+  text.insert(0, '1221')
+
+  const manager = new Y.UndoManager(text)
+
+  text.insert(2, '3')
+  text.insert(3, '3')
+
+  manager.undo()
+  manager.undo()
+
+  text.insert(2, '3')
+
+  t.compareStrings(text.toString(), '12321')
+}
+
 /**
  * @param {t.TestCase} tc
  */
 export const testUndoMap = tc => {
   const { testConnector, map0, map1 } = init(tc, { users: 2 })
   map0.set('a', 0)
-  const undoManager = new UndoManager(map0)
+  const undoManager = new Y.UndoManager(map0)
   map0.set('a', 1)
   undoManager.undo()
   t.assert(map0.get('a') === 0)
@@ -98,7 +143,7 @@ export const testUndoMap = tc => {
  */
 export const testUndoArray = tc => {
   const { testConnector, array0, array1 } = init(tc, { users: 3 })
-  const undoManager = new UndoManager(array0)
+  const undoManager = new Y.UndoManager(array0)
   array0.insert(0, [1, 2, 3])
   array1.insert(0, [4, 5, 6])
   testConnector.syncAll()
@@ -149,7 +194,7 @@ export const testUndoArray = tc => {
  */
 export const testUndoXml = tc => {
   const { xml0 } = init(tc, { users: 3 })
-  const undoManager = new UndoManager(xml0)
+  const undoManager = new Y.UndoManager(xml0)
   const child = new Y.XmlElement('p')
   xml0.insert(0, [child])
   const textchild = new Y.XmlText('content')
@@ -174,15 +219,17 @@ export const testUndoXml = tc => {
  */
 export const testUndoEvents = tc => {
   const { text0 } = init(tc, { users: 3 })
-  const undoManager = new UndoManager(text0)
+  const undoManager = new Y.UndoManager(text0)
   let counter = 0
   let receivedMetadata = -1
   undoManager.on('stack-item-added', /** @param {any} event */ event => {
     t.assert(event.type != null)
+    t.assert(event.changedParentTypes != null && event.changedParentTypes.has(text0))
     event.stackItem.meta.set('test', counter++)
   })
   undoManager.on('stack-item-popped', /** @param {any} event */ event => {
     t.assert(event.type != null)
+    t.assert(event.changedParentTypes != null && event.changedParentTypes.has(text0))
     receivedMetadata = event.stackItem.meta.get('test')
   })
   text0.insert(0, 'abc')
@@ -198,7 +245,7 @@ export const testUndoEvents = tc => {
 export const testTrackClass = tc => {
   const { users, text0 } = init(tc, { users: 3 })
   // only track origins that are numbers
-  const undoManager = new UndoManager(text0, { trackedOrigins: new Set([Number]) })
+  const undoManager = new Y.UndoManager(text0, { trackedOrigins: new Set([Number]) })
   users[0].transact(() => {
     text0.insert(0, 'abc')
   }, 42)
@@ -216,8 +263,8 @@ export const testTypeScope = tc => {
   const text0 = new Y.Text()
   const text1 = new Y.Text()
   array0.insert(0, [text0, text1])
-  const undoManager = new UndoManager(text0)
-  const undoManagerBoth = new UndoManager([text0, text1])
+  const undoManager = new Y.UndoManager(text0)
+  const undoManagerBoth = new Y.UndoManager([text0, text1])
   text1.insert(0, 'abc')
   t.assert(undoManager.undoStack.length === 0)
   t.assert(undoManagerBoth.undoStack.length === 1)
@@ -228,15 +275,35 @@ export const testTypeScope = tc => {
   t.assert(text1.toString() === '')
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testUndoInEmbed = tc => {
+  const { text0 } = init(tc, { users: 3 })
+  const undoManager = new Y.UndoManager(text0)
+  const nestedText = new Y.Text('initial text')
+  undoManager.stopCapturing()
+  text0.insertEmbed(0, nestedText, { bold: true })
+  t.assert(nestedText.toString() === 'initial text')
+  undoManager.stopCapturing()
+  nestedText.delete(0, nestedText.length)
+  nestedText.insert(0, 'other text')
+  t.assert(nestedText.toString() === 'other text')
+  undoManager.undo()
+  t.assert(nestedText.toString() === 'initial text')
+  undoManager.undo()
+  t.assert(text0.length === 0)
+}
+
 /**
  * @param {t.TestCase} tc
  */
 export const testUndoDeleteFilter = tc => {
   /**
-   * @type {Array<Y.Map<any>>}
+   * @type {Y.Array<any>}
    */
   const array0 = /** @type {any} */ (init(tc, { users: 3 }).array0)
-  const undoManager = new UndoManager(array0, { deleteFilter: item => !(item instanceof Y.Item) || (item.content instanceof Y.ContentType && item.content.type._map.size === 0) })
+  const undoManager = new Y.UndoManager(array0, { deleteFilter: item => !(item instanceof Y.Item) || (item.content instanceof Y.ContentType && item.content.type._map.size === 0) })
   const map0 = new Y.Map()
   map0.set('hi', 1)
   const map1 = new Y.Map()
@@ -246,3 +313,334 @@ export const testUndoDeleteFilter = tc => {
   array0.get(0)
   t.assert(Array.from(array0.get(0).keys()).length === 1)
 }
+
+/**
+ * This issue has been reported in https://discuss.yjs.dev/t/undomanager-with-external-updates/454/6
+ * @param {t.TestCase} tc
+ */
+export const testUndoUntilChangePerformed = tc => {
+  const doc = new Y.Doc()
+  const doc2 = new Y.Doc()
+  doc.on('update', update => Y.applyUpdate(doc2, update))
+  doc2.on('update', update => Y.applyUpdate(doc, update))
+
+  const yArray = doc.getArray('array')
+  const yArray2 = doc2.getArray('array')
+  const yMap = new Y.Map()
+  yMap.set('hello', 'world')
+  yArray.push([yMap])
+  const yMap2 = new Y.Map()
+  yMap2.set('key', 'value')
+  yArray.push([yMap2])
+
+  const undoManager = new Y.UndoManager([yArray], { trackedOrigins: new Set([doc.clientID]) })
+  const undoManager2 = new Y.UndoManager([doc2.get('array')], { trackedOrigins: new Set([doc2.clientID]) })
+
+  Y.transact(doc, () => yMap2.set('key', 'value modified'), doc.clientID)
+  undoManager.stopCapturing()
+  Y.transact(doc, () => yMap.set('hello', 'world modified'), doc.clientID)
+  Y.transact(doc2, () => yArray2.delete(0), doc2.clientID)
+  undoManager2.undo()
+  undoManager.undo()
+  t.compareStrings(yMap2.get('key'), 'value')
+}
+
+/**
+ * This issue has been reported in https://github.com/yjs/yjs/issues/317
+ * @param {t.TestCase} tc
+ */
+export const testUndoNestedUndoIssue = tc => {
+  const doc = new Y.Doc({ gc: false })
+  const design = doc.getMap()
+  const undoManager = new Y.UndoManager(design, { captureTimeout: 0 })
+
+  /**
+   * @type {Y.Map<any>}
+   */
+  const text = new Y.Map()
+
+  const blocks1 = new Y.Array()
+  const blocks1block = new Y.Map()
+
+  doc.transact(() => {
+    blocks1block.set('text', 'Type Something')
+    blocks1.push([blocks1block])
+    text.set('blocks', blocks1block)
+    design.set('text', text)
+  })
+
+  const blocks2 = new Y.Array()
+  const blocks2block = new Y.Map()
+  doc.transact(() => {
+    blocks2block.set('text', 'Something')
+    blocks2.push([blocks2block])
+    text.set('blocks', blocks2block)
+  })
+
+  const blocks3 = new Y.Array()
+  const blocks3block = new Y.Map()
+  doc.transact(() => {
+    blocks3block.set('text', 'Something Else')
+    blocks3.push([blocks3block])
+    text.set('blocks', blocks3block)
+  })
+
+  t.compare(design.toJSON(), { text: { blocks: { text: 'Something Else' } } })
+  undoManager.undo()
+  t.compare(design.toJSON(), { text: { blocks: { text: 'Something' } } })
+  undoManager.undo()
+  t.compare(design.toJSON(), { text: { blocks: { text: 'Type Something' } } })
+  undoManager.undo()
+  t.compare(design.toJSON(), { })
+  undoManager.redo()
