13.0.6

remove deadlinks

.github/FUNDING.yml

@@ -0,0 +1,12 @@
+# 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/nodejs.yml

@@ -0,0 +1,31 @@
+# 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: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [10.x, 12.x, 13.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 lint
+    - run: npm run test-extensive
+      env:
+        CI: true

.jsdoc.json

@@ -17,7 +17,7 @@
     "useCollapsibles": true,
     "collapse": true,
     "resources": {
-      "y-js.org": "yjs.website"
+      "yjs.dev": "Yjs website"
     },
     "logo": {
       "url": "https://user-images.githubusercontent.com/5553757/48975307-61efb100-f06d-11e8-9177-ee895e5916e5.png",

.markdownlint.json

@@ -0,0 +1,4 @@
+{
+  "default": true,
+  "no-inline-html": false
+}

README.v13.md

@@ -1,559 +0,0 @@
-# ![Yjs](https://user-images.githubusercontent.com/5553757/48975307-61efb100-f06d-11e8-9177-ee895e5916e5.png)
-> A CRDT framework with a powerful abstraction of shared data
-
-Yjs is a [CRDT implementation](#Yjs-CRDT-Algorithm) that exposes its internal data structure as *shared types*. Shared types are common data types like `Map` or `Array` with superpowers: changes are automatically distributed to other peers and merged without merge conflicts.
-
-Yjs is **network agnostic** (p2p!), supports many existing **rich text editors**, **offline editing**, **version snapshots**, **undo/redo** and **shared cursors**. It scales well with an unlimited number of users and is well suited for even large documents.
-
-* Chat: [https://gitter.im/y-js/yjs](https://gitter.im/y-js/yjs)
-* Demos: [https://github.com/y-js/yjs-demos](https://github.com/y-js/yjs-demos)
-* Benchmarks: [https://github.com/dmonad/crdt-benchmarks](https://github.com/dmonad/crdt-benchmarks)
-
-# Table of Contents
-
-* [Overview](#Overview)
-  * [Bindings](#Bindings)
-  * [Providers](#Providers)
-* [Getting Started](#Getting-Started)
-* [API](#API)
-  * [Shared Types](#Shared-Types)
-  * [Y.Doc](#Y.Doc)
-  * [Document Updates](#Document-Updates)
-  * [Relative Positions](#Relative-Positions)
-* [Miscellaneous](#Miscellaneous)
-  * [Typescript Declarations](#Typescript-Declarations)
-* [Yjs CRDT Algorithm](#Yjs-CRDT-Algorithm)
-* [Evaluation](#Evaluation)
-  * [Existing shared editing libraries](#Exisisting-Javascript-Libraries)
-  * [CRDT Algorithms](#CRDT-Algorithms)
-  * [Comparison of CRDT with OT](#Comparing-CRDT-with-OT)
-  * [Comparison of CRDT Algorithms](#Comparing-CRDT-Algorithms)
-  * [Comparison of Yjs with other Implementations](#Comparing-Yjs-with-other-Implementations)
-* [License and Author](#License-and-Author)
-
-
-## Overview
-
-This repository contains a collection of shared types that can be observed for changes and manipulated concurrently. Network functionality and two-way-bindings are implemented in separate modules.
-
-### Bindings
-
-| Name                                                   | Cursors | Binding |  Demo |
-|---|:-:|---|---|
-| [ProseMirror](https://prosemirror.net/) | ✔ | [y-prosemirror](http://github.com/y-js/y-prosemirror) | [demo](https://yjs-demos.now.sh/prosemirror/) |
-| [Quill](https://quilljs.com/) |  | [y-quill](http://github.com/y-js/y-quill) | [demo](https://yjs-demos.now.sh/quill/) |
-| [CodeMirror](https://codemirror.net/) | ✔ | [y-codemirror](http://github.com/y-js/y-codemirror) | [demo](https://yjs-demos.now.sh/codemirror/) |
-| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](http://github.com/y-js/y-monaco) | [demo](https://yjs-demos.now.sh/monaco/) |
-| [Ace](https://ace.c9.io/) | | [y-ace](http://github.com/y-js/y-ace) | [demo](https://yjs-demos.now.sh/ace/) |
-| [Textarea](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/textarea) | | [y-textarea](http://github.com/y-js/y-textarea) | [demo](https://yjs-demos.now.sh/textarea/) |
-| [DOM](https://developer.mozilla.org/en-US/docs/Web/API/Document_Object_Model) | | [y-dom](http://github.com/y-js/y-dom) | [demo](https://yjs-demos.now.sh/dom/) |
-
-
-### Providers
-
-Setting up the communication between clients, managing awareness information, and storing shared data for offline usage is quite a hassle. **Providers** manage all that for you and are the perfect starting point for your collaborative app.
-
-<dl>
-  <dt><a href="http://github.com/y-js/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/y-js/y-mesh">y-mesh</a></dt>
-  <dd>[WIP] Creates a connected graph of webrtc connections with a high <a href="https://en.wikipedia.org/wiki/Strength_of_a_graph">strength</a>. It requires a signalling server that connects a client to the first peer. But after that the network manages itself. It is well suited for large and small networks.</dd>
-  <dt><a href="http://github.com/y-js/y-dat">y-dat</a></dt>
-  <dd>[WIP] Write document updates effinciently 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>
-</dl>
-
-## Getting Started
-
-Install Yjs and a provider with your favorite package manager.
-
-```sh
-npm i yjs@13.0.0-82 y-websocket@1.0.0-3 y-textarea
-```
-
-**Start the y-websocket server**
-
-```sh
-PORT=1234 node ./node_modules/y-websocket/bin/server.js
-```
-
-**Example: Textarea Binding**
-
-This is a complete example on how to create a connection to a [y-websocket](https://github.com/y-js/y-websocket) server instance, sync the shared document to all clients in a *room*, and bind a Y.Text type to a dom textarea. All changes to the textarea are automatically shared with everyone in the same room.
-
-```js
-import * as Y from 'yjs'
-import { WebsocketProvider } from 'y-websocket'
-import { TextareaBinding } from 'y-textarea'
-
-const doc = Y.Doc()
-const provider = new WebsocketProvider('http://localhost:1234', 'roomname')
-// sync all document updates through the websocket connection
-provider.sync('doc')
-
-// Define a shared type on the document.
-const ytext = doc.getText('my resume')
-
-// use data bindings to bind types to editors
-const binding = new TextareaBinding(ytext, document.querySelector('textarea'))
-```
-
-**Example: Observe types**
-
-```js
-const yarray = doc.getArray('my-array')
-yarray.observe(event => {
-  console.log('yarray was modified')
-})
-// every time a local or remote client modifies yarray, the observer is called
-yarray.insert(0, ['val']) // => "yarray was modified"
-```
-
-**Example: Nest types**
-
-Remember, shared types are just plain old data types. The only limitation is that a shared type must exist only once in the shared document.
-
-```js
-const ymap = doc.getMap('map')
-const foodArray = new Y.Array()
-foodArray.insert(0, ['apple', 'banana'])
-ymap.set('food', foodArray)
-ymap.get('food') === foodArray // => true
-ymap.set('fruit', foodArray) // => Error! foodArray is already defined on the shared document
-```
-
-Now you understand how types are defined on a shared document. Next you can jump to the [demo repository](https://github.com/y-js/yjs-demos) or continue reading the API docs.
-
-## API
-
-```js
-import * as Y from 'yjs'
-```
-
-### Shared Types
-
-<details>
-  <summary><b>Y.Array</b></summary>
-  <br>
-  <p>
-    A shareable Array-like type that supports efficient insert/delete of elements at any position. Internally it uses a linked list of Arrays that is split when 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>
-    <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 position 0.
-    </dd>
-    <b><code>push(Array&lt;Object|boolean|Array|string|number|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>length:number</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>
-    <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>
-    <dd>Copies the content of this YArray to a new Array. It transforms all child types to JSON using their <code>toJSON</code> method.</dd>
-    <b><code>[Symbol.Iterator]</code></b>
-    <dd>
-      Returns an YArray Iterator that contains the values for each index in the array.
-      <pre>for (let value of yarray) { .. }</pre>
-    </dd>
-    <b><code>observe(function(YArrayEvent, Transaction):void)</code></b>
-    <dd>
-      Adds an event listener to this type that will be called synchronously every time this type is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns.
-    </dd>
-    <b><code>unobserve(function(YArrayEvent, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observe</code> event listener from this type.
-    </dd>
-    <b><code>observeDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Adds an event listener to this type that will be called synchronously every time this type or any of its children is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns. The event listener receives all Events created by itself or any of its children.
-    </dd>
-    <b><code>unobserveDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observeDeep</code> event listener from this type.
-    </dd>
-  </dl>
-</details>
-<details>
-  <summary><b>Y.Map</b></summary>
-  <br>
-  <p>
-    A shareable Map type.
-  </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>
-    <dd></dd>
-    <b><code>set(key:string, value:object|boolean|string|number|Uint8Array|Y.Type)</code></b>
-    <dd></dd>
-    <b><code>delete(key:string)</code></b>
-    <dd></dd>
-    <b><code>has(key:string):boolean</code></b>
-    <dd></dd>
-    <b><code>get(index:number)</code></b>
-    <dd></dd>
-    <b><code>toJSON():Object&lt;string, Object|boolean|Array|string|number&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>[Symbol.Iterator]</code></b>
-    <dd>
-      Returns an Iterator of <code>[key, value]</code> pairs.
-      <pre>for (let [key, value] of ymap) { .. }</pre>
-    </dd>
-    <b><code>entries()</code></b>
-    <dd>
-      Returns an Iterator of <code>[key, value]</code> pairs.
-    </dd>
-    <b><code>values()</code></b>
-    <dd>
-      Returns an Iterator of all values.
-    </dd>
-    <b><code>keys()</code></b>
-    <dd>
-      Returns an Iterator of all keys.
-    </dd>
-    <b><code>observe(function(YMapEvent, Transaction):void)</code></b>
-    <dd>
-      Adds an event listener to this type that will be called synchronously every time this type is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns.
-    </dd>
-    <b><code>unobserve(function(YMapEvent, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observe</code> event listener from this type.
-    </dd>
-    <b><code>observeDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Adds an event listener to this type that will be called synchronously every time this type or any of its children is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns. The event listener receives all Events created by itself or any of its children.
-    </dd>
-    <b><code>unobserveDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observeDeep</code> event listener from this type.
-    </dd>
-  </dl>
-</details>
-
-<details>
-  <summary><b>Y.Text</b></summary>
-  <br>
-  <p>
-    A shareable type that is optimized for shared editing on text. It allows to assign properties to ranges in the text. This makes it possible to implement rich-text bindings to this type.
-  </p>
-  <p>
-    This type can also be transformed to the <a href="https://quilljs.com/docs/delta">delta format</a>. Similarly the YTextEvents compute changes as deltas.
-  </p>
-  <pre>const ytext = new Y.Text()</pre>
-  <dl>
-    <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.
-      <pre>ytext.insert(0, 'bold text', { bold: true })</pre>
-    </dd>
-    <b><code>delete(index:number, length:number)</code></b>
-    <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>length:number</code></b>
-    <dd></dd>
-    <b><code>toString():string</code></b>
-    <dd>Transforms this type, without formatting options, into a string.</dd>
-    <b><code>toJSON():string</code></b>
-    <dd>See <code>toString</code></dd>
-    <b><code>toDelta():Delta</code></b>
-    <dd>Transforms this type to a <a href="https://quilljs.com/docs/delta/">Quill Delta</a></dd>
-    <b><code>observe(function(YTextEvent, Transaction):void)</code></b>
-    <dd>
-      Adds an event listener to this type that will be called synchronously every time this type is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns.
-    </dd>
-    <b><code>unobserve(function(YTextEvent, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observe</code> event listener from this type.
-    </dd>
-    <b><code>observeDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Adds an event listener to this type that will be called synchronously every time this type or any of its children is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns. The event listener receives all Events created by itself or any of its children.
-    </dd>
-    <b><code>unobserveDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observeDeep</code> event listener from this type.
-    </dd>
-  </dl>
-</details>
-
-<details>
-  <summary><b>YXmlFragment</b></summary>
-  <br>
-  <p>
-    A container that holds an Array of Y.XmlElements.
-  </p>
-  <pre><code>const yxml = new Y.XmlFragment()</code></pre>
-  <dl>
-    <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>length:number</code></b>
-    <dd></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>
-    <dd>Transforms this type and all children to new DOM elements.</dd>
-    <b><code>toString():string</code></b>
-    <dd>Get the XML serialization of all descendants.</dd>
-    <b><code>toJSON():string</code></b>
-    <dd>See <code>toString</code>.</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 this type is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns.
-    </dd>
-    <b><code>unobserve(function(YXmlEvent, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observe</code> event listener from this type.
-    </dd>
-    <b><code>observeDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Adds an event listener to this type that will be called synchronously every time this type or any of its children is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns. The event listener receives all Events created by itself or any of its children.
-    </dd>
-    <b><code>unobserveDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observeDeep</code> event listener from this type.
-    </dd>
-  </dl>
-</details>
-
-<details>
-  <summary><b>Y.XmlElement</b></summary>
-  <br>
-  <p>
-    A shareable type that represents an XML Element. It has a <code>nodeName</code>, attributes, and a list of children. But it makes no effort to validate its content and be actually XML compliant.
-  </p>
-  <pre><code>const yxml = new Y.XmlElement()</code></pre>
-  <dl>
-    <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>length:number</code></b>
-    <dd></dd>
-    <b><code>setAttribute(attributeName:string, attributeValue:string)</code></b>
-    <dd></dd>
-    <b><code>removeAttribute(attributeName:string)</code></b>
-    <dd></dd>
-    <b><code>getAttribute(attributeName:string):string</code></b>
-    <dd></dd>
-    <b><code>getAttributes(attributeName:string):Object&lt;string,string&gt;</code></b>
-    <dd></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>
-    <dd>Transforms this type and all children to a new DOM element.</dd>
-    <b><code>toString():string</code></b>
-    <dd>Get the XML serialization of all descendants.</dd>
-    <b><code>toJSON():string</code></b>
-    <dd>See <code>toString</code>.</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 this type is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns.
-    </dd>
-    <b><code>unobserve(function(YXmlEvent, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observe</code> event listener from this type.
-    </dd>
-    <b><code>observeDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Adds an event listener to this type that will be called synchronously every time this type or any of its children is modified. In the case this type is modified in the event listener, the event listener will be called again after the current event listener returns. The event listener receives all Events created by itself or any of its children.
-    </dd>
-    <b><code>unobserveDeep(function(Array&lt;YEvent&gt;, Transaction):void)</code></b>
-    <dd>
-      Removes an <code>observeDeep</code> event listener from this type.
-    </dd>
-  </dl>
-</details>
-
-### Y.Doc
-
-```js
-const doc = new Y.Doc()
-```
-
-<dl>
-  <b><code>clientID</code></b>
-  <dd>A unique id that identifies this client. (readonly)</dd>
-  <b><code>transact(function(Transaction):void [, origin:any])</code></b>
-  <dd>Every change on the shared document happens in a transaction. Observer calls and the <code>update</code> event are called after each transaction. You should <i>bundle</i> changes into a single transaction to reduce the amount of event 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>get(string, Y.[TypeClass]):[Type]</code></b>
-  <dd>Define a shared type.</dd>
-  <b><code>getArray(string):Y.Array</code></b>
-  <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>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>
-  <dd>Register an event listener on the shared type</dd>
-  <b><code>off(string, function)</code></b>
-  <dd>Unregister an event listener from the shared type</dd>
-</dl>
-
-
-#### Y.Doc Events
-<dl>
-  <b><code>on('update', function(updateMessage:Uint8Array, origin:any, Y.Doc):void)</code></b>
-  <dd>Listen to document updates. Document updates must be transmitted to all other peers. You can apply document updates in any order and multiple times.</dd>
-  <b><code>on('beforeTransaction', function(Y.Transaction, Y.Doc):void)</code></b>
-  <dd>Emitted before each transaction.</dd>
-  <b><code>on('afterTransaction', function(Y.Transaction, Y.Doc):void)</code></b>
-  <dd>Emitted after each transaction.</dd>
-</dl>
-
-### Document Updates
-
-Changes on the shared document are encoded into *document updates*. Document updates are *commutative* and *idempotent*. This means that they can be applied in any order and multiple times.
-
-**Example: Listen to update events and apply them on remote client**
-```js
-const doc1 = new Y.Doc()
-const doc2 = new Y.Doc()
-
-doc1.on('update', update => {
-  Y.applyUpdate(doc2, update)
-})
-
-doc2.on('update', update => {
-  Y.applyUpdate(doc1, update)
-})
-
-// All changes are also applied to the other document
-doc1.getArray('myarray').insert(0, ['Hello doc2, you got this?'])
-doc2.getArray('myarray').get(0) // => 'Hello doc2, you got this?'
-```
-
-Yjs internally maintains a [state vector](#State-Vector) that denotes the next expected clock from each client. In a different interpretation it holds the number of structs created by each client. When two clients sync, you can either exchange the complete document structure or only the differences by sending the state vector to compute the differences.
-
-**Example: Sync two clients by exchanging the complete document structure**
-
-```js
-const state1 = Y.encodeStateAsUpdate(ydoc1)
-const state2 = Y.encodeStateAsUpdate(ydoc2)
-Y.applyUpdate(ydoc1, state2)
-Y.applyUpdate(ydoc2, state1)
-```
-
-**Example: Sync two clients by computing the differences**
-
-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.
-
-```js
-const stateVector1 = Y.encodeStateVector(ydoc1)
-const stateVector2 = Y.encodeStateVector(ydoc2)
-const diff1 = Y.encodeStateAsUpdate(ydoc1, stateVector2)
-const diff2 = Y.encodeStateAsUpdate(ydoc2, stateVector1)
-Y.applyUpdate(ydoc1, diff2)
-Y.applyUpdate(ydoc2, diff1)
-```
-
-<dl>
-  <b><code>Y.applyUpdate(Y.Doc, update:Uint8Array, [transactionOrigin:any])</code></b>
-  <dd>Apply a document update on the shared document. Optionally you can specify <code>transactionOrigin</code> that will be stored on <code>transaction.origin</code> and <code>ydoc.on('update', (update, origin) => ..)</code>.</dd>
-  <b><code>Y.encodeStateAsUpdate(Y.Doc, [encodedTargetStateVector:Uint8Array]):Uint8Array</code></b>
-  <dd>Encode the document state as a single update message that can be applied on the remote document. Optionally specify the target state vector to only write the 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>
-</dl>
-
-### Relative Positions
-> This API is not stable yet
-
-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.
-
-**Example: Transform to RelativePosition and back**
-```js
-const relPos = Y.createRelativePositionFromTypeIndex(ytext, 2)
-const pos = Y.createAbsolutePositionFromRelativePosition(relPos, doc)
-pos.type === ytext // => true
-pos.index === 2 // => true
-```
-
-**Example: Send relative position to remote client (json)**
-```js
-const relPos = Y.createRelativePositionFromTypeIndex(ytext, 2)
-const encodedRelPos = JSON.stringify(relPos)
-// send encodedRelPos to remote client..
-const parsedRelPos = JSON.parse(encodedRelPos)
-const pos = Y.createAbsolutePositionFromRelativePosition(parsedRelPos, remoteDoc)
-pos.type === remoteytext // => true
-pos.index === 2 // => true
-```
-
-**Example: Send relative position to remote client (Uint8Array)**
-```js
-const relPos = Y.createRelativePositionFromTypeIndex(ytext, 2)
-const encodedRelPos = Y.encodeRelativePosition(relPos)
-// send encodedRelPos to remote client..
-const parsedRelPos = Y.decodeRelativePosition(encodedRelPos)
-const pos = Y.createAbsolutePositionFromRelativePosition(parsedRelPos, remoteDoc)
-pos.type === remoteytext // => true
-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.decodeRelativePosition(Uint8Array):RelativePosition</code></b>
-  <dd></dd>
-</dl>
-
-## 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 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 shared editing on text. OT approaches that support shared editing without a central source of truth (a central server) require too much bookkeeping to be viable in practice. CRDTs are better suited for distributed systems, provide additional guarantees that the document can be synced with remote clients, and 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.
-
-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).
-
-**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 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'}]`.
-2. When a struct that contains content (e.g. `ItemString`) is deleted, the struct will be replaced with an `ItemDeleted` that does not contain content anymore.
-3. When a type is deleted, all child elements are transformed to `GC` structs. A `GC` struct only denotes the existence of a struct and that it is deleted. `GC` structs can always be merged with other `GC` structs if the id's are adjacent.
-
-Especially when working on structured content (e.g. shared editing on ProseMirror), these improvements yield very good results when [benchmarking](https://github.com/dmonad/crdt-benchmarks) random document edits. In practice they show even better results, because users usually edit text in sequence, resulting in structs that can easily be merged. The benchmarks show that even in the worst case scenario that a user edits text from right to left, Yjs achieves good performance even for huge documents.
-
-#### State Vector
-Yjs has the ability to exchange only the differences when syncing two clients. We use lamport timestamps to identify structs and to track in which order a client created them. Each struct has an `struct.id = { client: number, clock: number}` that uniquely identifies a struct. We define the next expected `clock` by each client as the *state vector*. This data structure is similar to the [version vectors](https://en.wikipedia.org/wiki/Version_vector) data structure. But we use state vectors only to describe the state of the local document, so we can compute the missing struct of the remote client. We do not use it to track causality.
-
-## License and Author
-
-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.