+  t.compare(design.toJSON(), { text: { blocks: { text: 'Type Something' } } })
+  undoManager.redo()
+  t.compare(design.toJSON(), { text: { blocks: { text: 'Something' } } })
+  undoManager.redo()
+  t.compare(design.toJSON(), { text: { blocks: { text: 'Something Else' } } })
+}
+
+/**
+ * This issue has been reported in https://github.com/yjs/yjs/issues/355
+ *
+ * @param {t.TestCase} tc
+ */
+export const testConsecutiveRedoBug = tc => {
+  const doc = new Y.Doc()
+  const yRoot = doc.getMap()
+  const undoMgr = new Y.UndoManager(yRoot)
+
+  let yPoint = new Y.Map()
+  yPoint.set('x', 0)
+  yPoint.set('y', 0)
+  yRoot.set('a', yPoint)
+  undoMgr.stopCapturing()
+
+  yPoint.set('x', 100)
+  yPoint.set('y', 100)
+  undoMgr.stopCapturing()
+
+  yPoint.set('x', 200)
+  yPoint.set('y', 200)
+  undoMgr.stopCapturing()
+
+  yPoint.set('x', 300)
+  yPoint.set('y', 300)
+  undoMgr.stopCapturing()
+
+  t.compare(yPoint.toJSON(), { x: 300, y: 300 })
+
+  undoMgr.undo() // x=200, y=200
+  t.compare(yPoint.toJSON(), { x: 200, y: 200 })
+  undoMgr.undo() // x=100, y=100
+  t.compare(yPoint.toJSON(), { x: 100, y: 100 })
+  undoMgr.undo() // x=0, y=0
+  t.compare(yPoint.toJSON(), { x: 0, y: 0 })
+  undoMgr.undo() // nil
+  t.compare(yRoot.get('a'), undefined)
+
+  undoMgr.redo() // x=0, y=0
+  yPoint = yRoot.get('a')
+
+  t.compare(yPoint.toJSON(), { x: 0, y: 0 })
+  undoMgr.redo() // x=100, y=100
+  t.compare(yPoint.toJSON(), { x: 100, y: 100 })
+  undoMgr.redo() // x=200, y=200
+  t.compare(yPoint.toJSON(), { x: 200, y: 200 })
+  undoMgr.redo() // expected x=300, y=300, actually nil
+  t.compare(yPoint.toJSON(), { x: 300, y: 300 })
+}
+
+/**
+ * This issue has been reported in https://github.com/yjs/yjs/issues/304
+ *
+ * @param {t.TestCase} tc
+ */
+export const testUndoXmlBug = tc => {
+  const origin = 'origin'
+  const doc = new Y.Doc()
+  const fragment = doc.getXmlFragment('t')
+  const undoManager = new Y.UndoManager(fragment, {
+    captureTimeout: 0,
+    trackedOrigins: new Set([origin])
+  })
+
+  // create element
+  doc.transact(() => {
+    const e = new Y.XmlElement('test-node')
+    e.setAttribute('a', '100')
+    e.setAttribute('b', '0')
+    fragment.insert(fragment.length, [e])
+  }, origin)
+
+  // change one attribute
+  doc.transact(() => {
+    const e = fragment.get(0)
+    e.setAttribute('a', '200')
+  }, origin)
+
+  // change both attributes
+  doc.transact(() => {
+    const e = fragment.get(0)
+    e.setAttribute('a', '180')
+    e.setAttribute('b', '50')
+  }, origin)
+
+  undoManager.undo()
+  undoManager.undo()
+  undoManager.undo()
+
+  undoManager.redo()
+  undoManager.redo()
+  undoManager.redo()
+  t.compare(fragment.toString(), '<test-node a="180" b="50"></test-node>')
+}
+
+/**
+ * This issue has been reported in https://github.com/yjs/yjs/issues/343
+ *
+ * @param {t.TestCase} tc
+ */
+export const testUndoBlockBug = tc => {
+  const doc = new Y.Doc({ gc: false })
+  const design = doc.getMap()
+
+  const undoManager = new Y.UndoManager(design, { captureTimeout: 0 })
+
+  const text = new Y.Map()
+
+  const blocks1 = new Y.Array()
+  const blocks1block = new Y.Map()
+  doc.transact(() => {
+    blocks1block.set('text', '1')
+    blocks1.push([blocks1block])
+
+    text.set('blocks', blocks1block)
+    design.set('text', text)
+  })
+
+  const blocks2 = new Y.Array()
+  const blocks2block = new Y.Map()
+  doc.transact(() => {
+    blocks2block.set('text', '2')
+    blocks2.push([blocks2block])
+    text.set('blocks', blocks2block)
+  })
+
+  const blocks3 = new Y.Array()
+  const blocks3block = new Y.Map()
+  doc.transact(() => {
+    blocks3block.set('text', '3')
+    blocks3.push([blocks3block])
+    text.set('blocks', blocks3block)
+  })
+
+  const blocks4 = new Y.Array()
+  const blocks4block = new Y.Map()
+  doc.transact(() => {
+    blocks4block.set('text', '4')
+    blocks4.push([blocks4block])
+    text.set('blocks', blocks4block)
+  })
+
+  // {"text":{"blocks":{"text":"4"}}}
+  undoManager.undo() // {"text":{"blocks":{"3"}}}
+  undoManager.undo() // {"text":{"blocks":{"text":"2"}}}
+  undoManager.undo() // {"text":{"blocks":{"text":"1"}}}
+  undoManager.undo() // {}
+  undoManager.redo() // {"text":{"blocks":{"text":"1"}}}
+  undoManager.redo() // {"text":{"blocks":{"text":"2"}}}
+  undoManager.redo() // {"text":{"blocks":{"text":"3"}}}
+  undoManager.redo() // {"text":{}}
+  t.compare(design.toJSON(), { text: { blocks: { text: '4' } } })
+}
+
+/**
+ * Undo text formatting delete should not corrupt peer state.
+ *
+ * @see https://github.com/yjs/yjs/issues/392
+ * @param {t.TestCase} tc
+ */
+export const testUndoDeleteTextFormat = tc => {
+  const doc = new Y.Doc()
+  const text = doc.getText()
+  text.insert(0, 'Attack ships on fire off the shoulder of Orion.')
+  const doc2 = new Y.Doc()
+  const text2 = doc2.getText()
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+  const undoManager = new Y.UndoManager(text)
+
+  text.format(13, 7, { bold: true })
+  undoManager.stopCapturing()
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+
+  text.format(16, 4, { bold: null })
+  undoManager.stopCapturing()
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+
+  undoManager.undo()
+  Y.applyUpdate(doc2, Y.encodeStateAsUpdate(doc))
+
+  const expect = [
+    { insert: 'Attack ships ' },
+    {
+      insert: 'on fire',
+      attributes: { bold: true }
+    },
+    { insert: ' off the shoulder of Orion.' }
+  ]
+  t.compare(text.toDelta(), expect)
+  t.compare(text2.toDelta(), expect)
+}
+
+/**
+ * Undo text formatting delete should not corrupt peer state.
+ *
+ * @see https://github.com/yjs/yjs/issues/392
+ * @param {t.TestCase} tc
+ */
+export const testBehaviorOfIgnoreremotemapchangesProperty = tc => {
+  const doc = new Y.Doc()
+  const doc2 = new Y.Doc()
+  doc.on('update', update => Y.applyUpdate(doc2, update, doc))
+  doc2.on('update', update => Y.applyUpdate(doc, update, doc2))
+  const map1 = doc.getMap()
+  const map2 = doc2.getMap()
+  const um1 = new Y.UndoManager(map1, { ignoreRemoteMapChanges: true })
+  map1.set('x', 1)
+  map2.set('x', 2)
+  map1.set('x', 3)
+  map2.set('x', 4)
+  um1.undo()
+  t.assert(map1.get('x') === 2)
+  t.assert(map2.get('x') === 2)
+}
+
+/**
+ * Special deletion case.
+ *
+ * @see https://github.com/yjs/yjs/issues/447
+ * @param {t.TestCase} tc
+ */
+export const testSpecialDeletionCase = tc => {
+  const origin = 'undoable'
+  const doc = new Y.Doc()
+  const fragment = doc.getXmlFragment()
+  const undoManager = new Y.UndoManager(fragment, { trackedOrigins: new Set([origin]) })
+  doc.transact(() => {
+    const e = new Y.XmlElement('test')
+    e.setAttribute('a', '1')
+    e.setAttribute('b', '2')
+    fragment.insert(0, [e])
+  })
+  t.compareStrings(fragment.toString(), '<test a="1" b="2"></test>')
+  doc.transact(() => {
+    // change attribute "b" and delete test-node
+    const e = fragment.get(0)
+    e.setAttribute('b', '3')
+    fragment.delete(0)
+  }, origin)
+  t.compareStrings(fragment.toString(), '')
+  undoManager.undo()
+  t.compareStrings(fragment.toString(), '<test a="1" b="2"></test>')
+}