package.json

@@ -1,23 +1,23 @@
 {
   "name": "yjs",
-  "version": "13.0.0-85",
+  "version": "13.0.6",
   "description": "Shared Editing Library",
-  "main": "./dist/yjs.js",
+  "main": "./dist/yjs.cjs",
   "module": "./dist/yjs.mjs",
+  "types": "./dist/src/index.d.ts",
   "sideEffects": false,
   "scripts": {
-    "test": "npm run dist && PRODUCTION=1 node ./dist/tests.js --repitition-time 50 --production",
-    "test-exhaustive": "npm run lint && npm run dist && node ./dist/tests.js --repitition-time 10000",
-    "dist": "rm -rf dist && rollup -c",
+    "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",
+    "dist": "rm -rf dist && rollup -c && tsc",
     "watch": "rollup -wc",
-    "lint": "standard && tsc",
-    "docs": "rm -rf docs; jsdoc --configure ./.jsdoc.json --verbose --readme ./README.v13.md --package ./package.json || true",
-    "serve-docs": "npm run docs && serve ./docs/",
-    "preversion": "PRODUCTION=1 npm run dist && npm run docs && node ./dist/tests.js --repitition-time 1000",
-    "postversion": "git push && git push --tags",
-    "debug": "concurrently 'live-server --port=3443 --entry-file=test.html' 'npm run watch'",
-    "trace-deopt": "clear && rollup -c  && node --trace-deopt dist/test.js",
-    "trace-opt": "clear && rollup -c  && node --trace-opt dist/test.js"
+    "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",
+    "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"
   },
   "files": [
     "dist/*",
@@ -38,33 +38,38 @@
   },
   "repository": {
     "type": "git",
-    "url": "https://github.com/y-js/yjs.git"
+    "url": "https://github.com/yjs/yjs.git"
   },
   "keywords": [
-    "crdt"
+    "Yjs",
+    "CRDT",
+    "offline",
+    "shared editing",
+    "concurrency",
+    "collaboration"
   ],
   "author": "Kevin Jahns",
-  "email": "kevin.jahns@rwth-aachen.de",
+  "email": "kevin.jahns@protonmail.com",
   "license": "MIT",
   "bugs": {
-    "url": "https://github.com/y-js/yjs/issues"
+    "url": "https://github.com/yjs/yjs/issues"
   },
-  "homepage": "http://y-js.org",
+  "homepage": "https://yjs.dev",
   "dependencies": {
-    "lib0": "0.0.5"
+    "lib0": "^0.2.26"
   },
   "devDependencies": {
+    "@rollup/plugin-commonjs": "^11.0.1",
+    "@rollup/plugin-node-resolve": "^7.0.0",
     "concurrently": "^3.6.1",
-    "jsdoc": "^3.6.2",
-    "live-server": "^1.2.1",
-    "rollup": "^1.11.3",
+    "http-server": "^0.12.1",
+    "jsdoc": "^3.6.3",
+    "markdownlint-cli": "^0.19.0",
+    "rollup": "^1.30.0",
     "rollup-cli": "^1.0.9",
-    "rollup-plugin-commonjs": "^9.3.4",
-    "rollup-plugin-node-resolve": "^4.2.4",
-    "rollup-plugin-terser": "^4.0.4",
-    "standard": "^11.0.1",
+    "standard": "^14.0.0",
     "tui-jsdoc-template": "^1.2.2",
-    "typescript": "^3.4.5",
-    "y-protocols": "0.0.6"
+    "typescript": "^3.7.5",
+    "y-protocols": "^0.2.3"
   }
 }

rollup.config.js

@@ -1,6 +1,7 @@
-import nodeResolve from 'rollup-plugin-node-resolve'
-import commonjs from 'rollup-plugin-commonjs'
-import { terser } from 'rollup-plugin-terser'
+import nodeResolve from '@rollup/plugin-node-resolve'
+import commonjs from '@rollup/plugin-commonjs'
+
+const localImports = process.env.LOCALIMPORTS
 
 const customModules = new Set([
   'y-websocket',
@@ -23,52 +24,41 @@ const debugResolve = {
     if (importee === 'yjs') {
       return `${process.cwd()}/src/index.js`
     }
-    /*
-    if (customModules.has(importee.split('/')[0])) {
-      return `${process.cwd()}/../${importee}/src/${importee}.js`
+    if (localImports) {
+      if (customModules.has(importee.split('/')[0])) {
+        return `${process.cwd()}/../${importee}/src/${importee}.js`
+      }
+      if (customLibModules.has(importee.split('/')[0])) {
+        return `${process.cwd()}/../${importee}`
+      }
     }
-    if (customLibModules.has(importee.split('/')[0])) {
-      return `${process.cwd()}/../${importee}`
-    }
-    */
     return null
   }
 }
 
-const minificationPlugins = process.env.PRODUCTION ? [terser({
-  module: true,
-  compress: {
-    hoist_vars: true,
-    module: true,
-    passes: 5,
-    pure_getters: true,
-    unsafe_comps: true,
-    unsafe_undefined: true
-  },
-  mangle: {
-    toplevel: true
-  }
-})] : []
-
 export default [{
   input: './src/index.js',
-  output: [{
+  output: {
     name: 'Y',
-    file: 'dist/yjs.js',
+    file: 'dist/yjs.cjs',
     format: 'cjs',
     sourcemap: true,
     paths: path => {
       if (/^lib0\//.test(path)) {
-        return `lib0/dist/${path.slice(5)}`
+        return `lib0/dist/${path.slice(5, -3)}.cjs`
       }
       return path
     }
-  }, {
+  },
+  external: id => /^lib0\//.test(id)
+}, {
+  input: './src/index.js',
+  output: {
     name: 'Y',
     file: 'dist/yjs.mjs',
-    format: 'es',
+    format: 'esm',
     sourcemap: true
-  }],
+  },
   external: id => /^lib0\//.test(id)
 }, {
   input: './tests/index.js',
@@ -81,9 +71,24 @@ export default [{
   plugins: [
     debugResolve,
     nodeResolve({
-      sourcemap: true,
       mainFields: ['module', 'browser', 'main']
-    })
-    // commonjs()
+    }),
+    commonjs()
   ]
+}, {
+  input: './tests/index.js',
+  output: {
+    name: 'test',
+    file: 'dist/tests.cjs',
+    format: 'cjs',
+    sourcemap: true
+  },
+  plugins: [
+    debugResolve,
+    nodeResolve({
+      mainFields: ['module', 'main']
+    }),
+    commonjs()
+  ],
+  external: ['isomorphic.js']
 }]

src/index.js

@@ -13,16 +13,17 @@ export {
   YMapEvent,
   YArrayEvent,
   YEvent,
-  AbstractItem,
+  Item,
   AbstractStruct,
   GC,
-  ItemBinary,
-  ItemDeleted,
-  ItemEmbed,
-  ItemFormat,
-  ItemJSON,
-  ItemString,
-  ItemType,
+  ContentBinary,
+  ContentDeleted,
+  ContentEmbed,
+  ContentFormat,
+  ContentJSON,
+  ContentAny,
+  ContentString,
+  ContentType,
   AbstractType,
   RelativePosition,
   createRelativePositionFromTypeIndex,
@@ -36,11 +37,26 @@ export {
   compareIDs,
   getState,
   Snapshot,
+  createSnapshot,
+  createDeleteSet,
+  createDeleteSetFromStructStore,
+  snapshot,
+  emptySnapshot,
   findRootTypeKey,
   typeListToArraySnapshot,
   typeMapGetSnapshot,
   iterateDeletedStructs,
   applyUpdate,
+  readUpdate,
   encodeStateAsUpdate,
-  encodeStateVector
+  encodeStateVector,
+  UndoManager,
+  decodeSnapshot,
+  encodeSnapshot,
+  isDeleted,
+  isParentOf,
+  equalSnapshots,
+  PermanentUserData, // @TODO experimental
+  tryGc,
+  transact
 } from './internals.js'

src/internals.js

@@ -1,13 +1,16 @@
+
 export * from './utils/DeleteSet.js'
+export * from './utils/Doc.js'
+export * from './utils/encoding.js'
 export * from './utils/EventHandler.js'
 export * from './utils/ID.js'
 export * from './utils/isParentOf.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/Doc.js'
+export * from './utils/UndoManager.js'
 export * from './utils/YEvent.js'
 
 export * from './types/AbstractType.js'
@@ -21,14 +24,13 @@ export * from './types/YXmlHook.js'
 export * from './types/YXmlText.js'
 
 export * from './structs/AbstractStruct.js'
-export * from './structs/AbstractItem.js'
 export * from './structs/GC.js'
-export * from './structs/ItemBinary.js'
-export * from './structs/ItemDeleted.js'
-export * from './structs/ItemEmbed.js'
-export * from './structs/ItemFormat.js'
-export * from './structs/ItemJSON.js'
-export * from './structs/ItemString.js'
-export * from './structs/ItemType.js'
-
-export * from './utils/encoding.js'
+export * from './structs/ContentBinary.js'
+export * from './structs/ContentDeleted.js'
+export * from './structs/ContentEmbed.js'
+export * from './structs/ContentFormat.js'
+export * from './structs/ContentJSON.js'
+export * from './structs/ContentAny.js'
+export * from './structs/ContentString.js'
+export * from './structs/ContentType.js'
+export * from './structs/Item.js'

src/structs/AbstractStruct.js

@@ -6,22 +6,22 @@ import {
 import * as encoding from 'lib0/encoding.js' // eslint-disable-line
 import * as error from 'lib0/error.js'
 
-/**
- * @private
- */
 export class AbstractStruct {
   /**
    * @param {ID} id
+   * @param {number} length
    */
-  constructor (id) {
+  constructor (id, length) {
     /**
      * The uniqe identifier of this struct.
      * @type {ID}
      * @readonly
      */
     this.id = id
+    this.length = length
     this.deleted = false
   }
+
   /**
    * Merge this struct with the item to the right.
    * This method is already assuming that `this.id.clock + this.length === this.id.clock`.
@@ -32,21 +32,16 @@ export class AbstractStruct {
   mergeWith (right) {
     return false
   }
-  /**
-   * @type {number}
-   */
-  get length () {
-    throw error.methodUnimplemented()
-  }
+
   /**
    * @param {encoding.Encoder} encoder The encoder to write data to.
    * @param {number} offset
    * @param {number} encodingRef
-   * @private
    */
   write (encoder, offset, encodingRef) {
     throw error.methodUnimplemented()
   }
+
   /**
    * @param {Transaction} transaction
    */
@@ -55,9 +50,6 @@ export class AbstractStruct {
   }
 }
 
-/**
- * @private
- */
 export class AbstractStructRef {
   /**
    * @param {ID} id
@@ -73,6 +65,7 @@ export class AbstractStructRef {
      */
     this.id = id
   }
+
   /**
    * @param {Transaction} transaction
    * @return {Array<ID|null>}
@@ -80,6 +73,7 @@ export class AbstractStructRef {
   getMissing (transaction) {
     return this._missing
   }
+
   /**
    * @param {Transaction} transaction
    * @param {StructStore} store
@@ -89,10 +83,4 @@ export class AbstractStructRef {
   toStruct (transaction, store, offset) {
     throw error.methodUnimplemented()
   }
-  /**
-   * @type {number}
-   */
-  get length () {
-    return 1
-  }
 }

src/structs/ContentAny.js

@@ -0,0 +1,111 @@
+import {
+  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
+   */
+  constructor (arr) {
+    /**
+     * @type {Array<any>}
+     */
+    this.arr = arr
+  }
+
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return this.arr.length
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return this.arr
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+
+  /**
+   * @return {ContentAny}
+   */
+  copy () {
+    return new ContentAny(this.arr)
+  }
+
+  /**
+   * @param {number} offset
+   * @return {ContentAny}
+   */
+  splice (offset) {
+    const right = new ContentAny(this.arr.slice(offset))
+    this.arr = this.arr.slice(0, offset)
+    return right
+  }
+
+  /**
+   * @param {ContentAny} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    this.arr = this.arr.concat(right.arr)
+    return true
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    const len = this.arr.length
+    encoding.writeVarUint(encoder, len - offset)
+    for (let i = offset; i < len; i++) {
+      const c = this.arr[i]
+      encoding.writeAny(encoder, c)
+    }
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 8
+  }
+}
+
+/**
+ * @param {decoding.Decoder} decoder
+ * @return {ContentAny}
+ */
+export const readContentAny = decoder => {
+  const len = decoding.readVarUint(decoder)
+  const cs = []
+  for (let i = 0; i < len; i++) {
+    cs.push(decoding.readAny(decoder))
+  }
+  return new ContentAny(cs)
+}

src/structs/ContentBinary.js

@@ -0,0 +1,95 @@
+import {
+  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'
+
+export class ContentBinary {
+  /**
+   * @param {Uint8Array} content
+   */
+  constructor (content) {
+    this.content = content
+  }
+
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return 1
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return [this.content]
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+
+  /**
+   * @return {ContentBinary}
+   */
+  copy () {
+    return new ContentBinary(this.content)
+  }
+
+  /**
+   * @param {number} offset
+   * @return {ContentBinary}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {ContentBinary} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    return false
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarUint8Array(encoder, this.content)
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 3
+  }
+}
+
+/**
+ * @param {decoding.Decoder} decoder
+ * @return {ContentBinary}
+ */
+export const readContentBinary = decoder => new ContentBinary(buffer.copyUint8Array(decoding.readVarUint8Array(decoder)))

src/structs/ContentDeleted.js

@@ -0,0 +1,104 @@
+
+import {
+  addToDeleteSet,
+  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
+   */
+  constructor (len) {
+    this.len = len
+  }
+
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return this.len
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return []
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return false
+  }
+
+  /**
+   * @return {ContentDeleted}
+   */
+  copy () {
+    return new ContentDeleted(this.len)
+  }
+
+  /**
+   * @param {number} offset
+   * @return {ContentDeleted}
+   */
+  splice (offset) {
+    const right = new ContentDeleted(this.len - offset)
+    this.len = offset
+    return right
+  }
+
+  /**
+   * @param {ContentDeleted} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    this.len += right.len
+    return true
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {
+    addToDeleteSet(transaction.deleteSet, item.id, this.len)
+    item.deleted = true
+  }
+
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarUint(encoder, this.len - offset)
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 1
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentDeleted}
+ */
+export const readContentDeleted = decoder => new ContentDeleted(decoding.readVarUint(decoder))

src/structs/ContentEmbed.js

@@ -0,0 +1,100 @@
+
+import {
+  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'
+
+/**
+ * @private
+ */
+export class ContentEmbed {
+  /**
+   * @param {Object} embed
+   */
+  constructor (embed) {
+    this.embed = embed
+  }
+
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return 1
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return [this.embed]
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+
+  /**
+   * @return {ContentEmbed}
+   */
+  copy () {
+    return new ContentEmbed(this.embed)
+  }
+
+  /**
+   * @param {number} offset
+   * @return {ContentEmbed}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {ContentEmbed} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    return false
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarString(encoder, JSON.stringify(this.embed))
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 5
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentEmbed}
+ */
+export const readContentEmbed = decoder => new ContentEmbed(JSON.parse(decoding.readVarString(decoder)))

src/structs/ContentFormat.js

@@ -0,0 +1,101 @@
+
+import {
+  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'
+
+/**
+ * @private
+ */
+export class ContentFormat {
+  /**
+   * @param {string} key
+   * @param {Object} value
+   */
+  constructor (key, value) {
+    this.key = key
+    this.value = value
+  }
+
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return 1
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return []
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return false
+  }
+
+  /**
+   * @return {ContentFormat}
+   */
+  copy () {
+    return new ContentFormat(this.key, this.value)
+  }
+
+  /**
+   * @param {number} offset
+   * @return {ContentFormat}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {ContentFormat} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    return false
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarString(encoder, this.key)
+    encoding.writeVarString(encoder, JSON.stringify(this.value))
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 6
+  }
+}
+
+/**
+ * @param {decoding.Decoder} decoder
+ * @return {ContentFormat}
+ */
+export const readContentFormat = decoder => new ContentFormat(decoding.readVarString(decoder), JSON.parse(decoding.readVarString(decoder)))