tests/updates.tests.js

@@ -0,0 +1,306 @@
+import * as t from 'lib0/testing'
+import { init, compare } from './testHelper.js' // eslint-disable-line
+import * as Y from '../src/index.js'
+import { readClientsStructRefs, readDeleteSet, UpdateDecoderV2, UpdateEncoderV2, writeDeleteSet } from '../src/internals.js'
+import * as encoding from 'lib0/encoding'
+import * as decoding from 'lib0/decoding'
+
+/**
+ * @typedef {Object} Enc
+ * @property {function(Array<Uint8Array>):Uint8Array} Enc.mergeUpdates
+ * @property {function(Y.Doc):Uint8Array} Enc.encodeStateAsUpdate
+ * @property {function(Y.Doc, Uint8Array):void} Enc.applyUpdate
+ * @property {function(Uint8Array):void} Enc.logUpdate
+ * @property {function(Uint8Array):{from:Map<number,number>,to:Map<number,number>}} Enc.parseUpdateMeta
+ * @property {function(Y.Doc):Uint8Array} Enc.encodeStateVector
+ * @property {function(Uint8Array):Uint8Array} Enc.encodeStateVectorFromUpdate
+ * @property {string} Enc.updateEventName
+ * @property {string} Enc.description
+ * @property {function(Uint8Array, Uint8Array):Uint8Array} Enc.diffUpdate
+ */
+
+/**
+ * @type {Enc}
+ */
+const encV1 = {
+  mergeUpdates: Y.mergeUpdates,
+  encodeStateAsUpdate: Y.encodeStateAsUpdate,
+  applyUpdate: Y.applyUpdate,
+  logUpdate: Y.logUpdate,
+  parseUpdateMeta: Y.parseUpdateMeta,
+  encodeStateVectorFromUpdate: Y.encodeStateVectorFromUpdate,
+  encodeStateVector: Y.encodeStateVector,
+  updateEventName: 'update',
+  description: 'V1',
+  diffUpdate: Y.diffUpdate
+}
+
+/**
+ * @type {Enc}
+ */
+const encV2 = {
+  mergeUpdates: Y.mergeUpdatesV2,
+  encodeStateAsUpdate: Y.encodeStateAsUpdateV2,
+  applyUpdate: Y.applyUpdateV2,
+  logUpdate: Y.logUpdateV2,
+  parseUpdateMeta: Y.parseUpdateMetaV2,
+  encodeStateVectorFromUpdate: Y.encodeStateVectorFromUpdateV2,
+  encodeStateVector: Y.encodeStateVector,
+  updateEventName: 'updateV2',
+  description: 'V2',
+  diffUpdate: Y.diffUpdateV2
+}
+
+/**
+ * @type {Enc}
+ */
+const encDoc = {
+  mergeUpdates: (updates) => {
+    const ydoc = new Y.Doc({ gc: false })
+    updates.forEach(update => {
+      Y.applyUpdateV2(ydoc, update)
+    })
+    return Y.encodeStateAsUpdateV2(ydoc)
+  },
+  encodeStateAsUpdate: Y.encodeStateAsUpdateV2,
+  applyUpdate: Y.applyUpdateV2,
+  logUpdate: Y.logUpdateV2,
+  parseUpdateMeta: Y.parseUpdateMetaV2,
+  encodeStateVectorFromUpdate: Y.encodeStateVectorFromUpdateV2,
+  encodeStateVector: Y.encodeStateVector,
+  updateEventName: 'updateV2',
+  description: 'Merge via Y.Doc',
+  /**
+   * @param {Uint8Array} update
+   * @param {Uint8Array} sv
+   */
+  diffUpdate: (update, sv) => {
+    const ydoc = new Y.Doc({ gc: false })
+    Y.applyUpdateV2(ydoc, update)
+    return Y.encodeStateAsUpdateV2(ydoc, sv)
+  }
+}
+
+const encoders = [encV1, encV2, encDoc]
+
+/**
+ * @param {Array<Y.Doc>} users
+ * @param {Enc} enc
+ */
+const fromUpdates = (users, enc) => {
+  const updates = users.map(user =>
+    enc.encodeStateAsUpdate(user)
+  )
+  const ydoc = new Y.Doc()
+  enc.applyUpdate(ydoc, enc.mergeUpdates(updates))
+  return ydoc
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testMergeUpdates = tc => {
+  const { users, array0, array1 } = init(tc, { users: 3 })
+
+  array0.insert(0, [1])
+  array1.insert(0, [2])
+
+  compare(users)
+  encoders.forEach(enc => {
+    const merged = fromUpdates(users, enc)
+    t.compareArrays(array0.toArray(), merged.getArray('array').toArray())
+  })
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testKeyEncoding = tc => {
+  const { users, text0, text1 } = init(tc, { users: 2 })
+
+  text0.insert(0, 'a', { italic: true })
+  text0.insert(0, 'b')
+  text0.insert(0, 'c', { italic: true })
+
+  const update = Y.encodeStateAsUpdateV2(users[0])
+  Y.applyUpdateV2(users[1], update)
+
+  t.compare(text1.toDelta(), [{ insert: 'c', attributes: { italic: true } }, { insert: 'b' }, { insert: 'a', attributes: { italic: true } }])
+
+  compare(users)
+}
+
+/**
+ * @param {Y.Doc} ydoc
+ * @param {Array<Uint8Array>} updates - expecting at least 4 updates
+ * @param {Enc} enc
+ * @param {boolean} hasDeletes
+ */
+const checkUpdateCases = (ydoc, updates, enc, hasDeletes) => {
+  const cases = []
+
+  // Case 1: Simple case, simply merge everything
+  cases.push(enc.mergeUpdates(updates))
+
+  // Case 2: Overlapping updates
+  cases.push(enc.mergeUpdates([
+    enc.mergeUpdates(updates.slice(2)),
+    enc.mergeUpdates(updates.slice(0, 2))
+  ]))
+
+  // Case 3: Overlapping updates
+  cases.push(enc.mergeUpdates([
+    enc.mergeUpdates(updates.slice(2)),
+    enc.mergeUpdates(updates.slice(1, 3)),
+    updates[0]
+  ]))
+
+  // Case 4: Separated updates (containing skips)
+  cases.push(enc.mergeUpdates([
+    enc.mergeUpdates([updates[0], updates[2]]),
+    enc.mergeUpdates([updates[1], updates[3]]),
+    enc.mergeUpdates(updates.slice(4))
+  ]))
+
+  // Case 5: overlapping with many duplicates
+  cases.push(enc.mergeUpdates(cases))
+