src/structs/ContentJSON.js

@@ -0,0 +1,121 @@
+import {
+  Transaction, Item, StructStore // eslint-disable-line
+} from '../internals.js'
+
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+
+/**
+ * @private
+ */
+export class ContentJSON {
+  /**
+   * @param {Array<any>} arr
+   */
+  constructor (arr) {
+    /**
+     * @type {Array<any>}
+     */
+    this.arr = arr
+  }
+
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return this.arr.length
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return this.arr
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+
+  /**
+   * @return {ContentJSON}
+   */
+  copy () {
+    return new ContentJSON(this.arr)
+  }
+
+  /**
+   * @param {number} offset
+   * @return {ContentJSON}
+   */
+  splice (offset) {
+    const right = new ContentJSON(this.arr.slice(offset))
+    this.arr = this.arr.slice(0, offset)
+    return right
+  }
+
+  /**
+   * @param {ContentJSON} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    this.arr = this.arr.concat(right.arr)
+    return true
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    const len = this.arr.length
+    encoding.writeVarUint(encoder, len - offset)
+    for (let i = offset; i < len; i++) {
+      const c = this.arr[i]
+      encoding.writeVarString(encoder, c === undefined ? 'undefined' : JSON.stringify(c))
+    }
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 2
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentJSON}
+ */
+export const readContentJSON = decoder => {
+  const len = decoding.readVarUint(decoder)
+  const cs = []
+  for (let i = 0; i < len; i++) {
+    const c = decoding.readVarString(decoder)
+    if (c === 'undefined') {
+      cs.push(undefined)
+    } else {
+      cs.push(JSON.parse(c))
+    }
+  }
+  return new ContentJSON(cs)
+}

src/structs/ContentString.js

@@ -0,0 +1,104 @@
+import {
+  Transaction, Item, StructStore // eslint-disable-line
+} from '../internals.js'
+
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+
+/**
+ * @private
+ */
+export class ContentString {
+  /**
+   * @param {string} str
+   */
+  constructor (str) {
+    /**
+     * @type {string}
+     */
+    this.str = str
+  }
+
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return this.str.length
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return this.str.split('')
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+
+  /**
+   * @return {ContentString}
+   */
+  copy () {
+    return new ContentString(this.str)
+  }
+
+  /**
+   * @param {number} offset
+   * @return {ContentString}
+   */
+  splice (offset) {
+    const right = new ContentString(this.str.slice(offset))
+    this.str = this.str.slice(0, offset)
+    return right
+  }
+
+  /**
+   * @param {ContentString} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    this.str += right.str
+    return true
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarString(encoder, offset === 0 ? this.str : this.str.slice(offset))
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 4
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentString}
+ */
+export const readContentString = decoder => new ContentString(decoding.readVarString(decoder))

src/structs/ContentType.js

@@ -0,0 +1,174 @@
+
+import {
+  readYArray,
+  readYMap,
+  readYText,
+  readYXmlElement,
+  readYXmlFragment,
+  readYXmlHook,
+  readYXmlText,
+  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'
+
+/**
+ * @type {Array<function(decoding.Decoder):AbstractType<any>>}
+ * @private
+ */
+export const typeRefs = [
+  readYArray,
+  readYMap,
+  readYText,
+  readYXmlElement,
+  readYXmlFragment,
+  readYXmlHook,
+  readYXmlText
+]
+
+export const YArrayRefID = 0
+export const YMapRefID = 1
+export const YTextRefID = 2
+export const YXmlElementRefID = 3
+export const YXmlFragmentRefID = 4
+export const YXmlHookRefID = 5
+export const YXmlTextRefID = 6
+
+/**
+ * @private
+ */
+export class ContentType {
+  /**
+   * @param {AbstractType<YEvent>} type
+   */
+  constructor (type) {
+    /**
+     * @type {AbstractType<any>}
+     */
+    this.type = type
+  }
+
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return 1
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return [this.type]
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+
+  /**
+   * @return {ContentType}
+   */
+  copy () {
+    return new ContentType(this.type._copy())
+  }
+
+  /**
+   * @param {number} offset
+   * @return {ContentType}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {ContentType} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    return false
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {
+    this.type._integrate(transaction.doc, item)
+  }
+
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {
+    let item = this.type._start
+    while (item !== null) {
+      if (!item.deleted) {
+        item.delete(transaction)
+      } else {
+        // Whis 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)
+      }
+      item = item.right
+    }
+    this.type._map.forEach(item => {
+      if (!item.deleted) {
+        item.delete(transaction)
+      } else {
+        // same as above
+        transaction._mergeStructs.add(item.id)
+      }
+    })
+    transaction.changed.delete(this.type)
+  }
+
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {
+    let item = this.type._start
+    while (item !== null) {
+      item.gc(store, true)
+      item = item.right
+    }
+    this.type._start = null
+    this.type._map.forEach(/** @param {Item | null} item */ (item) => {
+      while (item !== null) {
+        item.gc(store, true)
+        item = item.left
+      }
+    })
+    this.type._map = new Map()
+  }
+
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    this.type._write(encoder)
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 7
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentType}
+ */
+export const readContentType = decoder => new ContentType(typeRefs[decoding.readVarUint(decoder)](decoder))

src/structs/GC.js

@@ -21,26 +21,18 @@ export class GC extends AbstractStruct {
    * @param {number} length
    */
   constructor (id, length) {
-    super(id)
-    /**
-     * @type {number}
-     */
-    this._len = length
+    super(id, length)
     this.deleted = true
   }
 
-  get length () {
-    return this._len
-  }
-
   delete () {}
 
   /**
-   * @param {AbstractStruct} right
+   * @param {GC} right
    * @return {boolean}
    */
   mergeWith (right) {
-    this._len += right.length
+    this.length += right.length
     return true
   }
 
@@ -57,7 +49,7 @@ export class GC extends AbstractStruct {
    */
   write (encoder, offset) {
     encoding.writeUint8(encoder, structGCRefNumber)
-    encoding.writeVarUint(encoder, this._len - offset)
+    encoding.writeVarUint(encoder, this.length - offset)
   }
 }
 
@@ -75,16 +67,9 @@ export class GCRef extends AbstractStructRef {
     /**
      * @type {number}
      */
-    this._len = decoding.readVarUint(decoder)
-  }
-  get length () {
-    return this._len
-  }
-  missing () {
-    return [
-      createID(this.id.client, this.id.clock - 1)
-    ]
+    this.length = decoding.readVarUint(decoder)
   }
+
   /**
    * @param {Transaction} transaction
    * @param {StructStore} store
@@ -95,11 +80,11 @@ export class GCRef extends AbstractStructRef {
     if (offset > 0) {
       // @ts-ignore
       this.id = createID(this.id.client, this.id.clock + offset)
-      this._len = this._len - offset
+      this.length -= offset
     }
     return new GC(
       this.id,
-      this._len
+      this.length
     )
   }
 }

src/structs/Item.js

@@ -10,14 +10,21 @@ import {
   replaceStruct,
   addStruct,
   addToDeleteSet,
-  ItemDeleted,
   findRootTypeKey,
   compareIDs,
   getItem,
-  getItemType,
   getItemCleanEnd,
   getItemCleanStart,
-  YEvent, StructStore, ID, AbstractType, Transaction // eslint-disable-line
+  readContentDeleted,
+  readContentBinary,
+  readContentJSON,
+  readContentAny,
+  readContentString,
+  readContentEmbed,
+  readContentFormat,
+  readContentType,
+  addChangedTypeToTransaction,
+  ContentType, ContentDeleted, StructStore, ID, AbstractType, Transaction // eslint-disable-line
 } from '../internals.js'
 
 import * as error from 'lib0/error.js'
@@ -28,27 +35,54 @@ import * as set from 'lib0/set.js'
 import * as binary from 'lib0/binary.js'
 
 /**
- * @param {AbstractItem} left
- * @param {AbstractItem} right
- * @return {boolean} If true, right is removed from the linked list and should be discarded
+ * @todo This should return several items
+ *
+ * @param {StructStore} store
+ * @param {ID} id
+ * @return {{item:Item, diff:number}}
  */
-export const mergeItemWith = (left, right) => {
-  if (compareIDs(right.origin, left.lastId) && left.right === right && compareIDs(left.rightOrigin, right.rightOrigin)) {
-    left.right = right.right
-    if (left.right !== null) {
-      left.right.left = left
+export const followRedone = (store, id) => {
+  /**
+   * @type {ID|null}
+   */
+  let nextID = id
+  let diff = 0
+  let item
+  do {
+    if (diff > 0) {
+      nextID = createID(nextID.client, nextID.clock + diff)
     }
-    return true
+    item = getItem(store, nextID)
+    diff = nextID.clock - item.id.clock
+    nextID = item.redone
+  } while (nextID !== null && item instanceof Item)
+  return {
+    item, diff
+  }
+}
+
+/**
+ * Make sure that neither item nor any of its parents is ever deleted.
+ *
+ * This property does not persist when storing it into a database or when
+ * sending it to other peers
+ *
+ * @param {Item|null} item
+ * @param {boolean} keep
+ */
+export const keepItem = (item, keep) => {
+  while (item !== null && item.keep !== keep) {
+    item.keep = keep
+    item = item.parent._item
   }
-  return false
 }
 
 /**
  * Split leftItem into two items
  * @param {Transaction} transaction
- * @param {AbstractItem} leftItem
+ * @param {Item} leftItem
  * @param {number} diff
- * @return {AbstractItem}
+ * @return {Item}
  *
  * @function
  * @private
@@ -56,18 +90,25 @@ export const mergeItemWith = (left, right) => {
 export const splitItem = (transaction, leftItem, diff) => {
   const id = leftItem.id
   // create rightItem
-  const rightItem = leftItem.copy(
+  const rightItem = new Item(
     createID(id.client, id.clock + diff),
     leftItem,
     createID(id.client, id.clock + diff - 1),
     leftItem.right,
     leftItem.rightOrigin,
     leftItem.parent,
-    leftItem.parentSub
+    leftItem.parentSub,
+    leftItem.content.splice(diff)
   )
   if (leftItem.deleted) {
     rightItem.deleted = true
   }
+  if (leftItem.keep) {
+    rightItem.keep = true
+  }
+  if (leftItem.redone !== null) {
+    rightItem.redone = createID(leftItem.redone.client, leftItem.redone.clock + diff)
+  }
   // update left (do not set leftItem.rightOrigin as it will lead to problems when syncing)
   leftItem.right = rightItem
   // update right
@@ -80,24 +121,127 @@ export const splitItem = (transaction, leftItem, diff) => {
   if (rightItem.parentSub !== null && rightItem.right === null) {
     rightItem.parent._map.set(rightItem.parentSub, rightItem)
   }
+  leftItem.length = diff
   return rightItem
 }
 
+/**
+ * Redoes the effect of this operation.
+ *
+ * @param {Transaction} transaction The Yjs instance.
+ * @param {Item} item
+ * @param {Set<Item>} redoitems
+ *
+ * @return {Item|null}
+ *
+ * @private
+ */
+export const redoItem = (transaction, item, redoitems) => {
+  if (item.redone !== null) {
+    return getItemCleanStart(transaction, item.redone)
+  }
+  let parentItem = item.parent._item
+  /**
+   * @type {Item|null}
+   */
+  let left
+  /**
+   * @type {Item|null}
+   */
+  let right
+  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) {
+      /**
+       * @type {Item|null}
+       */
+      let leftTrace = left
+      // trace redone until parent matches
+      while (leftTrace !== null && leftTrace.parent._item !== parentItem) {
+        leftTrace = leftTrace.redone === null ? null : getItemCleanStart(transaction, leftTrace.redone)
+      }
+      if (leftTrace !== null && leftTrace.parent._item === parentItem) {
+        left = leftTrace
+        break
+      }
+      left = left.left
+    }
+    while (right !== null) {
+      /**
+       * @type {Item|null}
+       */
+      let rightTrace = right
+      // trace redone until parent matches
+      while (rightTrace !== null && rightTrace.parent._item !== parentItem) {
+        rightTrace = rightTrace.redone === null ? null : getItemCleanStart(transaction, rightTrace.redone)
+      }
+      if (rightTrace !== null && rightTrace.parent._item === parentItem) {
+        right = rightTrace
+        break
+      }
+      right = right.right
+    }
+  }
+  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,
+    item.parentSub,
+    item.content.copy()
+  )
+  item.redone = redoneItem.id
+  keepItem(redoneItem, true)
+  redoneItem.integrate(transaction)
+  return redoneItem
+}
+
 /**
  * Abstract class that represents any content.
  */
-export class AbstractItem extends AbstractStruct {
+export class Item extends AbstractStruct {
   /**
    * @param {ID} id
-   * @param {AbstractItem | null} left
+   * @param {Item | null} left
    * @param {ID | null} origin
-   * @param {AbstractItem | null} right
+   * @param {Item | null} right
    * @param {ID | null} rightOrigin
    * @param {AbstractType<any>} parent
    * @param {string | null} parentSub
+   * @param {AbstractContent} content
    */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub) {
-    super(id)
+  constructor (id, left, origin, right, rightOrigin, parent, parentSub, content) {
+    super(id, content.getLength())
     /**
      * The item that was originally to the left of this item.
      * @type {ID | null}
@@ -106,12 +250,12 @@ export class AbstractItem extends AbstractStruct {
     this.origin = origin
     /**
      * The item that is currently to the left of this item.
-     * @type {AbstractItem | null}
+     * @type {Item | null}
      */
     this.left = left
     /**
      * The item that is currently to the right of this item.
-     * @type {AbstractItem | null}
+     * @type {Item | null}
      */
     this.right = right
     /**
@@ -143,14 +287,23 @@ export class AbstractItem extends AbstractStruct {
     /**
      * If this type's effect is reundone this type refers to the type that undid
      * this operation.
-     * @type {AbstractItem | null}
+     * @type {ID | null}
      */
     this.redone = null
+    /**
+     * @type {AbstractContent}
+     */
+    this.content = content
+    this.length = content.getLength()
+    this.countable = content.isCountable()
+    /**
+     * If true, do not garbage collect this Item.
+     */
+    this.keep = false
   }
 
   /**
    * @param {Transaction} transaction
-   * @private
    */
   integrate (transaction) {
     const store = transaction.doc.store
@@ -159,7 +312,7 @@ export class AbstractItem extends AbstractStruct {
     const parentSub = this.parentSub
     const length = this.length
     /**
-     * @type {AbstractItem|null}
+     * @type {Item|null}
      */
     let o
     // set o to the first conflicting item
@@ -175,11 +328,11 @@ export class AbstractItem extends AbstractStruct {
     }
     // TODO: use something like DeleteSet here (a tree implementation would be best)
     /**
-     * @type {Set<AbstractItem>}
+     * @type {Set<Item>}
      */
     const conflictingItems = new Set()
     /**
-     * @type {Set<AbstractItem>}
+     * @type {Set<Item>}
      */
     const itemsBeforeOrigin = new Set()
     // Let c in conflictingItems, b in itemsBeforeOrigin
@@ -238,8 +391,9 @@ export class AbstractItem extends AbstractStruct {
       parent._length += length
     }
     addStruct(store, this)
-    maplib.setIfUndefined(transaction.changed, parent, set.create).add(parentSub)
-    // @ts-ignore
+    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)
@@ -248,7 +402,6 @@ export class AbstractItem extends AbstractStruct {
 
   /**
    * Returns the next non-deleted item
-   * @private
    */
   get next () {
     let n = this.right
@@ -260,7 +413,6 @@ export class AbstractItem extends AbstractStruct {
 
   /**
    * Returns the previous non-deleted item
-   * @private
    */
   get prev () {
     let n = this.left
@@ -270,84 +422,6 @@ export class AbstractItem extends AbstractStruct {
     return n
   }
 
-  /**
-   * Creates an Item with the same effect as this Item (without position effect)
-   *
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @return {AbstractItem}
-   *
-   * @private
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    throw error.methodUnimplemented()
-  }
-
-  /**
-   * Redoes the effect of this operation.
-   *
-   * @param {Transaction} transaction The Yjs instance.
-   * @param {Set<AbstractItem>} redoitems
-   *
-   * @private
-   */
-  redo (transaction, redoitems) {
-    if (this.redone !== null) {
-      return this.redone
-    }
-    /**
-     * @type {any}
-     */
-    let parent = this.parent
-    if (parent === null) {
-      return
-    }
-    let left, right
-    if (this.parentSub === null) {
-      // Is an array item. Insert at the old position
-      left = this.left
-      right = this
-    } else {
-      // Is a map item. Insert as current value
-      left = parent.type._map.get(this.parentSub)
-      right = null
-    }
-    // make sure that parent is redone
-    if (parent._deleted === true && parent.redone === null) {
-      // try to undo parent if it will be undone anyway
-      if (!redoitems.has(parent) || !parent.redo(transaction, redoitems)) {
-        return false
-      }
-    }
-    if (parent.redone !== null) {
-      while (parent.redone !== null) {
-        parent = parent.redone
-      }
-      // find next cloned_redo items
-      while (left !== null) {
-        if (left.redone !== null && left.redone.parent === parent) {
-          left = left.redone
-          break
-        }
-        left = left.left
-      }
-      while (right !== null) {
-        if (right.redone !== null && right.redone.parent === parent) {
-          right = right.redone
-        }
-        right = right.right
-      }
-    }
-    this.redone = this.copy(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, this.parentSub)
-    this.redone.integrate(transaction)
-    return true
-  }
-
   /**
    * Computes the last content address of this Item.
    */
@@ -356,44 +430,35 @@ export class AbstractItem extends AbstractStruct {
   }
 
   /**
-   * Computes the length of this Item.
+   * Try to merge two items
+   *
+   * @param {Item} right
+   * @return {boolean}
    */
-  get length () {
-    return 1
-  }
-
-  /**
-   * Should return false if this Item is some kind of meta information
-   * (e.g. format information).
-   *
-   * * Whether this Item should be addressable via `yarray.get(i)`
-   * * Whether this Item should be counted when computing yarray.length
-   */
-  get countable () {
-    return true
-  }
-
-  /**
-   * Do not call directly. Always split via StructStore!
-   *
-   * Splits this Item so that another Item can be inserted in-between.
-   * This must be overwritten if _length > 1
-   * Returns right part after split
-   *
-   * (see {@link ItemJSON}/{@link ItemString} for implementation)
-   *
-   * Does not integrate the struct, nor store it in struct store.
-   *
-   * This method should only be cally by StructStore.
-   *
-   * @param {Transaction} transaction
-   * @param {number} diff
-   * @return {AbstractItem}
-   *
-   * @private
-   */
-  splitAt (transaction, diff) {
-    throw error.methodUnimplemented()
+  mergeWith (right) {
+    if (
+      compareIDs(right.origin, this.lastId) &&
+      this.right === right &&
+      compareIDs(this.rightOrigin, right.rightOrigin) &&
+      this.id.client === right.id.client &&
+      this.id.clock + this.length === right.id.clock &&
+      this.deleted === right.deleted &&
+      this.redone === null &&
+      right.redone === null &&
+      this.content.constructor === right.content.constructor &&
+      this.content.mergeWith(right.content)
+    ) {
+      if (right.keep) {
+        this.keep = true
+      }
+      this.right = right.right
+      if (this.right !== null) {
+        this.right.left = this
+      }
+      this.length += right.length
+      return true
+    }
+    return false
   }
 
   /**
@@ -411,50 +476,24 @@ export class AbstractItem extends AbstractStruct {
       this.deleted = true
       addToDeleteSet(transaction.deleteSet, this.id, this.length)
       maplib.setIfUndefined(transaction.changed, parent, set.create).add(this.parentSub)
+      this.content.delete(transaction)
     }
   }
 
-  /**
-   * @param {StructStore} store
-   *
-   * @private
-   */
-  gcChildren (store) { }
-
   /**
    * @param {StructStore} store
    * @param {boolean} parentGCd
-   *
-   * @private
    */
   gc (store, parentGCd) {
     if (!this.deleted) {
       throw error.unexpectedCase()
     }
-    let r
+    this.content.gc(store)
     if (parentGCd) {
-      r = new GC(this.id, this.length)
+      replaceStruct(store, this, new GC(this.id, this.length))
     } else {
-      r = new ItemDeleted(this.id, this.left, this.origin, this.right, this.rightOrigin, this.parent, this.parentSub, this.length)
-      if (r.right !== null) {
-        r.right.left = r
-      } else if (r.parentSub !== null) {
-        r.parent._map.set(r.parentSub, r)
-      }
-      if (r.left !== null) {
-        r.left.right = r
-      } else if (r.parentSub === null) {
-        r.parent._start = r
-      }
+      this.content = new ContentDeleted(this.length)
     }
-    replaceStruct(store, this, r)
-  }
-
-  /**
-   * @return {Array<any>}
-   */
-  getContent () {
-    throw error.methodUnimplemented()
   }
 
   /**
@@ -465,15 +504,12 @@ export class AbstractItem extends AbstractStruct {
    *
    * @param {encoding.Encoder} encoder The encoder to write data to.
    * @param {number} offset
-   * @param {number} encodingRef
-   *
-   * @private
    */
-  write (encoder, offset, encodingRef) {
+  write (encoder, offset) {
     const origin = offset > 0 ? createID(this.id.client, this.id.clock + offset - 1) : this.origin
     const rightOrigin = this.rightOrigin
     const parentSub = this.parentSub
-    const info = (encodingRef & binary.BITS5) |
+    const info = (this.content.getRef() & binary.BITS5) |
       (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
@@ -489,26 +525,140 @@ export class AbstractItem extends AbstractStruct {
       if (parent._item === null) {
         // parent type on y._map
         // find the correct key
-        // @ts-ignore we know that y exists
         const ykey = findRootTypeKey(parent)
         encoding.writeVarUint(encoder, 1) // write parentYKey
         encoding.writeVarString(encoder, ykey)
       } else {
         encoding.writeVarUint(encoder, 0) // write parent id
-        // @ts-ignore _item is defined because parent is integrated
         writeID(encoder, parent._item.id)
       }
       if (parentSub !== null) {
         encoding.writeVarString(encoder, parentSub)
       }
     }
+    this.content.write(encoder, offset)
+  }
+}
+
+/**
+ * @param {decoding.Decoder} decoder
+ * @param {number} info
+ */
+const readItemContent = (decoder, info) => contentRefs[info & binary.BITS5](decoder)
+
+/**
+ * A lookup map for reading Item content.
+ *
+ * @type {Array<function(decoding.Decoder):AbstractContent>}
+ */
+export const contentRefs = [
+  () => { throw error.unexpectedCase() }, // GC is not ItemContent
+  readContentDeleted,
+  readContentJSON,
+  readContentBinary,
+  readContentString,
+  readContentEmbed,
+  readContentFormat,
+  readContentType,
+  readContentAny
+]
+
+/**
+ * Do not implement this class!
+ */
+export class AbstractContent {
+  /**
+   * @return {number}
+   */
+  getLength () {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * Should return false if this Item is some kind of meta information
+   * (e.g. format information).
+   *
+   * * Whether this Item should be addressable via `yarray.get(i)`
+   * * Whether this Item should be counted when computing yarray.length
+   *
+   * @return {boolean}
+   */
+  isCountable () {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @return {AbstractContent}
+   */
+  copy () {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {number} offset
+   * @return {AbstractContent}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {AbstractContent} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    throw error.methodUnimplemented()
+  }
+
+  /**
+   * @return {number}
+   */
+  getRef () {
+    throw error.methodUnimplemented()
   }
 }
 
 /**
  * @private
  */
-export class AbstractItemRef extends AbstractStructRef {
+export class ItemRef extends AbstractStructRef {
   /**
    * @param {decoding.Decoder} decoder
    * @param {ID} id
@@ -558,85 +708,71 @@ export class AbstractItemRef extends AbstractStructRef {
     if (this.parent !== null) {
       missing.push(this.parent)
     }
+    /**
+     * @type {AbstractContent}
+     */
+    this.content = readItemContent(decoder, info)
+    this.length = this.content.getLength()
   }
-}
 
-/**
- * @param {AbstractItemRef} item
- * @param {number} offset
- *
- * @function
- * @private
- */
-export const changeItemRefOffset = (item, offset) => {
-  item.id = createID(item.id.client, item.id.clock + offset)
-  item.left = createID(item.id.client, item.id.clock - 1)
-}
-
-export class ItemParams {
   /**
-   * @param {AbstractItem?} left
-   * @param {AbstractItem?} right
-   * @param {AbstractType<YEvent>?} parent
-   * @param {string|null} parentSub
+   * @param {Transaction} transaction
+   * @param {StructStore} store
+   * @param {number} offset
+   * @return {Item|GC}
    */
-  constructor (left, right, parent, parentSub) {
-    this.left = left
-    this.right = right
-    this.parent = parent
-    this.parentSub = parentSub
-  }
-}
+  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
+    }
 
-/**
- * Outsourcing some of the logic of computing the item params from a received struct.
- * If parent === null, it is expected to gc the read struct. Otherwise apply it.
- *
- * @param {Transaction} transaction
- * @param {StructStore} store
- * @param {ID|null} leftid
- * @param {ID|null} rightid
- * @param {ID|null} parentid
- * @param {string|null} parentSub
- * @param {string|null} parentYKey
- * @return {ItemParams}
- *
- * @private
- * @function
- */
-export const computeItemParams = (transaction, store, leftid, rightid, parentid, parentSub, parentYKey) => {
-  const left = leftid === null ? null : getItemCleanEnd(transaction, store, leftid)
-  const right = rightid === null ? null : getItemCleanStart(transaction, store, rightid)
-  let parent = null
-  if (parentid !== null) {
-    const parentItem = getItemType(store, parentid)
-    switch (parentItem.constructor) {
-      case ItemDeleted:
-      case GC:
-        break
-      default:
-        // 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 probably 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 = parentItem.type
-        }
+    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()
     }
-  } else if (parentYKey !== null) {
-    parent = transaction.doc.get(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
+      )
   }
-  return new ItemParams(left, right, parent, parentSub)
 }

src/structs/ItemBinary.js

@@ -1,99 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  GC,
-  StructStore, Transaction, AbstractType, ID // 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'
-
-/**
- * @private
- */
-export const structBinaryRefNumber = 1
-
-/**
- * @private
- */
-export class ItemBinary extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {Uint8Array} content
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, content) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this.content = content
-  }
-  getContent () {
-    return [this.content]
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemBinary(id, left, origin, right, rightOrigin, parent, parentSub, this.content)
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structBinaryRefNumber)
-    encoding.writeVarUint8Array(encoder, this.content)
-  }
-}
-
-/**
- * @private
- */
-export class ItemBinaryRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {Uint8Array}
-     */
-    this.content = buffer.copyUint8Array(decoding.readVarUint8Array(decoder))
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemBinary|GC}
-   */
-  toStruct (transaction, store, offset) {
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemBinary(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.content
-      )
-  }
-}

src/structs/ItemDeleted.js

@@ -1,155 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  changeItemRefOffset,
-  GC,
-  splitItem,
-  addToDeleteSet,
-  mergeItemWith,
-  StructStore, Transaction, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structDeletedRefNumber = 2
-
-/**
- * @private
- */
-export class ItemDeleted extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {number} length
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, length) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this._len = length
-    this.deleted = true
-  }
-  get length () {
-    return this._len
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemDeleted(id, left, origin, right, rightOrigin, parent, parentSub, this.length)
-  }
-  /**
-   * @param {Transaction} transaction
-   */
-  integrate (transaction) {
-    super.integrate(transaction)
-    addToDeleteSet(transaction.deleteSet, this.id, this.length)
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {number} diff
-   */
-  splitAt (transaction, diff) {
-    /**
-     * @type {ItemDeleted}
-     */
-    // @ts-ignore
-    const right = splitItem(transaction, this, diff)
-    right._len -= diff
-    this._len = diff
-    return right
-  }
-  /**
-   * @param {ItemDeleted} right
-   * @return {boolean}
-   */
-  mergeWith (right) {
-    if (mergeItemWith(this, right)) {
-      this._len += right._len
-      return true
-    }
-    return false
-  }
-
-  /**
-   * @param {StructStore} store
-   * @param {boolean} parentGCd
-   *
-   * @private
-   */
-  gc (store, parentGCd) {
-    if (parentGCd) {
-      super.gc(store, parentGCd)
-    }
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structDeletedRefNumber)
-    encoding.writeVarUint(encoder, this.length - offset)
-  }
-}
-
-/**
- * @private
- */
-export class ItemDeletedRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {number}
-     */
-    this.len = decoding.readVarUint(decoder)
-  }
-  get length () {
-    return this.len
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemDeleted|GC}
-   */
-  toStruct (transaction, store, offset) {
-    if (offset > 0) {
-      changeItemRefOffset(this, offset)
-      this.len = this.len - offset
-    }
-
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemDeleted(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.len
-      )
-  }
-}

src/structs/ItemEmbed.js

@@ -1,95 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  GC,
-  Transaction, StructStore, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structEmbedRefNumber = 3
-
-/**
- * @private
- */
-export class ItemEmbed extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {Object} embed
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, embed) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this.embed = embed
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemEmbed(id, left, origin, right, rightOrigin, parent, parentSub, this.embed)
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structEmbedRefNumber)
-    encoding.writeVarString(encoder, JSON.stringify(this.embed))
-  }
-}
-
-/**
- * @private
- */
-export class ItemEmbedRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {Object}
-     */
-    this.embed = JSON.parse(decoding.readVarString(decoder))
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemEmbed|GC}
-   */
-  toStruct (transaction, store, offset) {
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemEmbed(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.embed
-      )
-  }
-}

src/structs/ItemFormat.js

@@ -1,103 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  GC,
-  Transaction, StructStore, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structFormatRefNumber = 4
-
-/**
- * @private
- */
-export class ItemFormat extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {string} key
-   * @param {any} value
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, key, value) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this.key = key
-    this.value = value
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemFormat(id, left, origin, right, rightOrigin, parent, parentSub, this.key, this.value)
-  }
-  get countable () {
-    return false
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structFormatRefNumber)
-    encoding.writeVarString(encoder, this.key)
-    encoding.writeVarString(encoder, JSON.stringify(this.value))
-  }
-}
-
-/**
- * @private
- */
-export class ItemFormatRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {string}
-     */
-    this.key = decoding.readVarString(decoder)
-    this.value = JSON.parse(decoding.readVarString(decoder))
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemFormat|GC}
-   */
-  toStruct (transaction, store, offset) {
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemFormat(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.key,
-        this.value
-      )
-  }
-}

src/structs/ItemJSON.js

@@ -1,153 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  splitItem,
-  changeItemRefOffset,
-  GC,
-  mergeItemWith,
-  Transaction, StructStore, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structJSONRefNumber = 5
-
-/**
- * @private
- */
-export class ItemJSON extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {Array<any>} content
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, content) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    /**
-     * @type {Array<any>}
-     */
-    this.content = content
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemJSON(id, left, origin, right, rightOrigin, parent, parentSub, this.content)
-  }
-  get length () {
-    return this.content.length
-  }
-  getContent () {
-    return this.content
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {number} diff
-   */
-  splitAt (transaction, diff) {
-    /**
-     * @type {ItemJSON}
-     */
-    // @ts-ignore
-    const right = splitItem(transaction, this, diff)
-    right.content = this.content.splice(diff)
-    return right
-  }
-  /**
-   * @param {ItemJSON} right
-   * @return {boolean}
-   */
-  mergeWith (right) {
-    if (mergeItemWith(this, right)) {
-      this.content = this.content.concat(right.content)
-      return true
-    }
-    return false
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structJSONRefNumber)
-    const len = this.content.length
-    encoding.writeVarUint(encoder, len - offset)
-    for (let i = offset; i < len; i++) {
-      const c = this.content[i]
-      encoding.writeVarString(encoder, c === undefined ? 'undefined' : JSON.stringify(c))
-    }
-  }
-}
-
-/**
- * @private
- */
-export class ItemJSONRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    const len = decoding.readVarUint(decoder)
-    const cs = []
-    for (let i = 0; i < len; i++) {
-      const c = decoding.readVarString(decoder)
-      if (c === 'undefined') {
-        cs.push(undefined)
-      } else {
-        cs.push(JSON.parse(c))
-      }
-    }
-    /**
-     * @type {Array<any>}
-     */
-    this.content = cs
-  }
-  get length () {
-    return this.content.length
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemJSON|GC}
-   */
-  toStruct (transaction, store, offset) {
-    if (offset > 0) {
-      changeItemRefOffset(this, offset)
-      this.content = this.content.slice(offset)
-    }
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemJSON(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.content
-      )
-  }
-}

src/structs/ItemString.js

@@ -1,138 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  splitItem,
-  changeItemRefOffset,
-  GC,
-  mergeItemWith,
-  Transaction, StructStore, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-export const structStringRefNumber = 6
-
-/**
- * @private
- */
-export class ItemString extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {string} string
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, string) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    /**
-     * @type {string}
-     */
-    this.string = string
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemString(id, left, origin, right, rightOrigin, parent, parentSub, this.string)
-  }
-  getContent () {
-    return this.string.split('')
-  }
-  get length () {
-    return this.string.length
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {number} diff
-   * @return {ItemString}
-   */
-  splitAt (transaction, diff) {
-    /**
-     * @type {ItemString}
-     */
-    // @ts-ignore
-    const right = splitItem(transaction, this, diff)
-    right.string = this.string.slice(diff)
-    this.string = this.string.slice(0, diff)
-    return right
-  }
-  /**
-   * @param {ItemString} right
-   * @return {boolean}
-   */
-  mergeWith (right) {
-    if (mergeItemWith(this, right)) {
-      this.string += right.string
-      return true
-    }
-    return false
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structStringRefNumber)
-    encoding.writeVarString(encoder, offset === 0 ? this.string : this.string.slice(offset))
-  }
-}
-
-/**
- * @private
- */
-export class ItemStringRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {string}
-     */
-    this.string = decoding.readVarString(decoder)
-  }
-  get length () {
-    return this.string.length
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemString|GC}
-   */
-  toStruct (transaction, store, offset) {
-    if (offset > 0) {
-      changeItemRefOffset(this, offset)
-      this.string = this.string.slice(offset)
-    }
-
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemString(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.string
-      )
-  }
-}

src/structs/ItemType.js

@@ -1,199 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  readYArray,
-  readYMap,
-  readYText,
-  readYXmlElement,
-  readYXmlFragment,
-  readYXmlHook,
-  readYXmlText,
-  StructStore, GC, Transaction, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js' // eslint-disable-line
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structTypeRefNumber = 7
-
-/**
- * @type {Array<function(decoding.Decoder):AbstractType<any>>}
- * @private
- */
-export const typeRefs = [
-  readYArray,
-  readYMap,
-  readYText,
-  readYXmlElement,
-  readYXmlFragment,
-  readYXmlHook,
-  readYXmlText
-]
-
-export const YArrayRefID = 0
-export const YMapRefID = 1
-export const YTextRefID = 2
-export const YXmlElementRefID = 3
-export const YXmlFragmentRefID = 4
-export const YXmlHookRefID = 5
-export const YXmlTextRefID = 6
-
-/**
- * @private
- */
-export class ItemType extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {AbstractType<any>} type
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, type) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this.type = type
-  }
-
-  getContent () {
-    return [this.type]
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @return {ItemType}
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemType(id, left, origin, right, rightOrigin, parent, parentSub, this.type._copy())
-  }
-  /**
-   * @param {Transaction} transaction
-   */
-  integrate (transaction) {
-    super.integrate(transaction)
-    this.type._integrate(transaction.doc, this)
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structTypeRefNumber)
-    this.type._write(encoder)
-  }
-  /**
-   * Mark this Item as deleted.
-   *
-   * @param {Transaction} transaction The Yjs instance
-   * @private
-   */
-  delete (transaction) {
-    if (!this.deleted) {
-      super.delete(transaction)
-      let item = this.type._start
-      while (item !== null) {
-        if (!item.deleted) {
-          item.delete(transaction)
-        } else {
-          // Whis 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)
-        }
-        item = item.right
-      }
-      this.type._map.forEach(item => {
-        if (!item.deleted) {
-          item.delete(transaction)
-        } else {
-          // same as above
-          transaction._mergeStructs.add(item.id)
-        }
-      })
-      transaction.changed.delete(this.type)
-      transaction.changedParentTypes.delete(this.type)
-    }
-  }
-
-  /**
-   * @param {StructStore} store
-   */
-  gcChildren (store) {
-    let item = this.type._start
-    while (item !== null) {
-      item.gc(store, true)
-      item = item.right
-    }
-    this.type._start = null
-    this.type._map.forEach(item => {
-      while (item !== null) {
-        item.gc(store, true)
-        // @ts-ignore
-        item = item.left
-      }
-    })
-    this._map = new Map()
-  }
-
-  /**
-   * @param {StructStore} store
-   * @param {boolean} parentGCd
-   */
-  gc (store, parentGCd) {
-    this.gcChildren(store)
-    super.gc(store, parentGCd)
-  }
-}
-
-/**
- * @private
- */
-export class ItemTypeRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    const typeRef = decoding.readVarUint(decoder)
-    /**
-     * @type {AbstractType<any>}
-     */
-    this.type = typeRefs[typeRef](decoder)
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemType|GC}
-   */
-  toStruct (transaction, store, offset) {
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemType(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.type
-      )
-  }
-}

src/types/AbstractType.js

@@ -4,14 +4,14 @@ import {
   callEventHandlerListeners,
   addEventHandlerListener,
   createEventHandler,
-  ItemType,
   nextID,
   isVisible,
-  ItemJSON,
-  ItemBinary,
+  ContentType,
+  ContentAny,
+  ContentBinary,
   createID,
   getItemCleanStart,
-  Doc, Snapshot, Transaction, EventHandler, YEvent, AbstractItem, // eslint-disable-line
+  Doc, Snapshot, Transaction, EventHandler, YEvent, Item, // eslint-disable-line
 } from '../internals.js'
 
 import * as map from 'lib0/map.js'
@@ -22,7 +22,6 @@ import * as encoding from 'lib0/encoding.js' // eslint-disable-line
 /**
  * Call event listeners with an event. This will also add an event to all
  * parents (for `.observeDeep` handlers).
- * @private
  *
  * @template EventType
  * @param {AbstractType<EventType>} type
@@ -30,7 +29,7 @@ import * as encoding from 'lib0/encoding.js' // eslint-disable-line
  * @param {EventType} event
  */
 export const callTypeObservers = (type, transaction, event) => {
-  callEventHandlerListeners(type._eH, event, transaction)
+  const changedType = type
   const changedParentTypes = transaction.changedParentTypes
   while (true) {
     // @ts-ignore
@@ -40,6 +39,7 @@ export const callTypeObservers = (type, transaction, event) => {
     }
     type = type._item.parent
   }
+  callEventHandlerListeners(changedType._eH, event, transaction)
 }
 