+  // const targetState = enc.encodeStateAsUpdate(ydoc)
+  // t.info('Target State: ')
+  // enc.logUpdate(targetState)
+
+  cases.forEach((mergedUpdates, i) => {
+    // t.info('State Case $' + i + ':')
+    // enc.logUpdate(updates)
+    const merged = new Y.Doc({ gc: false })
+    enc.applyUpdate(merged, mergedUpdates)
+    t.compareArrays(merged.getArray().toArray(), ydoc.getArray().toArray())
+    t.compare(enc.encodeStateVector(merged), enc.encodeStateVectorFromUpdate(mergedUpdates))
+
+    if (enc.updateEventName !== 'update') { // @todo should this also work on legacy updates?
+      for (let j = 1; j < updates.length; j++) {
+        const partMerged = enc.mergeUpdates(updates.slice(j))
+        const partMeta = enc.parseUpdateMeta(partMerged)
+        const targetSV = Y.encodeStateVectorFromUpdateV2(Y.mergeUpdatesV2(updates.slice(0, j)))
+        const diffed = enc.diffUpdate(mergedUpdates, targetSV)
+        const diffedMeta = enc.parseUpdateMeta(diffed)
+        t.compare(partMeta, diffedMeta)
+        {
+          // We can'd do the following
+          //  - t.compare(diffed, mergedDeletes)
+          // because diffed contains the set of all deletes.
+          // So we add all deletes from `diffed` to `partDeletes` and compare then
+          const decoder = decoding.createDecoder(diffed)
+          const updateDecoder = new UpdateDecoderV2(decoder)
+          readClientsStructRefs(updateDecoder, new Y.Doc())
+          const ds = readDeleteSet(updateDecoder)
+          const updateEncoder = new UpdateEncoderV2()
+          encoding.writeVarUint(updateEncoder.restEncoder, 0) // 0 structs
+          writeDeleteSet(updateEncoder, ds)
+          const deletesUpdate = updateEncoder.toUint8Array()
+          const mergedDeletes = Y.mergeUpdatesV2([deletesUpdate, partMerged])
+          if (!hasDeletes || enc !== encDoc) {
+            // deletes will almost definitely lead to different encoders because of the mergeStruct feature that is present in encDoc
+            t.compare(diffed, mergedDeletes)
+          }
+        }
+      }
+    }
+
+    const meta = enc.parseUpdateMeta(mergedUpdates)
+    meta.from.forEach((clock, client) => t.assert(clock === 0))
+    meta.to.forEach((clock, client) => {
+      const structs = /** @type {Array<Y.Item>} */ (merged.store.clients.get(client))
+      const lastStruct = structs[structs.length - 1]
+      t.assert(lastStruct.id.clock + lastStruct.length === clock)
+    })
+  })
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testMergeUpdates1 = tc => {
+  encoders.forEach((enc, i) => {
+    t.info(`Using encoder: ${enc.description}`)
+    const ydoc = new Y.Doc({ gc: false })
+    const updates = /** @type {Array<Uint8Array>} */ ([])
+    ydoc.on(enc.updateEventName, update => { updates.push(update) })
+
+    const array = ydoc.getArray()
+    array.insert(0, [1])
+    array.insert(0, [2])
+    array.insert(0, [3])
+    array.insert(0, [4])
+
+    checkUpdateCases(ydoc, updates, enc, false)
+  })
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testMergeUpdates2 = tc => {
+  encoders.forEach((enc, i) => {
+    t.info(`Using encoder: ${enc.description}`)
+    const ydoc = new Y.Doc({ gc: false })
+    const updates = /** @type {Array<Uint8Array>} */ ([])
+    ydoc.on(enc.updateEventName, update => { updates.push(update) })
+
+    const array = ydoc.getArray()
+    array.insert(0, [1, 2])
+    array.delete(1, 1)
+    array.insert(0, [3, 4])
+    array.delete(1, 2)
+
+    checkUpdateCases(ydoc, updates, enc, true)
+  })
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testMergePendingUpdates = tc => {
+  const yDoc = new Y.Doc()
+  /**
+   * @type {Array<Uint8Array>}
+   */
+  const serverUpdates = []
+  yDoc.on('update', (update, origin, c) => {
+    serverUpdates.splice(serverUpdates.length, 0, update)
+  })
+  const yText = yDoc.getText('textBlock')
+  yText.applyDelta([{ insert: 'r' }])
+  yText.applyDelta([{ insert: 'o' }])
+  yText.applyDelta([{ insert: 'n' }])
+  yText.applyDelta([{ insert: 'e' }])
+  yText.applyDelta([{ insert: 'n' }])
+
+  const yDoc1 = new Y.Doc()
+  Y.applyUpdate(yDoc1, serverUpdates[0])
+  const update1 = Y.encodeStateAsUpdate(yDoc1)
+
+  const yDoc2 = new Y.Doc()
+  Y.applyUpdate(yDoc2, update1)
+  Y.applyUpdate(yDoc2, serverUpdates[1])
+  const update2 = Y.encodeStateAsUpdate(yDoc2)
+
+  const yDoc3 = new Y.Doc()
+  Y.applyUpdate(yDoc3, update2)
+  Y.applyUpdate(yDoc3, serverUpdates[3])
+  const update3 = Y.encodeStateAsUpdate(yDoc3)
+
+  const yDoc4 = new Y.Doc()
+  Y.applyUpdate(yDoc4, update3)
+  Y.applyUpdate(yDoc4, serverUpdates[2])
+  const update4 = Y.encodeStateAsUpdate(yDoc4)
+
+  const yDoc5 = new Y.Doc()
+  Y.applyUpdate(yDoc5, update4)
+  Y.applyUpdate(yDoc5, serverUpdates[4])
+  // @ts-ignore
+  const update5 = Y.encodeStateAsUpdate(yDoc5) // eslint-disable-line
+
+  const yText5 = yDoc5.getText('textBlock')
+  t.compareStrings(yText5.toString(), 'nenor')
+}