 /**
@@ -49,21 +49,18 @@ export const callTypeObservers = (type, transaction, event) => {
 export class AbstractType {
   constructor () {
     /**
-     * @type {ItemType|null}
+     * @type {Item|null}
      */
     this._item = null
     /**
-     * @private
-     * @type {Map<string,AbstractItem>}
+     * @type {Map<string,Item>}
      */
     this._map = new Map()
     /**
-     * @private
-     * @type {AbstractItem|null}
+     * @type {Item|null}
      */
     this._start = null
     /**
-     * @private
      * @type {Doc|null}
      */
     this.doc = null
@@ -88,8 +85,7 @@ export class AbstractType {
    * * Observer functions are fired
    *
    * @param {Doc} y The Yjs instance
-   * @param {ItemType|null} item
-   * @private
+   * @param {Item|null} item
    */
   _integrate (y, item) {
     this.doc = y
@@ -98,7 +94,6 @@ export class AbstractType {
 
   /**
    * @return {AbstractType<EventType>}
-   * @private
    */
   _copy () {
     throw error.methodUnimplemented()
@@ -106,7 +101,6 @@ export class AbstractType {
 
   /**
    * @param {encoding.Encoder} encoder
-   * @private
    */
   _write (encoder) { }
 
@@ -127,8 +121,6 @@ export class AbstractType {
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
-   *
-   * @private
    */
   _callObserver (transaction, parentSubs) { /* skip if no type is specified */ }
 
@@ -170,7 +162,7 @@ export class AbstractType {
 
   /**
    * @abstract
-   * @return {Object | Array | number | string}
+   * @return {any}
    */
   toJSON () {}
 }
@@ -187,7 +179,7 @@ export const typeListToArray = type => {
   let n = type._start
   while (n !== null) {
     if (n.countable && !n.deleted) {
-      const c = n.getContent()
+      const c = n.content.getContent()
       for (let i = 0; i < c.length; i++) {
         cs.push(c[i])
       }
@@ -210,7 +202,7 @@ export const typeListToArraySnapshot = (type, snapshot) => {
   let n = type._start
   while (n !== null) {
     if (n.countable && isVisible(n, snapshot)) {
-      const c = n.getContent()
+      const c = n.content.getContent()
       for (let i = 0; i < c.length; i++) {
         cs.push(c[i])
       }
@@ -234,7 +226,7 @@ export const typeListForEach = (type, f) => {
   let n = type._start
   while (n !== null) {
     if (n.countable && !n.deleted) {
-      const c = n.getContent()
+      const c = n.content.getContent()
       for (let i = 0; i < c.length; i++) {
         f(c[i], index++, type)
       }
@@ -287,18 +279,15 @@ export const typeListCreateIterator = type => {
         while (n !== null && n.deleted) {
           n = n.right
         }
-      }
-      // check if we reached the end, no need to check currentContent, because it does not exist
-      if (n === null) {
-        return {
-          done: true,
-          value: undefined
+        // check if we reached the end, no need to check currentContent, because it does not exist
+        if (n === null) {
+          return {
+            done: true,
+            value: undefined
+          }
         }
-      }
-      // currentContent could exist from the last iteration
-      if (currentContent === null) {
         // we found n, so we can set currentContent
-        currentContent = n.getContent()
+        currentContent = n.content.getContent()
         currentContentIndex = 0
         n = n.right // we used the content of n, now iterate to next
       }
@@ -331,7 +320,7 @@ export const typeListForEachSnapshot = (type, f, snapshot) => {
   let n = type._start
   while (n !== null) {
     if (n.countable && isVisible(n, snapshot)) {
-      const c = n.getContent()
+      const c = n.content.getContent()
       for (let i = 0; i < c.length; i++) {
         f(c[i], index++, type)
       }
@@ -352,7 +341,7 @@ export const typeListGet = (type, index) => {
   for (let n = type._start; n !== null; n = n.right) {
     if (!n.deleted && n.countable) {
       if (index < n.length) {
-        return n.getContent()[index]
+        return n.content.getContent()[index]
       }
       index -= n.length
     }
@@ -362,7 +351,7 @@ export const typeListGet = (type, index) => {
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem?} referenceItem
+ * @param {Item?} referenceItem
  * @param {Array<Object<string,any>|Array<any>|boolean|number|string|Uint8Array>} content
  *
  * @private
@@ -372,12 +361,12 @@ export const typeListInsertGenericsAfter = (transaction, parent, referenceItem,
   let left = referenceItem
   const right = referenceItem === null ? parent._start : referenceItem.right
   /**
-   * @type {Array<Object|Array|number>}
+   * @type {Array<Object|Array<any>|number>}
    */
   let jsonContent = []
   const packJsonContent = () => {
     if (jsonContent.length > 0) {
-      left = new ItemJSON(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, jsonContent)
+      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)
       jsonContent = []
     }
@@ -396,12 +385,12 @@ export const typeListInsertGenericsAfter = (transaction, parent, referenceItem,
         switch (c.constructor) {
           case Uint8Array:
           case ArrayBuffer:
-            left = new ItemBinary(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new Uint8Array(/** @type {Uint8Array} */ (c)))
+            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 ItemType(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, c)
+              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')
@@ -431,7 +420,7 @@ export const typeListInsertGenerics = (transaction, parent, index, content) => {
       if (index <= n.length) {
         if (index < n.length) {
           // insert in-between
-          getItemCleanStart(transaction, transaction.doc.store, createID(n.id.client, n.id.clock + index))
+          getItemCleanStart(transaction, createID(n.id.client, n.id.clock + index))
         }
         break
       }
@@ -457,7 +446,7 @@ export const typeListDelete = (transaction, parent, index, length) => {
   for (; n !== null && index > 0; n = n.right) {
     if (!n.deleted && n.countable) {
       if (index < n.length) {
-        getItemCleanStart(transaction, transaction.doc.store, createID(n.id.client, n.id.clock + index))
+        getItemCleanStart(transaction, createID(n.id.client, n.id.clock + index))
       }
       index -= n.length
     }
@@ -466,7 +455,7 @@ export const typeListDelete = (transaction, parent, index, length) => {
   while (length > 0 && n !== null) {
     if (!n.deleted) {
       if (length < n.length) {
-        getItemCleanStart(transaction, transaction.doc.store, createID(n.id.client, n.id.clock + length))
+        getItemCleanStart(transaction, createID(n.id.client, n.id.clock + length))
       }
       n.delete(transaction)
       length -= n.length
@@ -504,28 +493,30 @@ export const typeMapDelete = (transaction, parent, key) => {
  */
 export const typeMapSet = (transaction, parent, key, value) => {
   const left = parent._map.get(key) || null
+  let content
   if (value == null) {
-    new ItemJSON(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, [value]).integrate(transaction)
-    return
-  }
-  switch (value.constructor) {
-    case Number:
-    case Object:
-    case Boolean:
-    case Array:
-    case String:
-      new ItemJSON(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, [value]).integrate(transaction)
-      break
-    case Uint8Array:
-      new ItemBinary(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, value).integrate(transaction)
-      break
-    default:
-      if (value instanceof AbstractType) {
-        new ItemType(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, value).integrate(transaction)
-      } else {
-        throw new Error('Unexpected content type')
-      }
+    content = new ContentAny([value])
+  } else {
+    switch (value.constructor) {
+      case Number:
+      case Object:
+      case Boolean:
+      case Array:
+      case String:
+        content = new ContentAny([value])
+        break
+      case Uint8Array:
+        content = new ContentBinary(/** @type {Uint8Array} */ (value))
+        break
+      default:
+        if (value instanceof AbstractType) {
+          content = new ContentType(value)
+        } else {
+          throw new Error('Unexpected content type')
+        }
+    }
   }
+  new Item(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, content).integrate(transaction)
 }
 
 /**
@@ -538,7 +529,7 @@ export const typeMapSet = (transaction, parent, key, value) => {
  */
 export const typeMapGet = (parent, key) => {
   const val = parent._map.get(key)
-  return val !== undefined && !val.deleted ? val.getContent()[0] : undefined
+  return val !== undefined && !val.deleted ? val.content.getContent()[val.length - 1] : undefined
 }
 
 /**
@@ -552,10 +543,10 @@ export const typeMapGetAll = (parent) => {
   /**
    * @type {Object<string,any>}
    */
-  let res = {}
+  const res = {}
   for (const [key, value] of parent._map) {
     if (!value.deleted) {
-      res[key] = value.getContent()[value.length - 1]
+      res[key] = value.content.getContent()[value.length - 1]
     }
   }
   return res
@@ -585,14 +576,14 @@ export const typeMapHas = (parent, key) => {
  */
 export const typeMapGetSnapshot = (parent, key, snapshot) => {
   let v = parent._map.get(key) || null
-  while (v !== null && (!snapshot.sm.has(v.id.client) || v.id.clock >= (snapshot.sm.get(v.id.client) || 0))) {
+  while (v !== null && (!snapshot.sv.has(v.id.client) || v.id.clock >= (snapshot.sv.get(v.id.client) || 0))) {
     v = v.left
   }
-  return v !== null && isVisible(v, snapshot) ? v.getContent()[v.length - 1] : undefined
+  return v !== null && isVisible(v, snapshot) ? v.content.getContent()[v.length - 1] : undefined
 }
 
 /**
- * @param {Map<string,AbstractItem>} map
+ * @param {Map<string,Item>} map
  * @return {IterableIterator<Array<any>>}
  *
  * @private

src/types/YArray.js

@@ -15,7 +15,7 @@ import {
   YArrayRefID,
   callTypeObservers,
   transact,
-  Doc, Transaction, ItemType, // eslint-disable-line
+  Doc, Transaction, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as decoding from 'lib0/decoding.js' // eslint-disable-line
@@ -51,6 +51,7 @@ export class YArray extends AbstractType {
      */
     this._prelimContent = []
   }
+
   /**
    * Integrate this type into the Yjs instance.
    *
@@ -59,26 +60,27 @@ export class YArray extends AbstractType {
    * * Observer functions are fired
    *
    * @param {Doc} y The Yjs instance
-   * @param {ItemType} item
-   *
-   * @private
+   * @param {Item} item
    */
   _integrate (y, item) {
     super._integrate(y, item)
-    // @ts-ignore
-    this.insert(0, this._prelimContent)
+    this.insert(0, /** @type {Array<any>} */ (this._prelimContent))
     this._prelimContent = null
   }
+
+  _copy () {
+    return new YArray()
+  }
+
   get length () {
     return this._prelimContent === null ? this._length : this._prelimContent.length
   }
+
   /**
    * Creates YArrayEvent and calls observers.
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
-   *
-   * @private
    */
   _callObserver (transaction, parentSubs) {
     callTypeObservers(this, transaction, new YArrayEvent(this, transaction))
@@ -106,8 +108,7 @@ export class YArray extends AbstractType {
         typeListInsertGenerics(transaction, this, index, content)
       })
     } else {
-      // @ts-ignore _prelimContent is defined because this is not yet integrated
-      this._prelimContent.splice(index, 0, ...content)
+      /** @type {Array<any>} */ (this._prelimContent).splice(index, 0, ...content)
     }
   }
 
@@ -132,8 +133,7 @@ export class YArray extends AbstractType {
         typeListDelete(transaction, this, index, length)
       })
     } else {
-      // @ts-ignore _prelimContent is defined because this is not yet integrated
-      this._prelimContent.splice(index, length)
+      /** @type {Array<any>} */ (this._prelimContent).splice(index, length)
     }
   }
 
@@ -175,8 +175,7 @@ export class YArray extends AbstractType {
    *                 callback function
    */
   map (f) {
-    // @ts-ignore
-    return typeListMap(this, f)
+    return typeListMap(this, /** @type {any} */ (f))
   }
 
   /**
@@ -197,7 +196,6 @@ export class YArray extends AbstractType {
 
   /**
    * @param {encoding.Encoder} encoder
-   * @private
    */
   _write (encoder) {
     encoding.writeVarUint(encoder, YArrayRefID)

src/types/YMap.js

@@ -14,7 +14,7 @@ import {
   YMapRefID,
   callTypeObservers,
   transact,
-  Doc, Transaction, ItemType, // eslint-disable-line
+  Doc, Transaction, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -53,6 +53,7 @@ export class YMap extends AbstractType {
      */
     this._prelimContent = new Map()
   }
+
   /**
    * Integrate this type into the Yjs instance.
    *
@@ -61,25 +62,25 @@ export class YMap extends AbstractType {
    * * Observer functions are fired
    *
    * @param {Doc} y The Yjs instance
-   * @param {ItemType} item
-   *
-   * @private
+   * @param {Item} item
    */
   _integrate (y, item) {
     super._integrate(y, item)
-    // @ts-ignore
-    for (let [key, value] of this._prelimContent) {
+    for (const [key, value] of /** @type {Map<string, any>} */ (this._prelimContent)) {
       this.set(key, value)
     }
     this._prelimContent = null
   }
+
+  _copy () {
+    return new YMap()
+  }
+
   /**
    * Creates YMapEvent and calls observers.
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
-   *
-   * @private
    */
   _callObserver (transaction, parentSubs) {
     callTypeObservers(this, transaction, new YMapEvent(this, transaction, parentSubs))
@@ -95,9 +96,9 @@ export class YMap extends AbstractType {
      * @type {Object<string,T>}
      */
     const map = {}
-    for (let [key, item] of this._map) {
+    for (const [key, item] of this._map) {
       if (!item.deleted) {
-        const v = item.getContent()[0]
+        const v = item.content.getContent()[item.length - 1]
         map[key] = v instanceof AbstractType ? v.toJSON() : v
       }
     }
@@ -107,7 +108,7 @@ export class YMap extends AbstractType {
   /**
    * Returns the keys for each element in the YMap Type.
    *
-   * @return {Iterator<string>}
+   * @return {IterableIterator<string>}
    */
   keys () {
     return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => v[0])
@@ -116,10 +117,10 @@ export class YMap extends AbstractType {
   /**
    * Returns the keys for each element in the YMap Type.
    *
-   * @return {Iterator<string>}
+   * @return {IterableIterator<string>}
    */
   values () {
-    return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => v[1].getContent()[v[1].length - 1])
+    return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => v[1].content.getContent()[v[1].length - 1])
   }
 
   /**
@@ -128,7 +129,25 @@ export class YMap extends AbstractType {
    * @return {IterableIterator<any>}
    */
   entries () {
-    return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => [v[0], v[1].getContent()[v[1].length - 1]])
+    return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => [v[0], v[1].content.getContent()[v[1].length - 1]])
+  }
+
+  /**
+   * Executes a provided function on once on overy key-value pair.
+   *
+   * @param {function(T,string,YMap<T>):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) {
+      if (!item.deleted) {
+        f(item.content.getContent()[item.length - 1], key, this)
+      }
+    }
+    return map
   }
 
   /**
@@ -149,8 +168,7 @@ export class YMap extends AbstractType {
         typeMapDelete(transaction, this, key)
       })
     } else {
-      // @ts-ignore
-      this._prelimContent.delete(key)
+      /** @type {Map<string, any>} */ (this._prelimContent).delete(key)
     }
   }
 
@@ -166,8 +184,7 @@ export class YMap extends AbstractType {
         typeMapSet(transaction, this, key, value)
       })
     } else {
-      // @ts-ignore
-      this._prelimContent.set(key, value)
+      /** @type {Map<string, any>} */ (this._prelimContent).set(key, value)
     }
     return value
   }
@@ -179,8 +196,7 @@ export class YMap extends AbstractType {
    * @return {T|undefined}
    */
   get (key) {
-    // @ts-ignore
-    return typeMapGet(this, key)
+    return /** @type {any} */ (typeMapGet(this, key))
   }
 