tests/y-array.tests.js

@@ -1,9 +1,119 @@
 import { init, compare, applyRandomTests, Doc } from './testHelper.js' // eslint-disable-line
 
 import * as Y from '../src/index.js'
-import * as t from 'lib0/testing.js'
-import * as prng from 'lib0/prng.js'
-import * as math from 'lib0/math.js'
+import * as t from 'lib0/testing'
+import * as prng from 'lib0/prng'
+import * as math from 'lib0/math'
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testBasicUpdate = tc => {
+  const doc1 = new Y.Doc()
+  const doc2 = new Y.Doc()
+  doc1.getArray('array').insert(0, ['hi'])
+  const update = Y.encodeStateAsUpdate(doc1)
+  Y.applyUpdate(doc2, update)
+  t.compare(doc2.getArray('array').toArray(), ['hi'])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSlice = tc => {
+  const doc1 = new Y.Doc()
+  const arr = doc1.getArray('array')
+  arr.insert(0, [1, 2, 3])
+  t.compareArrays(arr.slice(0), [1, 2, 3])
+  t.compareArrays(arr.slice(1), [2, 3])
+  t.compareArrays(arr.slice(0, -1), [1, 2])
+  arr.insert(0, [0])
+  t.compareArrays(arr.slice(0), [0, 1, 2, 3])
+  t.compareArrays(arr.slice(0, 2), [0, 1])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testArrayFrom = tc => {
+  const doc1 = new Y.Doc()
+  const db1 = doc1.getMap('root')
+  const nestedArray1 = Y.Array.from([0, 1, 2])
+  db1.set('array', nestedArray1)
+  t.compare(nestedArray1.toArray(), [0, 1, 2])
+}
+
+/**
+ * Debugging yjs#297 - a critical bug connected to the search-marker approach
+ *
+ * @param {t.TestCase} tc
+ */
+export const testLengthIssue = tc => {
+  const doc1 = new Y.Doc()
+  const arr = doc1.getArray('array')
+  arr.push([0, 1, 2, 3])
+  arr.delete(0)
+  arr.insert(0, [0])
+  t.assert(arr.length === arr.toArray().length)
+  doc1.transact(() => {
+    arr.delete(1)
+    t.assert(arr.length === arr.toArray().length)
+    arr.insert(1, [1])
+    t.assert(arr.length === arr.toArray().length)
+    arr.delete(2)
+    t.assert(arr.length === arr.toArray().length)
+    arr.insert(2, [2])
+    t.assert(arr.length === arr.toArray().length)
+  })
+  t.assert(arr.length === arr.toArray().length)
+  arr.delete(1)
+  t.assert(arr.length === arr.toArray().length)
+  arr.insert(1, [1])
+  t.assert(arr.length === arr.toArray().length)
+}
+
+/**
+ * Debugging yjs#314
+ *
+ * @param {t.TestCase} tc
+ */
+export const testLengthIssue2 = tc => {
+  const doc = new Y.Doc()
+  const next = doc.getArray()
+  doc.transact(() => {
+    next.insert(0, ['group2'])
+  })
+  doc.transact(() => {
+    next.insert(1, ['rectangle3'])
+  })
+  doc.transact(() => {
+    next.delete(0)
+    next.insert(0, ['rectangle3'])
+  })
+  next.delete(1)
+  doc.transact(() => {
+    next.insert(1, ['ellipse4'])
+  })
+  doc.transact(() => {
+    next.insert(2, ['ellipse3'])
+  })
+  doc.transact(() => {
+    next.insert(3, ['ellipse2'])
+  })
+  doc.transact(() => {
+    doc.transact(() => {
+      t.fails(() => {
+        next.insert(5, ['rectangle2'])
+      })
+      next.insert(4, ['rectangle2'])
+    })
+    doc.transact(() => {
+      // this should not throw an error message
+      next.delete(4)
+    })
+  })
+  console.log(next.toArray())
+}
 