   /**
@@ -195,8 +211,6 @@ export class YMap extends AbstractType {
 
   /**
    * @param {encoding.Encoder} encoder
-   *
-   * @private
    */
   _write (encoder) {
     encoding.writeVarUint(encoder, YMapRefID)

src/types/YText.js

@@ -5,9 +5,6 @@
 
 import {
   YEvent,
-  ItemEmbed,
-  ItemString,
-  ItemFormat,
   AbstractType,
   nextID,
   createID,
@@ -16,16 +13,28 @@ import {
   YTextRefID,
   callTypeObservers,
   transact,
-  Doc, ItemType, AbstractItem, Snapshot, StructStore, Transaction // eslint-disable-line
+  ContentEmbed,
+  ContentFormat,
+  ContentString,
+  splitSnapshotAffectedStructs,
+  ID, Doc, Item, Snapshot, Transaction // eslint-disable-line
 } from '../internals.js'
 
 import * as decoding from 'lib0/decoding.js' // eslint-disable-line
 import * as encoding from 'lib0/encoding.js'
+import * as object from 'lib0/object.js'
+
+/**
+ * @param {any} a
+ * @param {any} b
+ * @return {boolean}
+ */
+const equalAttrs = (a, b) => a === b || (typeof a === 'object' && typeof b === 'object' && a && b && object.equalFlat(a, b))
 
 export class ItemListPosition {
   /**
-   * @param {AbstractItem|null} left
-   * @param {AbstractItem|null} right
+   * @param {Item|null} left
+   * @param {Item|null} right
    */
   constructor (left, right) {
     this.left = left
@@ -35,8 +44,8 @@ export class ItemListPosition {
 
 export class ItemTextListPosition extends ItemListPosition {
   /**
-   * @param {AbstractItem|null} left
-   * @param {AbstractItem|null} right
+   * @param {Item|null} left
+   * @param {Item|null} right
    * @param {Map<string,any>} currentAttributes
    */
   constructor (left, right, currentAttributes) {
@@ -47,8 +56,8 @@ export class ItemTextListPosition extends ItemListPosition {
 
 export class ItemInsertionResult extends ItemListPosition {
   /**
-   * @param {AbstractItem|null} left
-   * @param {AbstractItem|null} right
+   * @param {Item|null} left
+   * @param {Item|null} right
    * @param {Map<string,any>} negatedAttributes
    */
   constructor (left, right, negatedAttributes) {
@@ -59,33 +68,31 @@ export class ItemInsertionResult extends ItemListPosition {
 
 /**
  * @param {Transaction} transaction
- * @param {StructStore} store
  * @param {Map<string,any>} currentAttributes
- * @param {AbstractItem|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} left
+ * @param {Item|null} right
  * @param {number} count
  * @return {ItemTextListPosition}
  *
  * @private
  * @function
  */
-const findNextPosition = (transaction, store, currentAttributes, left, right, count) => {
+const findNextPosition = (transaction, currentAttributes, left, right, count) => {
   while (right !== null && count > 0) {
-    switch (right.constructor) {
-      case ItemEmbed:
-      case ItemString:
+    switch (right.content.constructor) {
+      case ContentEmbed:
+      case ContentString:
         if (!right.deleted) {
           if (count < right.length) {
             // split right
-            getItemCleanStart(transaction, store, createID(right.id.client, right.id.clock + count))
+            getItemCleanStart(transaction, createID(right.id.client, right.id.clock + count))
           }
           count -= right.length
         }
         break
-      case ItemFormat:
+      case ContentFormat:
         if (!right.deleted) {
-          // @ts-ignore right is ItemFormat
-          updateCurrentAttributes(currentAttributes, right)
+          updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (right.content))
         }
         break
     }
@@ -97,7 +104,6 @@ const findNextPosition = (transaction, store, currentAttributes, left, right, co
 
 /**
  * @param {Transaction} transaction
- * @param {StructStore} store
  * @param {AbstractType<any>} parent
  * @param {number} index
  * @return {ItemTextListPosition}
@@ -105,11 +111,10 @@ const findNextPosition = (transaction, store, currentAttributes, left, right, co
  * @private
  * @function
  */
-const findPosition = (transaction, store, parent, index) => {
-  let currentAttributes = new Map()
-  let left = null
-  let right = parent._start
-  return findNextPosition(transaction, store, currentAttributes, left, right, index)
+const findPosition = (transaction, parent, index) => {
+  const currentAttributes = new Map()
+  const right = parent._start
+  return findNextPosition(transaction, currentAttributes, null, right, index)
 }
 
 /**
@@ -117,8 +122,8 @@ const findPosition = (transaction, store, parent, index) => {
  *
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} left
+ * @param {Item|null} right
  * @param {Map<string,any>} negatedAttributes
  * @return {ItemListPosition}
  *
@@ -130,21 +135,19 @@ const insertNegatedAttributes = (transaction, parent, left, right, negatedAttrib
   while (
     right !== null && (
       right.deleted === true || (
-        right.constructor === ItemFormat &&
-        // @ts-ignore right is ItemFormat
-        (negatedAttributes.get(right.key) === right.value)
+        right.content.constructor === ContentFormat &&
+        equalAttrs(negatedAttributes.get(/** @type {ContentFormat} */ (right.content).key), /** @type {ContentFormat} */ (right.content).value)
       )
     )
   ) {
     if (!right.deleted) {
-      // @ts-ignore right is ItemFormat
-      negatedAttributes.delete(right.key)
+      negatedAttributes.delete(/** @type {ContentFormat} */ (right.content).key)
     }
     left = right
     right = right.right
   }
-  for (let [key, val] of negatedAttributes) {
-    left = new ItemFormat(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, key, val)
+  for (const [key, val] of negatedAttributes) {
+    left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentFormat(key, val))
     left.integrate(transaction)
   }
   return { left, right }
@@ -152,14 +155,13 @@ const insertNegatedAttributes = (transaction, parent, left, right, negatedAttrib
 
 /**
  * @param {Map<string,any>} currentAttributes
- * @param {ItemFormat} item
+ * @param {ContentFormat} format
  *
  * @private
  * @function
  */
-const updateCurrentAttributes = (currentAttributes, item) => {
-  const value = item.value
-  const key = item.key
+const updateCurrentAttributes = (currentAttributes, format) => {
+  const { key, value } = format
   if (value === null) {
     currentAttributes.delete(key)
   } else {
@@ -168,8 +170,8 @@ const updateCurrentAttributes = (currentAttributes, item) => {
 }
 
 /**
- * @param {AbstractItem|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} left
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {Object<string,any>} attributes
  * @return {ItemListPosition}
@@ -184,11 +186,9 @@ const minimizeAttributeChanges = (left, right, currentAttributes, attributes) =>
       break
     } else if (right.deleted) {
       // continue
-    // @ts-ignore right is ItemFormat
-    } else if (right.constructor === ItemFormat && (attributes[right.key] || null) === right.value) {
+    } else if (right.content.constructor === ContentFormat && equalAttrs(attributes[(/** @type {ContentFormat} */ (right.content)).key] || null, /** @type {ContentFormat} */ (right.content).value)) {
       // found a format, update currentAttributes and continue
-      // @ts-ignore right is ItemFormat
-      updateCurrentAttributes(currentAttributes, right)
+      updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (right.content))
     } else {
       break
     }
@@ -201,8 +201,8 @@ const minimizeAttributeChanges = (left, right, currentAttributes, attributes) =>
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} left
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {Object<string,any>} attributes
  * @return {ItemInsertionResult}
@@ -213,13 +213,13 @@ const minimizeAttributeChanges = (left, right, currentAttributes, attributes) =>
 const insertAttributes = (transaction, parent, left, right, currentAttributes, attributes) => {
   const negatedAttributes = new Map()
   // insert format-start items
-  for (let key in attributes) {
+  for (const key in attributes) {
     const val = attributes[key]
     const currentVal = currentAttributes.get(key) || null
-    if (currentVal !== val) {
+    if (!equalAttrs(currentVal, val)) {
       // save negated attribute (set null if currentVal undefined)
       negatedAttributes.set(key, currentVal)
-      left = new ItemFormat(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, key, val)
+      left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentFormat(key, val))
       left.integrate(transaction)
     }
   }
@@ -229,10 +229,10 @@ const insertAttributes = (transaction, parent, left, right, currentAttributes, a
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} left
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
- * @param {string} text
+ * @param {string|object} text
  * @param {Object<string,any>} attributes
  * @return {ItemListPosition}
  *
@@ -240,7 +240,7 @@ const insertAttributes = (transaction, parent, left, right, currentAttributes, a
  * @function
  **/
 const insertText = (transaction, parent, left, right, currentAttributes, text, attributes) => {
-  for (let [key] of currentAttributes) {
+  for (const [key] of currentAttributes) {
     if (attributes[key] === undefined) {
       attributes[key] = null
     }
@@ -250,11 +250,8 @@ const insertText = (transaction, parent, left, right, currentAttributes, text, a
   left = insertPos.left
   right = insertPos.right
   // insert content
-  if (text.constructor === String) {
-    left = new ItemString(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, text)
-  } else {
-    left = new ItemEmbed(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, text)
-  }
+  const content = text.constructor === String ? new ContentString(/** @type {string} */ (text)) : new ContentEmbed(text)
+  left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, content)
   left.integrate(transaction)
   return insertNegatedAttributes(transaction, parent, left, insertPos.right, insertPos.negatedAttributes)
 }
@@ -262,8 +259,8 @@ const insertText = (transaction, parent, left, right, currentAttributes, text, a
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} left
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {number} length
  * @param {Object<string,any>} attributes
@@ -281,29 +278,26 @@ const formatText = (transaction, parent, left, right, currentAttributes, length,
   // iterate until first non-format or null is found
   // delete all formats with attributes[format.key] != null
   while (length > 0 && right !== null) {
-    if (right.deleted === false) {
-      switch (right.constructor) {
-        case ItemFormat:
-          // @ts-ignore right is ItemFormat
-          const attr = attributes[right.key]
+    if (!right.deleted) {
+      switch (right.content.constructor) {
+        case ContentFormat: {
+          const { key, value } = /** @type {ContentFormat} */ (right.content)
+          const attr = attributes[key]
           if (attr !== undefined) {
-            // @ts-ignore right is ItemFormat
-            if (attr === right.value) {
-              // @ts-ignore right is ItemFormat
-              negatedAttributes.delete(right.key)
+            if (equalAttrs(attr, value)) {
+              negatedAttributes.delete(key)
             } else {
-              // @ts-ignore right is ItemFormat
-              negatedAttributes.set(right.key, right.value)
+              negatedAttributes.set(key, value)
             }
             right.delete(transaction)
           }
-          // @ts-ignore right is ItemFormat
-          updateCurrentAttributes(currentAttributes, right)
+          updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (right.content))
           break
-        case ItemEmbed:
-        case ItemString:
+        }
+        case ContentEmbed:
+        case ContentString:
           if (length < right.length) {
-            getItemCleanStart(transaction, transaction.doc.store, createID(right.id.client, right.id.clock + length))
+            getItemCleanStart(transaction, createID(right.id.client, right.id.clock + length))
           }
           length -= right.length
           break
@@ -312,13 +306,24 @@ const formatText = (transaction, parent, left, right, currentAttributes, length,
     left = right
     right = right.right
   }
+  // Quill just assumes that the editor starts with a newline and that it always
+  // ends with a newline. We only insert that newline when a new newline is
+  // inserted - i.e when length is bigger than type.length
+  if (length > 0) {
+    let newlines = ''
+    for (; length > 0; length--) {
+      newlines += '\n'
+    }
+    left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentString(newlines))
+    left.integrate(transaction)
+  }
   return insertNegatedAttributes(transaction, parent, left, right, negatedAttributes)
 }
 
 /**
  * @param {Transaction} transaction
- * @param {AbstractItem|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} left
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {number} length
  * @return {ItemListPosition}
@@ -329,15 +334,14 @@ const formatText = (transaction, parent, left, right, currentAttributes, length,
 const deleteText = (transaction, left, right, currentAttributes, length) => {
   while (length > 0 && right !== null) {
     if (right.deleted === false) {
-      switch (right.constructor) {
-        case ItemFormat:
-          // @ts-ignore right is ItemFormat
-          updateCurrentAttributes(currentAttributes, right)
+      switch (right.content.constructor) {
+        case ContentFormat:
+          updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (right.content))
           break
-        case ItemEmbed:
-        case ItemString:
+        case ContentEmbed:
+        case ContentString:
           if (length < right.length) {
-            getItemCleanStart(transaction, transaction.doc.store, createID(right.id.client, right.id.clock + length))
+            getItemCleanStart(transaction, createID(right.id.client, right.id.clock + length))
           }
           length -= right.length
           right.delete(transaction)
@@ -396,11 +400,11 @@ export class YTextEvent extends YEvent {
   constructor (ytext, transaction) {
     super(ytext, transaction)
     /**
-     * @private
      * @type {Array<DeltaItem>|null}
      */
     this._delta = null
   }
+
   /**
    * Compute the changes in the delta format.
    * A {@link https://quilljs.com/docs/delta/|Quill Delta}) that represents the changes on the document.
@@ -411,13 +415,10 @@ export class YTextEvent extends YEvent {
    */
   get delta () {
     if (this._delta === null) {
-      const y = this.target.doc
-      // @ts-ignore
+      const y = /** @type {Doc} */ (this.target.doc)
+      this._delta = []
       transact(y, transaction => {
-        /**
-         * @type {Array<DeltaItem>}
-         */
-        const delta = []
+        const delta = /** @type {Array<DeltaItem>} */ (this._delta)
         const currentAttributes = new Map() // saves all current attributes for insert
         const oldAttributes = new Map()
         let item = this.target._start
@@ -428,11 +429,13 @@ export class YTextEvent extends YEvent {
         /**
          * @type {Object<string,any>}
          */
-        let attributes = {} // counts added or removed new attributes for retain
+        const attributes = {} // counts added or removed new attributes for retain
+        /**
+         * @type {string|object}
+         */
         let insert = ''
         let retain = 0
         let deleteLen = 0
-        this._delta = delta
         const addOp = () => {
           if (action !== null) {
             /**
@@ -448,7 +451,7 @@ export class YTextEvent extends YEvent {
                 op = { insert }
                 if (currentAttributes.size > 0) {
                   op.attributes = {}
-                  for (let [key, value] of currentAttributes) {
+                  for (const [key, value] of currentAttributes) {
                     if (value !== null) {
                       op.attributes[key] = value
                     }
@@ -460,7 +463,7 @@ export class YTextEvent extends YEvent {
                 op = { retain }
                 if (Object.keys(attributes).length > 0) {
                   op.attributes = {}
-                  for (let key in attributes) {
+                  for (const key in attributes) {
                     op.attributes[key] = attributes[key]
                   }
                 }
@@ -472,14 +475,13 @@ export class YTextEvent extends YEvent {
           }
         }
         while (item !== null) {
-          switch (item.constructor) {
-            case ItemEmbed:
+          switch (item.content.constructor) {
+            case ContentEmbed:
               if (this.adds(item)) {
                 if (!this.deletes(item)) {
                   addOp()
                   action = 'insert'
-                  // @ts-ignore item is ItemFormat
-                  insert = item.embed
+                  insert = /** @type {ContentEmbed} */ (item.content).embed
                   addOp()
                 }
               } else if (this.deletes(item)) {
@@ -496,15 +498,14 @@ export class YTextEvent extends YEvent {
                 retain += 1
               }
               break
-            case ItemString:
+            case ContentString:
               if (this.adds(item)) {
                 if (!this.deletes(item)) {
                   if (action !== 'insert') {
                     addOp()
                     action = 'insert'
                   }
-                  // @ts-ignore
-                  insert += item.string
+                  insert += /** @type {ContentString} */ (item.content).str
                 }
               } else if (this.deletes(item)) {
                 if (action !== 'delete') {
@@ -520,59 +521,45 @@ export class YTextEvent extends YEvent {
                 retain += item.length
               }
               break
-            case ItemFormat:
+            case ContentFormat: {
+              const { key, value } = /** @type {ContentFormat} */ (item.content)
               if (this.adds(item)) {
                 if (!this.deletes(item)) {
-                  // @ts-ignore item is ItemFormat
-                  const curVal = currentAttributes.get(item.key) || null
-                  // @ts-ignore item is ItemFormat
-                  if (curVal !== item.value) {
+                  const curVal = currentAttributes.get(key) || null
+                  if (!equalAttrs(curVal, value)) {
                     if (action === 'retain') {
                       addOp()
                     }
-                    // @ts-ignore item is ItemFormat
-                    if (item.value === (oldAttributes.get(item.key) || null)) {
-                      // @ts-ignore item is ItemFormat
-                      delete attributes[item.key]
+                    if (equalAttrs(value, (oldAttributes.get(key) || null))) {
+                      delete attributes[key]
                     } else {
-                      // @ts-ignore item is ItemFormat
-                      attributes[item.key] = item.value
+                      attributes[key] = value
                     }
                   } else {
                     item.delete(transaction)
                   }
                 }
               } else if (this.deletes(item)) {
-                // @ts-ignore item is ItemFormat
-                oldAttributes.set(item.key, item.value)
-                // @ts-ignore item is ItemFormat
-                const curVal = currentAttributes.get(item.key) || null
-                // @ts-ignore item is ItemFormat
-                if (curVal !== item.value) {
+                oldAttributes.set(key, value)
+                const curVal = currentAttributes.get(key) || null
+                if (!equalAttrs(curVal, value)) {
                   if (action === 'retain') {
                     addOp()
                   }
-                  // @ts-ignore item is ItemFormat
-                  attributes[item.key] = curVal
+                  attributes[key] = curVal
                 }
               } else if (!item.deleted) {
-                // @ts-ignore item is ItemFormat
-                oldAttributes.set(item.key, item.value)
-                // @ts-ignore item is ItemFormat
-                const attr = attributes[item.key]
+                oldAttributes.set(key, value)
+                const attr = attributes[key]
                 if (attr !== undefined) {
-                  // @ts-ignore item is ItemFormat
-                  if (attr !== item.value) {
+                  if (!equalAttrs(attr, value)) {
                     if (action === 'retain') {
                       addOp()
                     }
-                    // @ts-ignore item is ItemFormat
-                    if (item.value === null) {
-                      // @ts-ignore item is ItemFormat
-                      attributes[item.key] = item.value
+                    if (value === null) {
+                      attributes[key] = value
                     } else {
-                      // @ts-ignore item is ItemFormat
-                      delete attributes[item.key]
+                      delete attributes[key]
                     }
                   } else {
                     item.delete(transaction)
@@ -583,26 +570,25 @@ export class YTextEvent extends YEvent {
                 if (action === 'insert') {
                   addOp()
                 }
-                // @ts-ignore item is ItemFormat
-                updateCurrentAttributes(currentAttributes, item)
+                updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (item.content))
               }
               break
+            }
           }
           item = item.right
         }
         addOp()
-        while (this._delta.length > 0) {
-          let lastOp = this._delta[this._delta.length - 1]
+        while (delta.length > 0) {
+          const lastOp = delta[delta.length - 1]
           if (lastOp.retain !== undefined && lastOp.attributes === undefined) {
             // retain delta's if they don't assign attributes
-            this._delta.pop()
+            delta.pop()
           } else {
             break
           }
         }
       })
     }
-    // @ts-ignore _delta is defined above
     return this._delta
   }
 }
@@ -625,39 +611,42 @@ export class YText extends AbstractType {
     /**
      * Array of pending operations on this type
      * @type {Array<function():void>?}
-     * @private
      */
     this._pending = string !== undefined ? [() => this.insert(0, string)] : []
   }
 