 /**
  * @param {t.TestCase} tc
@@ -37,7 +147,7 @@ export const testInsertThreeElementsTryRegetProperty = tc => {
  * @param {t.TestCase} tc
  */
 export const testConcurrentInsertWithThreeConflicts = tc => {
-  var { users, array0, array1, array2 } = init(tc, { users: 3 })
+  const { users, array0, array1, array2 } = init(tc, { users: 3 })
   array0.insert(0, [0])
   array1.insert(0, [1])
   array2.insert(0, [2])
@@ -80,7 +190,7 @@ export const testInsertionsInLateSync = tc => {
  * @param {t.TestCase} tc
  */
 export const testDisconnectReallyPreventsSendingMessages = tc => {
-  var { testConnector, users, array0, array1 } = init(tc, { users: 3 })
+  const { testConnector, users, array0, array1 } = init(tc, { users: 3 })
   array0.insert(0, ['x', 'y'])
   testConnector.flushAllMessages()
   users[1].disconnect()
@@ -192,6 +302,34 @@ export const testInsertAndDeleteEventsForTypes = tc => {
   compare(users)
 }
 
+/**
+ * This issue has been reported in https://discuss.yjs.dev/t/order-in-which-events-yielded-by-observedeep-should-be-applied/261/2
+ *
+ * Deep observers generate multiple events. When an array added at item at, say, position 0,
+ * and item 1 changed then the array-add event should fire first so that the change event
+ * path is correct. A array binding might lead to an inconsistent state otherwise.
+ *
+ * @param {t.TestCase} tc
+ */
+export const testObserveDeepEventOrder = tc => {
+  const { array0, users } = init(tc, { users: 2 })
+  /**
+   * @type {Array<any>}
+   */
+  let events = []
+  array0.observeDeep(e => {
+    events = e
+  })
+  array0.insert(0, [new Y.Map()])
+  users[0].transact(() => {
+    array0.get(0).set('a', 'a')
+    array0.insert(0, [0])
+  })
+  for (let i = 1; i < events.length; i++) {
+    t.assert(events[i - 1].path.length <= events[i].path.length, 'path size increases, fire top-level events first')
+  }
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -333,46 +471,57 @@ const getUniqueNumber = () => _uniqueNumber++
 const arrayTransactions = [
   function insert (user, gen) {
     const yarray = user.getArray('array')
-    var uniqueNumber = getUniqueNumber()
-    var content = []
-    var len = prng.int31(gen, 1, 4)
-    for (var i = 0; i < len; i++) {
+    const uniqueNumber = getUniqueNumber()
+    const content = []
+    const len = prng.int32(gen, 1, 4)
+    for (let i = 0; i < len; i++) {
       content.push(uniqueNumber)
     }
-    var pos = prng.int31(gen, 0, yarray.length)
+    const pos = prng.int32(gen, 0, yarray.length)
+    const oldContent = yarray.toArray()
     yarray.insert(pos, content)
+    oldContent.splice(pos, 0, ...content)
+    t.compareArrays(yarray.toArray(), oldContent) // we want to make sure that fastSearch markers insert at the correct position
   },
   function insertTypeArray (user, gen) {
     const yarray = user.getArray('array')
-    var pos = prng.int31(gen, 0, yarray.length)
+    const pos = prng.int32(gen, 0, yarray.length)
     yarray.insert(pos, [new Y.Array()])
-    var array2 = yarray.get(pos)
+    const array2 = yarray.get(pos)
     array2.insert(0, [1, 2, 3, 4])
   },
   function insertTypeMap (user, gen) {
     const yarray = user.getArray('array')
-    var pos = prng.int31(gen, 0, yarray.length)
+    const pos = prng.int32(gen, 0, yarray.length)
     yarray.insert(pos, [new Y.Map()])
-    var map = yarray.get(pos)
+    const map = yarray.get(pos)
     map.set('someprop', 42)
     map.set('someprop', 43)
     map.set('someprop', 44)
   },
+  function insertTypeNull (user, gen) {
+    const yarray = user.getArray('array')
+    const pos = prng.int32(gen, 0, yarray.length)
+    yarray.insert(pos, [null])
+  },
   function _delete (user, gen) {
     const yarray = user.getArray('array')
-    var length = yarray.length
+    const length = yarray.length
     if (length > 0) {
-      var somePos = prng.int31(gen, 0, length - 1)
-      var delLength = prng.int31(gen, 1, math.min(2, length - somePos))
+      let somePos = prng.int32(gen, 0, length - 1)
+      let delLength = prng.int32(gen, 1, math.min(2, length - somePos))
       if (prng.bool(gen)) {
-        var type = yarray.get(somePos)
-        if (type.length > 0) {
-          somePos = prng.int31(gen, 0, type.length - 1)
-          delLength = prng.int31(gen, 0, math.min(2, type.length - somePos))
+        const type = yarray.get(somePos)
+        if (type instanceof Y.Array && type.length > 0) {
+          somePos = prng.int32(gen, 0, type.length - 1)
+          delLength = prng.int32(gen, 0, math.min(2, type.length - somePos))
           type.delete(somePos, delLength)
         }
       } else {
+        const oldContent = yarray.toArray()
         yarray.delete(somePos, delLength)
+        oldContent.splice(somePos, delLength)
+        t.compareArrays(yarray.toArray(), oldContent)
       }
     }
   }
@@ -381,8 +530,8 @@ const arrayTransactions = [
 /**
  * @param {t.TestCase} tc
  */
-export const testRepeatGeneratingYarrayTests4 = tc => {
-  applyRandomTests(tc, arrayTransactions, 4)
+export const testRepeatGeneratingYarrayTests6 = tc => {
+  applyRandomTests(tc, arrayTransactions, 6)
 }
 
 /**

tests/y-map.tests.js

@@ -5,8 +5,35 @@ import {
 } from '../src/internals.js'
 
 import * as Y from '../src/index.js'
-import * as t from 'lib0/testing.js'
-import * as prng from 'lib0/prng.js'
+import * as t from 'lib0/testing'
+import * as prng from 'lib0/prng'
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testMapHavingIterableAsConstructorParamTests = tc => {
+  const { map0 } = init(tc, { users: 1 })
+
+  const m1 = new Y.Map(Object.entries({ number: 1, string: 'hello' }))
+  map0.set('m1', m1)
+  t.assert(m1.get('number') === 1)
+  t.assert(m1.get('string') === 'hello')
+
+  const m2 = new Y.Map([
+    ['object', { x: 1 }],
+    ['boolean', true]
+  ])
+  map0.set('m2', m2)
+  t.assert(m2.get('object').x === 1)
+  t.assert(m2.get('boolean') === true)
+
+  const m3 = new Y.Map([...m1, ...m2])
+  map0.set('m3', m3)
+  t.assert(m3.get('number') === 1)
+  t.assert(m3.get('string') === 'hello')
+  t.assert(m3.get('object').x === 1)
+  t.assert(m3.get('boolean') === true)
+}
 
 /**
  * @param {t.TestCase} tc
@@ -15,6 +42,7 @@ export const testBasicMapTests = tc => {
   const { testConnector, users, map0, map1, map2 } = init(tc, { users: 3 })
   users[2].disconnect()
 
+  map0.set('null', null)
   map0.set('number', 1)
   map0.set('string', 'hello Y')
   map0.set('object', { key: { key2: 'value' } })
@@ -27,24 +55,29 @@ export const testBasicMapTests = tc => {
   array.insert(0, [0])
   array.insert(0, [-1])
 
+  t.assert(map0.get('null') === null, 'client 0 computed the change (null)')
   t.assert(map0.get('number') === 1, 'client 0 computed the change (number)')
   t.assert(map0.get('string') === 'hello Y', 'client 0 computed the change (string)')
   t.assert(map0.get('boolean0') === false, 'client 0 computed the change (boolean)')
   t.assert(map0.get('boolean1') === true, 'client 0 computed the change (boolean)')
   t.compare(map0.get('object'), { key: { key2: 'value' } }, 'client 0 computed the change (object)')
   t.assert(map0.get('y-map').get('y-array').get(0) === -1, 'client 0 computed the change (type)')
+  t.assert(map0.size === 7, 'client 0 map has correct size')
 
   users[2].connect()
   testConnector.flushAllMessages()
 
+  t.assert(map1.get('null') === null, 'client 1 received the update (null)')
   t.assert(map1.get('number') === 1, 'client 1 received the update (number)')
   t.assert(map1.get('string') === 'hello Y', 'client 1 received the update (string)')
   t.assert(map1.get('boolean0') === false, 'client 1 computed the change (boolean)')
   t.assert(map1.get('boolean1') === true, 'client 1 computed the change (boolean)')
   t.compare(map1.get('object'), { key: { key2: 'value' } }, 'client 1 received the update (object)')
   t.assert(map1.get('y-map').get('y-array').get(0) === -1, 'client 1 received the update (type)')
+  t.assert(map1.size === 7, 'client 1 map has correct size')
 
   // compare disconnected user
+  t.assert(map2.get('null') === null, 'client 2 received the update (null) - was disconnected')
   t.assert(map2.get('number') === 1, 'client 2 received the update (number) - was disconnected')
   t.assert(map2.get('string') === 'hello Y', 'client 2 received the update (string) - was disconnected')
   t.assert(map2.get('boolean0') === false, 'client 2 computed the change (boolean)')
@@ -109,7 +142,7 @@ export const testGetAndSetOfMapPropertySyncs = tc => {
   t.compare(map0.get('stuff'), 'stuffy')
   testConnector.flushAllMessages()
   for (const user of users) {
-    var u = user.getMap('map')
+    const u = user.getMap('map')
     t.compare(u.get('stuff'), 'stuffy')
   }
   compare(users)
@@ -124,12 +157,26 @@ export const testGetAndSetOfMapPropertyWithConflict = tc => {
   map1.set('stuff', 'c1')
   testConnector.flushAllMessages()
   for (const user of users) {
-    var u = user.getMap('map')
+    const u = user.getMap('map')
     t.compare(u.get('stuff'), 'c1')
   }
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSizeAndDeleteOfMapProperty = tc => {
+  const { map0 } = init(tc, { users: 1 })
+  map0.set('stuff', 'c0')
+  map0.set('otherstuff', 'c1')
+  t.assert(map0.size === 2, `map size is ${map0.size} expected 2`)
+  map0.delete('stuff')
+  t.assert(map0.size === 1, `map size after delete is ${map0.size}, expected 1`)
+  map0.delete('otherstuff')
+  t.assert(map0.size === 0, `map size after delete is ${map0.size}, expected 0`)
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -140,12 +187,55 @@ export const testGetAndSetAndDeleteOfMapProperty = tc => {
   map1.delete('stuff')
   testConnector.flushAllMessages()
   for (const user of users) {
-    var u = user.getMap('map')
+    const u = user.getMap('map')
     t.assert(u.get('stuff') === undefined)
   }
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSetAndClearOfMapProperties = tc => {
+  const { testConnector, users, map0 } = init(tc, { users: 1 })
+  map0.set('stuff', 'c0')
+  map0.set('otherstuff', 'c1')
+  map0.clear()
+  testConnector.flushAllMessages()
+  for (const user of users) {
+    const u = user.getMap('map')
+    t.assert(u.get('stuff') === undefined)
+    t.assert(u.get('otherstuff') === undefined)
+    t.assert(u.size === 0, `map size after clear is ${u.size}, expected 0`)
+  }
+  compare(users)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSetAndClearOfMapPropertiesWithConflicts = tc => {
+  const { testConnector, users, map0, map1, map2, map3 } = init(tc, { users: 4 })
+  map0.set('stuff', 'c0')
+  map1.set('stuff', 'c1')
+  map1.set('stuff', 'c2')
+  map2.set('stuff', 'c3')
+  testConnector.flushAllMessages()
+  map0.set('otherstuff', 'c0')
+  map1.set('otherstuff', 'c1')
+  map2.set('otherstuff', 'c2')
+  map3.set('otherstuff', 'c3')
+  map3.clear()
+  testConnector.flushAllMessages()
+  for (const user of users) {
+    const u = user.getMap('map')
+    t.assert(u.get('stuff') === undefined)
+    t.assert(u.get('otherstuff') === undefined)
+    t.assert(u.size === 0, `map size after clear is ${u.size}, expected 0`)
+  }
+  compare(users)
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -157,7 +247,7 @@ export const testGetAndSetOfMapPropertyWithThreeConflicts = tc => {
   map2.set('stuff', 'c3')
   testConnector.flushAllMessages()
   for (const user of users) {
-    var u = user.getMap('map')
+    const u = user.getMap('map')
     t.compare(u.get('stuff'), 'c3')
   }
   compare(users)
@@ -180,7 +270,7 @@ export const testGetAndSetAndDeleteOfMapPropertyWithThreeConflicts = tc => {
   map3.delete('stuff')
   testConnector.flushAllMessages()
   for (const user of users) {
-    var u = user.getMap('map')
+    const u = user.getMap('map')
     t.assert(u.get('stuff') === undefined)
   }
   compare(users)
@@ -253,7 +343,7 @@ export const testObserversUsingObservedeep = tc => {
  * @param {Object<string,any>} should
  */
 const compareEvent = (is, should) => {
-  for (var key in should) {
+  for (const key in should) {
     t.compare(should[key], is[key])
   }
 }
@@ -292,6 +382,30 @@ export const testThrowsAddAndUpdateAndDeleteEvents = tc => {
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testThrowsDeleteEventsOnClear = tc => {
+  const { users, map0 } = init(tc, { users: 2 })
+  /**
+   * @type {Object<string,any>}
+   */
+  let event = {}
+  map0.observe(e => {
+    event = e // just put it on event, should be thrown synchronously anyway
+  })
+  // set values
+  map0.set('stuff', 4)
+  map0.set('otherstuff', new Y.Array())
+  // clear
+  map0.clear()
+  compareEvent(event, {
+    keysChanged: new Set(['stuff', 'otherstuff']),
+    target: map0
+  })
+  compare(users)
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -341,9 +455,9 @@ export const testChangeEvent = tc => {
 }
 