+  /**
+   * Number of characters of this text type.
+   *
+   * @type {number}
+   */
   get length () {
     return this._length
   }
 
   /**
    * @param {Doc} y
-   * @param {ItemType} item
-   *
-   * @private
+   * @param {Item} item
    */
   _integrate (y, item) {
     super._integrate(y, item)
     try {
-      // @ts-ignore this._prelimContent is still defined
-      this._pending.forEach(f => f())
+      /** @type {Array<function>} */ (this._pending).forEach(f => f())
     } catch (e) {
       console.error(e)
     }
     this._pending = null
   }
 
+  _copy () {
+    return new YText()
+  }
+
   /**
    * Creates YTextEvent and calls observers.
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
-   *
-   * @private
    */
   _callObserver (transaction, parentSubs) {
     callTypeObservers(this, transaction, new YTextEvent(this, transaction))
@@ -671,19 +660,28 @@ export class YText extends AbstractType {
   toString () {
     let str = ''
     /**
-     * @type {AbstractItem|null}
+     * @type {Item|null}
      */
     let n = this._start
     while (n !== null) {
-      if (!n.deleted && n.countable && n.constructor === ItemString) {
-        // @ts-ignore
-        str += n.string
+      if (!n.deleted && n.countable && n.content.constructor === ContentString) {
+        str += /** @type {ContentString} */ (n.content).str
       }
       n = n.right
     }
     return str
   }
 
+  /**
+   * Returns the unformatted string representation of this YText type.
+   *
+   * @return {string}
+   * @public
+   */
+  toJSON () {
+    return this.toString()
+  }
+
   /**
    * Apply a {@link Delta} on this shared YText type.
    *
@@ -702,7 +700,15 @@ export class YText extends AbstractType {
         for (let i = 0; i < delta.length; i++) {
           const op = delta[i]
           if (op.insert !== undefined) {
-            pos = insertText(transaction, this, pos.left, pos.right, currentAttributes, op.insert, op.attributes || {})
+            // Quill assumes that the content starts with an empty paragraph.
+            // Yjs/Y.Text assumes that it starts empty. We always hide that
+            // there is a newline at the end of the content.
+            // If we omit this step, clients will see a different number of
+            // paragraphs, but nothing bad will happen.
+            const ins = (typeof op.insert === 'string' && i === delta.length - 1 && pos.right === null && op.insert.slice(-1) === '\n') ? op.insert.slice(0, -1) : op.insert
+            if (typeof ins !== 'string' || ins.length > 0) {
+              pos = insertText(transaction, this, pos.left, pos.right, currentAttributes, ins, op.attributes || {})
+            }
           } else if (op.retain !== undefined) {
             pos = formatText(transaction, this, pos.left, pos.right, currentAttributes, op.retain, op.attributes || {})
           } else if (op.delete !== undefined) {
@@ -711,8 +717,7 @@ export class YText extends AbstractType {
         }
       })
     } else {
-      // @ts-ignore
-      this._pending.push(() => this.applyDelta(delta))
+      /** @type {Array<function>} */ (this._pending).push(() => this.applyDelta(delta))
     }
   }
 
@@ -721,21 +726,19 @@ export class YText extends AbstractType {
    *
    * @param {Snapshot} [snapshot]
    * @param {Snapshot} [prevSnapshot]
+   * @param {function('removed' | 'added', ID):any} [computeYChange]
    * @return {any} The Delta representation of this type.
    *
    * @public
    */
-  toDelta (snapshot, prevSnapshot) {
+  toDelta (snapshot, prevSnapshot, computeYChange) {
     /**
      * @type{Array<any>}
      */
     const ops = []
     const currentAttributes = new Map()
+    const doc = /** @type {Doc} */ (this.doc)
     let str = ''
-    /**
-     * @type {AbstractItem|null}
-     */
-    // @ts-ignore
     let n = this._start
     function packStr () {
       if (str.length > 0) {
@@ -745,7 +748,7 @@ export class YText extends AbstractType {
          */
         const attributes = {}
         let addAttributes = false
-        for (let [key, value] of currentAttributes) {
+        for (const [key, value] of currentAttributes) {
           addAttributes = true
           attributes[key] = value
         }
@@ -760,38 +763,67 @@ export class YText extends AbstractType {
         str = ''
       }
     }
-    while (n !== null) {
-      if (isVisible(n, snapshot) || (prevSnapshot !== undefined && isVisible(n, prevSnapshot))) {
-        switch (n.constructor) {
-          case ItemString:
-            const cur = currentAttributes.get('ychange')
-            if (snapshot !== undefined && !isVisible(n, snapshot)) {
-              if (cur === undefined || cur.user !== n.id.client || cur.state !== 'removed') {
-                packStr()
-                currentAttributes.set('ychange', { user: n.id.client, state: 'removed' })
-              }
-            } else if (prevSnapshot !== undefined && !isVisible(n, prevSnapshot)) {
-              if (cur === undefined || cur.user !== n.id.client || cur.state !== 'added') {
-                packStr()
-                currentAttributes.set('ychange', { user: n.id.client, state: 'added' })
-              }
-            } else if (cur !== undefined) {
-              packStr()
-              currentAttributes.delete('ychange')
-            }
-            // @ts-ignore
-            str += n.string
-            break
-          case ItemFormat:
-            packStr()
-            // @ts-ignore
-            updateCurrentAttributes(currentAttributes, n)
-            break
-        }
+    // snapshots are merged again after the transaction, so we need to keep the
+    // transalive until we are done
+    transact(doc, transaction => {
+      if (snapshot) {
+        splitSnapshotAffectedStructs(transaction, snapshot)
       }
-      n = n.right
-    }
-    packStr()
+      if (prevSnapshot) {
+        splitSnapshotAffectedStructs(transaction, prevSnapshot)
+      }
+      while (n !== null) {
+        if (isVisible(n, snapshot) || (prevSnapshot !== undefined && isVisible(n, prevSnapshot))) {
+          switch (n.content.constructor) {
+            case ContentString: {
+              const cur = currentAttributes.get('ychange')
+              if (snapshot !== undefined && !isVisible(n, snapshot)) {
+                if (cur === undefined || cur.user !== n.id.client || cur.state !== 'removed') {
+                  packStr()
+                  currentAttributes.set('ychange', computeYChange ? computeYChange('removed', n.id) : { type: 'removed' })
+                }
+              } else if (prevSnapshot !== undefined && !isVisible(n, prevSnapshot)) {
+                if (cur === undefined || cur.user !== n.id.client || cur.state !== 'added') {
+                  packStr()
+                  currentAttributes.set('ychange', computeYChange ? computeYChange('added', n.id) : { type: 'added' })
+                }
+              } else if (cur !== undefined) {
+                packStr()
+                currentAttributes.delete('ychange')
+              }
+              str += /** @type {ContentString} */ (n.content).str
+              break
+            }
+            case ContentEmbed: {
+              packStr()
+              /**
+               * @type {Object<string,any>}
+               */
+              const op = {
+                insert: /** @type {ContentEmbed} */ (n.content).embed
+              }
+              if (currentAttributes.size > 0) {
+                const attrs = /** @type {Object<string,any>} */ ({})
+                op.attributes = attrs
+                for (const [key, value] of currentAttributes) {
+                  attrs[key] = value
+                }
+              }
+              ops.push(op)
+              break
+            }
+            case ContentFormat:
+              if (isVisible(n, snapshot)) {
+                packStr()
+                updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (n.content))
+              }
+              break
+          }
+        }
+        n = n.right
+      }
+      packStr()
+    }, splitSnapshotAffectedStructs)
     return ops
   }
 
@@ -800,24 +832,28 @@ export class YText extends AbstractType {
    *
    * @param {number} index The index at which to start inserting.
    * @param {String} text The text to insert at the specified position.
-   * @param {TextAttributes} attributes Optionally define some formatting
+   * @param {TextAttributes} [attributes] Optionally define some formatting
    *                                    information to apply on the inserted
    *                                    Text.
    * @public
    */
-  insert (index, text, attributes = {}) {
+  insert (index, text, attributes) {
     if (text.length <= 0) {
       return
     }
     const y = this.doc
     if (y !== null) {
       transact(y, transaction => {
-        const { left, right, currentAttributes } = findPosition(transaction, y.store, this, index)
+        const { left, right, currentAttributes } = findPosition(transaction, this, index)
+        if (!attributes) {
+          attributes = {}
+          // @ts-ignore
+          currentAttributes.forEach((v, k) => { attributes[k] = v })
+        }
         insertText(transaction, this, left, right, currentAttributes, text, attributes)
       })
     } else {
-      // @ts-ignore
-      this._pending.push(() => this.insert(index, text, attributes))
+      /** @type {Array<function>} */ (this._pending).push(() => this.insert(index, text, attributes))
     }
   }
 
@@ -838,12 +874,11 @@ export class YText extends AbstractType {
     const y = this.doc
     if (y !== null) {
       transact(y, transaction => {
-        const { left, right, currentAttributes } = findPosition(transaction, y.store, this, index)
+        const { left, right, currentAttributes } = findPosition(transaction, this, index)
         insertText(transaction, this, left, right, currentAttributes, embed, attributes)
       })
     } else {
-      // @ts-ignore
-      this._pending.push(() => this.insertEmbed(index, embed, attributes))
+      /** @type {Array<function>} */ (this._pending).push(() => this.insertEmbed(index, embed, attributes))
     }
   }
 
@@ -862,12 +897,11 @@ export class YText extends AbstractType {
     const y = this.doc
     if (y !== null) {
       transact(y, transaction => {
-        const { left, right, currentAttributes } = findPosition(transaction, y.store, this, index)
+        const { left, right, currentAttributes } = findPosition(transaction, this, index)
         deleteText(transaction, left, right, currentAttributes, length)
       })
     } else {
-      // @ts-ignore
-      this._pending.push(() => this.delete(index, length))
+      /** @type {Array<function>} */ (this._pending).push(() => this.delete(index, length))
     }
   }
 
@@ -885,22 +919,19 @@ export class YText extends AbstractType {
     const y = this.doc
     if (y !== null) {
       transact(y, transaction => {
-        let { left, right, currentAttributes } = findPosition(transaction, y.store, this, index)
+        const { left, right, currentAttributes } = findPosition(transaction, this, index)
         if (right === null) {
           return
         }
         formatText(transaction, this, left, right, currentAttributes, length, attributes)
       })
     } else {
-      // @ts-ignore
-      this._pending.push(() => this.format(index, length, attributes))
+      /** @type {Array<function>} */ (this._pending).push(() => this.format(index, length, attributes))
     }
   }
 
   /**
    * @param {encoding.Encoder} encoder
-   *
-   * @private
    */
   _write (encoder) {
     encoding.writeVarUint(encoder, YTextRefID)

src/types/YXmlElement.js

@@ -8,7 +8,7 @@ import {
   typeMapGetAll,
   typeListForEach,
   YXmlElementRefID,
-  Snapshot, Doc, ItemType // eslint-disable-line
+  Snapshot, Doc, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -24,10 +24,9 @@ import * as decoding from 'lib0/decoding.js'
 export class YXmlElement extends YXmlFragment {
   constructor (nodeName = 'UNDEFINED') {
     super()
-    this.nodeName = nodeName.toUpperCase()
+    this.nodeName = nodeName
     /**
      * @type {Map<string, any>|null}
-     * @private
      */
     this._prelimAttrs = new Map()
   }
@@ -40,26 +39,20 @@ export class YXmlElement extends YXmlFragment {
    * * Observer functions are fired
    *
    * @param {Doc} y The Yjs instance
-   * @param {ItemType} item
-   * @private
+   * @param {Item} item
    */
   _integrate (y, item) {
     super._integrate(y, item)
-    // @ts-ignore
-    this.insert(0, this._prelimContent)
-    this._prelimContent = null
-    // @ts-ignore
-    this._prelimAttrs.forEach((value, key) => {
+    ;(/** @type {Map<string, any>} */ (this._prelimAttrs)).forEach((value, key) => {
       this.setAttribute(key, value)
     })
-    this._prelimContent = null
+    this._prelimAttrs = null
   }
 
   /**
    * Creates an Item with the same effect as this Item (without position effect)
    *
    * @return {YXmlElement}
-   * @private
    */
   _copy () {
     return new YXmlElement(this.nodeName)
@@ -78,7 +71,7 @@ export class YXmlElement extends YXmlFragment {
     const attrs = this.getAttributes()
     const stringBuilder = []
     const keys = []
-    for (let key in attrs) {
+    for (const key in attrs) {
       keys.push(key)
     }
     keys.sort()
@@ -105,8 +98,7 @@ export class YXmlElement extends YXmlFragment {
         typeMapDelete(transaction, this, attributeName)
       })
     } else {
-      // @ts-ignore
-      this._prelimAttrs.delete(attributeName)
+      /** @type {Map<string,any>} */ (this._prelimAttrs).delete(attributeName)
     }
   }
 
@@ -124,8 +116,7 @@ export class YXmlElement extends YXmlFragment {
         typeMapSet(transaction, this, attributeName, attributeValue)
       })
     } else {
-      // @ts-ignore
-      this._prelimAttrs.set(attributeName, attributeValue)
+      /** @type {Map<string, any>} */ (this._prelimAttrs).set(attributeName, attributeValue)
     }
   }
 
@@ -139,15 +130,14 @@ export class YXmlElement extends YXmlFragment {
    * @public
    */
   getAttribute (attributeName) {
-    // @ts-ignore
-    return typeMapGet(this, attributeName)
+    return /** @type {any} */ (typeMapGet(this, attributeName))
   }
 
   /**
    * Returns all attribute name/value pairs in a JSON Object.
    *
    * @param {Snapshot} [snapshot]
-   * @return {Object} A JSON Object that describes the attributes.
+   * @return {Object<string, any>} A JSON Object that describes the attributes.
    *
    * @public
    */
@@ -172,8 +162,8 @@ export class YXmlElement extends YXmlFragment {
    */
   toDOM (_document = document, hooks = {}, binding) {
     const dom = _document.createElement(this.nodeName)
-    let attrs = this.getAttributes()
-    for (let key in attrs) {
+    const attrs = this.getAttributes()
+    for (const key in attrs) {
       dom.setAttribute(key, attrs[key])
     }
     typeListForEach(this, yxml => {
@@ -191,7 +181,6 @@ export class YXmlElement extends YXmlFragment {
    *
    * This is called when this Item is sent to a remote peer.
    *
-   * @private
    * @param {encoding.Encoder} encoder The encoder to write data to.
    */
   _write (encoder) {
@@ -204,7 +193,6 @@ export class YXmlElement extends YXmlFragment {
  * @param {decoding.Decoder} decoder
  * @return {YXmlElement}
  *
- * @private
  * @function
  */
 export const readYXmlElement = decoder => new YXmlElement(decoding.readVarString(decoder))

src/types/YXmlFragment.js

@@ -14,7 +14,7 @@ import {
   YXmlFragmentRefID,
   callTypeObservers,
   transact,
-  Transaction, ItemType, YXmlText, YXmlHook, Snapshot // eslint-disable-line
+  Doc, ContentType, Transaction, Item, YXmlText, YXmlHook, Snapshot // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -59,16 +59,16 @@ export class YXmlTreeWalker {
     this._filter = f
     this._root = root
     /**
-     * @type {ItemType | null}
+     * @type {Item}
      */
-    // @ts-ignore
-    this._currentNode = root._start
+    this._currentNode = /** @type {Item} */ (root._start)
     this._firstCall = true
   }
 
   [Symbol.iterator] () {
     return this
   }
+
   /**
    * Get the next node.
    *
@@ -77,18 +77,21 @@ export class YXmlTreeWalker {
    * @public
    */
   next () {
+    /**
+     * @type {Item|null}
+     */
     let n = this._currentNode
-    if (n !== null && (!this._firstCall || n.deleted || !this._filter(n.type))) { // if first call, we check if we can use the first item
+    let type = /** @type {ContentType} */ (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 {
-        if (!n.deleted && (n.type.constructor === YXmlElement || n.type.constructor === YXmlFragment) && n.type._start !== null) {
+        type = /** @type {ContentType} */ (n.content).type
+        if (!n.deleted && (type.constructor === YXmlElement || type.constructor === YXmlFragment) && type._start !== null) {
           // walk down in the tree
-          // @ts-ignore
-          n = n.type._start
+          n = type._start
         } else {
           // walk right or up in the tree
           while (n !== null) {
             if (n.right !== null) {
-              // @ts-ignore
               n = n.right
               break
             } else if (n.parent === this._root) {
@@ -98,16 +101,15 @@ export class YXmlTreeWalker {
             }
           }
         }
-      } while (n !== null && (n.deleted || !this._filter(n.type)))
+      } while (n !== null && (n.deleted || !this._filter(/** @type {ContentType} */ (n.content).type)))
     }
     this._firstCall = false
-    this._currentNode = n
     if (n === null) {
-      // @ts-ignore return undefined if done=true (the expected result)
+      // @ts-ignore
       return { value: undefined, done: true }
     }
-    // @ts-ignore
-    return { value: n.type, done: false }
+    this._currentNode = n
+    return { value: /** @type {any} */ (n.content).type, done: false }
   }
 }
 
@@ -125,10 +127,34 @@ export class YXmlFragment extends AbstractType {
     super()
     /**
      * @type {Array<any>|null}
-     * @private
      */
     this._prelimContent = []
   }
+
+  /**
+   * Integrate this type into the Yjs instance.
+   *
+   * * Save this struct in the os
+   * * This type is sent to other client
+   * * Observer functions are fired
+   *
+   * @param {Doc} y The Yjs instance
+   * @param {Item} item
+   */
+  _integrate (y, item) {
+    super._integrate(y, item)
+    this.insert(0, /** @type {Array<any>} */ (this._prelimContent))
+    this._prelimContent = null
+  }
+
+  _copy () {
+    return new YXmlFragment()
+  }
+
+  get length () {
+    return this._prelimContent === null ? this._length : this._prelimContent.length
+  }
+
   /**
    * Create a subtree of childNodes.
    *
@@ -168,7 +194,7 @@ export class YXmlFragment extends AbstractType {
   querySelector (query) {
     query = query.toUpperCase()
     // @ts-ignore
-    const iterator = new YXmlTreeWalker(this, element => element.nodeName === query)
+    const iterator = new YXmlTreeWalker(this, element => element.nodeName && element.nodeName.toUpperCase() === query)
     const next = iterator.next()
     if (next.done) {
       return null
@@ -191,12 +217,11 @@ export class YXmlFragment extends AbstractType {
   querySelectorAll (query) {
     query = query.toUpperCase()
     // @ts-ignore
-    return Array.from(new YXmlTreeWalker(this, element => element.nodeName === query))
+    return Array.from(new YXmlTreeWalker(this, element => element.nodeName && element.nodeName.toUpperCase() === query))
   }
 