 /**
- * @param {t.TestCase} tc
+ * @param {t.TestCase} _tc
  */
-export const testYmapEventExceptionsShouldCompleteTransaction = tc => {
+export const testYmapEventExceptionsShouldCompleteTransaction = _tc => {
   const doc = new Y.Doc()
   const map = doc.getMap('map')
 
@@ -431,12 +545,12 @@ export const testYmapEventHasCorrectValueWhenSettingAPrimitiveFromOtherUser = tc
 const mapTransactions = [
   function set (user, gen) {
     const key = prng.oneOf(gen, ['one', 'two'])
-    var value = prng.utf16String(gen)
+    const value = prng.utf16String(gen)
     user.getMap('map').set(key, value)
   },
   function setType (user, gen) {
     const key = prng.oneOf(gen, ['one', 'two'])
-    var type = prng.oneOf(gen, [new Y.Array(), new Y.Map()])
+    const type = prng.oneOf(gen, [new Y.Array(), new Y.Map()])
     user.getMap('map').set(key, type)
     if (type instanceof Y.Array) {
       type.insert(0, [1, 2, 3, 4])
@@ -454,7 +568,7 @@ const mapTransactions = [
  * @param {t.TestCase} tc
  */
 export const testRepeatGeneratingYmapTests10 = tc => {
-  applyRandomTests(tc, mapTransactions, 10)
+  applyRandomTests(tc, mapTransactions, 3)
 }
 
 /**

tests/y-xml.tests.js

@@ -1,7 +1,7 @@
 import { init, compare } from './testHelper.js'
 import * as Y from '../src/index.js'
 
-import * as t from 'lib0/testing.js'
+import * as t from 'lib0/testing'
 
 /**
  * @param {t.TestCase} tc
@@ -15,6 +15,23 @@ export const testSetProperty = tc => {
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testHasProperty = tc => {
+  const { testConnector, users, xml0, xml1 } = init(tc, { users: 2 })
+  xml0.setAttribute('height', '10')
+  t.assert(xml0.hasAttribute('height'), 'Simple set+has works')
+  testConnector.flushAllMessages()
+  t.assert(xml1.hasAttribute('height'), 'Simple set+has works (remote)')
+
+  xml0.removeAttribute('height')
+  t.assert(!xml0.hasAttribute('height'), 'Simple set+remove+has works')
+  testConnector.flushAllMessages()
+  t.assert(!xml1.hasAttribute('height'), 'Simple set+remove+has works (remote)')
+  compare(users)
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -73,3 +90,96 @@ export const testTreewalker = tc => {
   t.assert(xml0.querySelector('p') === paragraph1, 'querySelector found paragraph1')
   compare(users)
 }
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testYtextAttributes = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = /** @type {Y.XmlText} */ (ydoc.get('', Y.XmlText))
+  ytext.observe(event => {
+    t.compare(event.changes.keys.get('test'), { action: 'add', oldValue: undefined })
+  })
+  ytext.setAttribute('test', 42)
+  t.compare(ytext.getAttribute('test'), 42)
+  t.compare(ytext.getAttributes(), { test: 42 })
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSiblings = tc => {
+  const ydoc = new Y.Doc()
+  const yxml = ydoc.getXmlFragment()
+  const first = new Y.XmlText()
+  const second = new Y.XmlElement('p')
+  yxml.insert(0, [first, second])
+  t.assert(first.nextSibling === second)
+  t.assert(second.prevSibling === first)
+  t.assert(first.parent === yxml)
+  t.assert(yxml.parent === null)
+  t.assert(yxml.firstChild === first)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testInsertafter = tc => {
+  const ydoc = new Y.Doc()
+  const yxml = ydoc.getXmlFragment()
+  const first = new Y.XmlText()
+  const second = new Y.XmlElement('p')
+  const third = new Y.XmlElement('p')
+
+  const deepsecond1 = new Y.XmlElement('span')
+  const deepsecond2 = new Y.XmlText()
+  second.insertAfter(null, [deepsecond1])
+  second.insertAfter(deepsecond1, [deepsecond2])
+
+  yxml.insertAfter(null, [first, second])
+  yxml.insertAfter(second, [third])
+
+  t.assert(yxml.length === 3)
+  t.assert(second.get(0) === deepsecond1)
+  t.assert(second.get(1) === deepsecond2)
+
+  t.compareArrays(yxml.toArray(), [first, second, third])
+
+  t.fails(() => {
+    const el = new Y.XmlElement('p')
+    el.insertAfter(deepsecond1, [new Y.XmlText()])
+  })
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testClone = tc => {
+  const ydoc = new Y.Doc()
+  const yxml = ydoc.getXmlFragment()
+  const first = new Y.XmlText('text')
+  const second = new Y.XmlElement('p')
+  const third = new Y.XmlElement('p')
+  yxml.push([first, second, third])
+  t.compareArrays(yxml.toArray(), [first, second, third])
+
+  const cloneYxml = yxml.clone()
+  ydoc.getArray('copyarr').insert(0, [cloneYxml])
+  t.assert(cloneYxml.length === 3)
+  t.compare(cloneYxml.toJSON(), yxml.toJSON())
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testFormattingBug = tc => {
+  const ydoc = new Y.Doc()
+  const yxml = /** @type {Y.XmlText} */ (ydoc.get('', Y.XmlText))
+  const delta = [
+    { insert: 'A', attributes: { em: {}, strong: {} } },
+    { insert: 'B', attributes: { em: {} } },
+    { insert: 'C', attributes: { em: {}, strong: {} } }
+  ]
+  yxml.applyDelta(delta)
+  t.compare(yxml.toDelta(), delta)
+}