   /**
    * Creates YXmlEvent and calls observers.
-   * @private
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
@@ -214,6 +239,9 @@ export class YXmlFragment extends AbstractType {
     return typeListMap(this, xml => xml.toString()).join('')
   }
 
+  /**
+   * @return {string}
+   */
   toJSON () {
     return this.toString()
   }
@@ -281,6 +309,7 @@ export class YXmlFragment extends AbstractType {
       this._prelimContent.splice(index, length)
     }
   }
+
   /**
    * Transforms this YArray to a JavaScript Array.
    *
@@ -289,13 +318,13 @@ export class YXmlFragment extends AbstractType {
   toArray () {
     return typeListToArray(this)
   }
+
   /**
    * 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.
    *
-   * @private
    * @param {encoding.Encoder} encoder The encoder to write data to.
    */
   _write (encoder) {

src/types/YXmlHook.js

@@ -25,8 +25,6 @@ export class YXmlHook extends YMap {
 
   /**
    * Creates an Item with the same effect as this Item (without position effect)
-   *
-   * @private
    */
   _copy () {
     return new YXmlHook(this.hookName)
@@ -69,8 +67,6 @@ 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.
-   *
-   * @private
    */
   _write (encoder) {
     super._write(encoder)

src/types/YXmlText.js

@@ -9,6 +9,10 @@ import * as decoding from 'lib0/decoding.js' // eslint-disable-line
  * simple formatting information like bold and italic.
  */
 export class YXmlText extends YText {
+  _copy () {
+    return new YXmlText()
+  }
+
   /**
    * Creates a Dom Element that mirrors this YXmlText.
    *
@@ -36,9 +40,9 @@ export class YXmlText extends YText {
     // @ts-ignore
     return this.toDelta().map(delta => {
       const nestedNodes = []
-      for (let nodeName in delta.attributes) {
+      for (const nodeName in delta.attributes) {
         const attrs = []
-        for (let key in delta.attributes[nodeName]) {
+        for (const key in delta.attributes[nodeName]) {
           attrs.push({ key, value: delta.attributes[nodeName][key] })
         }
         // sort attributes to get a unique order
@@ -53,7 +57,7 @@ export class YXmlText extends YText {
         const node = nestedNodes[i]
         str += `<${node.nodeName}`
         for (let j = 0; j < node.attrs.length; j++) {
-          const attr = node.attrs[i]
+          const attr = node.attrs[j]
           str += ` ${attr.key}="${attr.value}"`
         }
         str += '>'
@@ -66,14 +70,15 @@ export class YXmlText extends YText {
     }).join('')
   }
 
+  /**
+   * @return {string}
+   */
   toJSON () {
     return this.toString()
   }
 
   /**
    * @param {encoding.Encoder} encoder
-   *
-   * @private
    */
   _write (encoder) {
     encoding.writeVarUint(encoder, YXmlTextRefID)

src/utils/DeleteSet.js

@@ -3,15 +3,18 @@ import {
   findIndexSS,
   createID,
   getState,
-  AbstractStruct, AbstractItem, StructStore, Transaction, ID // eslint-disable-line
+  splitItem,
+  iterateStructs,
+  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'
 
-class DeleteItem {
+export class DeleteItem {
   /**
    * @param {number} clock
    * @param {number} len
@@ -39,36 +42,26 @@ export class DeleteSet {
   constructor () {
     /**
      * @type {Map<number,Array<DeleteItem>>}
-     * @private
      */
     this.clients = new Map()
   }
 }
 
 /**
- * Iterate over all structs that were deleted.
- *
- * This function expects that the deletes structs are not merged. Hence, you can
- * probably only use it in type observes and `afterTransaction` events. But not
- * in `afterTransactionCleanup`.
+ * Iterate over all structs that the DeleteSet gc's.
  *
+ * @param {Transaction} transaction
  * @param {DeleteSet} ds
- * @param {StructStore} store
- * @param {function(AbstractStruct):void} f
+ * @param {function(GC|Item):void} f
  *
  * @function
  */
-export const iterateDeletedStructs = (ds, store, f) =>
+export const iterateDeletedStructs = (transaction, ds, f) =>
   ds.clients.forEach((deletes, clientid) => {
-    const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(clientid))
+    const structs = /** @type {Array<GC|Item>} */ (transaction.doc.store.clients.get(clientid))
     for (let i = 0; i < deletes.length; i++) {
       const del = deletes[i]
-      let index = findIndexSS(structs, del.clock)
-      let struct
-      do {
-        struct = structs[index++]
-        f(struct)
-      } while (index < structs.length && structs[index].id.clock < del.clock + del.len)
+      iterateStructs(transaction, structs, del.clock, del.len, f)
     }
   })
 
@@ -142,6 +135,32 @@ export const sortAndMergeDeleteSet = ds => {
   })
 }
 
+/**
+ * @param {Array<DeleteSet>} dss
+ * @return {DeleteSet} A fresh DeleteSet
+ */
+export const mergeDeleteSets = dss => {
+  const merged = new DeleteSet()
+  for (let dssI = 0; dssI < dss.length; dssI++) {
+    dss[dssI].clients.forEach((delsLeft, client) => {
+      if (!merged.clients.has(client)) {
+        // Write all missing keys from current ds and all following.
+        // If merged already contains `client` current ds has already been added.
+        /**
+         * @type {Array<DeleteItem>}
+         */
+        const dels = delsLeft.slice()
+        for (let i = dssI + 1; i < dss.length; i++) {
+          array.appendTo(dels, dss[i].clients.get(client) || [])
+        }
+        merged.clients.set(client, dels)
+      }
+    })
+  }
+  sortAndMergeDeleteSet(merged)
+  return merged
+}
+
 /**
  * @param {DeleteSet} ds
  * @param {ID} id
@@ -154,6 +173,8 @@ export const addToDeleteSet = (ds, id, length) => {
   map.setIfUndefined(ds.clients, id.client, () => []).push(new DeleteItem(id.clock, length))
 }
 
+export const createDeleteSet = () => new DeleteSet()
+
 /**
  * @param {StructStore} ss
  * @return {DeleteSet} Merged and sorted DeleteSet
@@ -162,7 +183,7 @@ export const addToDeleteSet = (ds, id, length) => {
  * @function
  */
 export const createDeleteSetFromStructStore = ss => {
-  const ds = new DeleteSet()
+  const ds = createDeleteSet()
   ss.clients.forEach((structs, client) => {
     /**
      * @type {Array<DeleteItem>}
@@ -209,6 +230,26 @@ export const writeDeleteSet = (encoder, ds) => {
   })
 }
 
+/**
+ * @param {decoding.Decoder} decoder
+ * @return {DeleteSet}
+ *
+ * @private
+ * @function
+ */
+export const readDeleteSet = decoder => {
+  const ds = new DeleteSet()
+  const numClients = decoding.readVarUint(decoder)
+  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))
+    }
+  }
+  return ds
+}
+
 /**
  * @param {decoding.Decoder} decoder
  * @param {Transaction} transaction
@@ -217,7 +258,7 @@ export const writeDeleteSet = (encoder, ds) => {
  * @private
  * @function
  */
-export const readDeleteSet = (decoder, transaction, store) => {
+export const readAndApplyDeleteSet = (decoder, transaction, store) => {
   const unappliedDS = new DeleteSet()
   const numClients = decoding.readVarUint(decoder)
   for (let i = 0; i < numClients; i++) {
@@ -235,13 +276,13 @@ export const readDeleteSet = (decoder, transaction, store) => {
         let index = findIndexSS(structs, clock)
         /**
          * We can ignore the case of GC and Delete structs, because we are going to skip them
-         * @type {AbstractItem}
+         * @type {Item}
          */
         // @ts-ignore
         let struct = structs[index]
         // split the first item if necessary
         if (!struct.deleted && struct.id.clock < clock) {
-          structs.splice(index + 1, 0, struct.splitAt(transaction, clock - struct.id.clock))
+          structs.splice(index + 1, 0, splitItem(transaction, struct, clock - struct.id.clock))
           index++ // increase we now want to use the next struct
         }
         while (index < structs.length) {
@@ -250,7 +291,7 @@ export const readDeleteSet = (decoder, transaction, store) => {
           if (struct.id.clock < clock + len) {
             if (!struct.deleted) {
               if (clock + len < struct.id.clock + struct.length) {
-                structs.splice(index, 0, struct.splitAt(transaction, clock + len - struct.id.clock))
+                structs.splice(index, 0, splitItem(transaction, struct, clock + len - struct.id.clock))
               }
               struct.delete(transaction)
             }
@@ -264,6 +305,7 @@ export const readDeleteSet = (decoder, transaction, store) => {
     }
   }
   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)))

src/utils/Doc.js

@@ -10,24 +10,30 @@ import {
   YMap,
   YXmlFragment,
   transact,
-  AbstractItem, Transaction, YEvent // eslint-disable-line
+  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'
 
+export const generateNewClientId = random.uint32
+
 /**
  * A Yjs instance handles the state of shared data.
  * @extends Observable<string>
  */
 export class Doc extends Observable {
   /**
-   * @param {Object|undefined} conf configuration
+   * @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.
    */
-  constructor (conf = {}) {
+  constructor ({ gc = true, gcFilter = () => true } = {}) {
     super()
-    this.clientID = random.uint32()
+    this.gc = gc
+    this.gcFilter = gcFilter
+    this.clientID = generateNewClientId()
     /**
      * @type {Map<string, AbstractType<YEvent>>}
      */
@@ -35,15 +41,14 @@ export class Doc extends Observable {
     this.store = new StructStore()
     /**
      * @type {Transaction | null}
-     * @private
      */
     this._transaction = null
     /**
      * @type {Array<Transaction>}
-     * @private
      */
     this._transactionCleanups = []
   }
+
   /**
    * Changes that happen inside of a transaction are bundled. This means that
    * the observer fires _after_ the transaction is finished and that all changes
@@ -58,6 +63,7 @@ export class Doc extends Observable {
   transact (f, origin = null) {
     transact(this, f, origin)
   }
+
   /**
    * Define a shared data type.
    *
@@ -97,8 +103,9 @@ export class Doc extends Observable {
         // @ts-ignore
         const t = new TypeConstructor()
         t._map = type._map
-        type._map.forEach(/** @param {AbstractItem?} n */ n => {
+        type._map.forEach(/** @param {Item?} n */ n => {
           for (; n !== null; n = n.left) {
+            // @ts-ignore
             n.parent = t
           }
         })
@@ -116,6 +123,7 @@ export class Doc extends Observable {
     }
     return type
   }
+
   /**
    * @template T
    * @param {string} name
@@ -127,6 +135,7 @@ export class Doc extends Observable {
     // @ts-ignore
     return this.get(name, YArray)
   }
+
   /**
    * @param {string} name
    * @return {YText}
@@ -137,6 +146,7 @@ export class Doc extends Observable {
     // @ts-ignore
     return this.get(name, YText)
   }
+
   /**
    * @param {string} name
    * @return {YMap<any>}
@@ -147,6 +157,7 @@ export class Doc extends Observable {
     // @ts-ignore
     return this.get(name, YMap)
   }
+
   /**
    * @param {string} name
    * @return {YXmlFragment}
@@ -157,15 +168,15 @@ export class Doc extends Observable {
     // @ts-ignore
     return this.get(name, YXmlFragment)
   }
+
   /**
    * Emit `destroy` event and unregister all event handlers.
-   *
-   * @protected
    */
   destroy () {
     this.emit('destroyed', [true])
     super.destroy()
   }
+
   /**
    * @param {string} eventName
    * @param {function} f
@@ -173,6 +184,7 @@ export class Doc extends Observable {
   on (eventName, f) {
     super.on(eventName, f)
   }
+
   /**
    * @param {string} eventName
    * @param {function} f

src/utils/ID.js

@@ -1,5 +1,5 @@
 
-import { AbstractType } from '../internals' // eslint-disable-line
+import { AbstractType } from '../internals.js' // eslint-disable-line
 
 import * as decoding from 'lib0/decoding.js'
 import * as encoding from 'lib0/encoding.js'
@@ -81,7 +81,7 @@ export const readID = decoder =>
  */
 export const findRootTypeKey = type => {
   // @ts-ignore _y must be defined, otherwise unexpected case
-  for (let [key, value] of type.doc.share) {
+  for (const [key, value] of type.doc.share) {
     if (value === type) {
       return key
     }

src/utils/PermanentUserData.js

@@ -0,0 +1,142 @@
+
+import {
+  YArray,
+  YMap,
+  readDeleteSet,
+  writeDeleteSet,
+  createDeleteSet,
+  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 { mergeDeleteSets, isDeleted } from './DeleteSet.js'
+
+export class PermanentUserData {
+  /**
+   * @param {Doc} doc
+   * @param {YMap<any>} [storeType]
+   */
+  constructor (doc, storeType = doc.getMap('users')) {
+    /**
+     * @type {Map<string,DeleteSet>}
+     */
+    const dss = new Map()
+    this.yusers = storeType
+    this.doc = doc
+    /**
+     * Maps from clientid to userDescription
+     *
+     * @type {Map<number,string>}
+     */
+    this.clients = new Map()
+    this.dss = dss
+    /**
+     * @param {YMap<any>} user
+     * @param {string} userDescription
+     */
+    const initUser = (user, userDescription) => {
+      /**
+       * @type {YArray<Uint8Array>}
+       */
+      const ds = user.get('ds')
+      const ids = user.get('ids')
+      const addClientId = /** @param {number} clientid */ clientid => this.clients.set(clientid, userDescription)
+      ds.observe(/** @param {YArrayEvent<any>} event */ event => {
+        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(ds.map(encodedDs => readDeleteSet(decoding.createDecoder(encodedDs)))))
+      ids.observe(/** @param {YArrayEvent<any>} event */ event =>
+        event.changes.added.forEach(item => item.content.getContent().forEach(addClientId))
+      )
+      ids.forEach(addClientId)
+    }
+    // observe users
+    storeType.observe(event => {
+      event.keysChanged.forEach(userDescription =>
+        initUser(storeType.get(userDescription), userDescription)
+      )
+    })
+    // add intial data
+    storeType.forEach(initUser)
+  }
+
+  /**
+   * @param {Doc} doc
+   * @param {number} clientid
+   * @param {string} userDescription
+   * @param {Object} [conf]
+   * @param {function(Transaction, DeleteSet):boolean} [conf.filter]
+   */
+  setUserMapping (doc, clientid, userDescription, { filter = () => true } = {}) {
+    const users = this.yusers
+    let user = users.get(userDescription)
+    if (!user) {
+      user = new YMap()
+      user.set('ids', new YArray())
+      user.set('ds', new YArray())
+      users.set(userDescription, user)
+    }
+    user.get('ids').push([clientid])
+    users.observe(event => {
+      setTimeout(() => {
+        const userOverwrite = users.get(userDescription)
+        if (userOverwrite !== user) {
+          // user was overwritten, port all data over to the next user object
+          // @todo Experiment with Y.Sets here
+          user = userOverwrite
+          // @todo iterate over old type
+          this.clients.forEach((_userDescription, clientid) => {
+            if (userDescription === _userDescription) {
+              user.get('ids').push([clientid])
+            }
+          })
+          const encoder = encoding.createEncoder()
+          const ds = this.dss.get(userDescription)
+          if (ds) {
+            writeDeleteSet(encoder, ds)
+            user.get('ds').push([encoding.toUint8Array(encoder)])
+          }
+        }
+      }, 0)
+    })
+    doc.on('afterTransaction', /** @param {Transaction} transaction */ transaction => {
+      setTimeout(() => {
+        const yds = user.get('ds')
+        const ds = transaction.deleteSet
+        if (transaction.local && ds.clients.size > 0 && filter(transaction, ds)) {
+          const encoder = encoding.createEncoder()
+          writeDeleteSet(encoder, ds)
+          yds.push([encoding.toUint8Array(encoder)])
+        }
+      })
+    })
+  }
+
+  /**
+   * @param {number} clientid
+   * @return {any}
+   */
+  getUserByClientId (clientid) {
+    return this.clients.get(clientid) || null
+  }
+
+  /**
+   * @param {ID} id
+   * @return {string | null}
+   */
+  getUserByDeletedId (id) {
+    for (const [userDescription, ds] of this.dss) {
+      if (isDeleted(ds, id)) {
+        return userDescription
+      }
+    }
+    return null
+  }
+}

src/utils/RelativePosition.js

@@ -1,16 +1,15 @@
 
 import {
-  getItem,
-  getItemType,
   createID,
   writeID,
   readID,
   compareIDs,
   getState,
   findRootTypeKey,
-  AbstractItem,
-  ItemType,
-  ID, StructStore, Doc, AbstractType // eslint-disable-line
+  Item,
+  ContentType,
+  followRedone,
+  ID, Doc, AbstractType // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -64,7 +63,7 @@ export class RelativePosition {
 }
 
 /**
- * @param {Object} json
+ * @param {any} json
  * @return {RelativePosition}
  *
  * @function
@@ -223,19 +222,22 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
     if (getState(store, rightID.client) <= rightID.clock) {
       return null
     }
-    const right = getItem(store, rightID)
-    if (!(right instanceof AbstractItem)) {
+    const res = followRedone(store, rightID)
+    const right = res.item
+    if (!(right instanceof Item)) {
       return null
     }
-    index = right.deleted || !right.countable ? 0 : rightID.clock - right.id.clock
-    let n = right.left
-    while (n !== null) {
-      if (!n.deleted && n.countable) {
-        index += n.length
-      }
-      n = n.left
-    }
     type = right.parent
+    if (type._item === null || !type._item.deleted) {
+      index = right.deleted || !right.countable ? 0 : res.diff
+      let n = right.left
+      while (n !== null) {
+        if (!n.deleted && n.countable) {
+          index += n.length
+        }
+        n = n.left
+      }
+    }
   } else {
     if (tname !== null) {
       type = doc.get(tname)
@@ -244,9 +246,9 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
         // type does not exist yet
         return null
       }
-      const struct = getItemType(store, typeID)
-      if (struct instanceof ItemType) {
-        type = struct.type
+      const { item } = followRedone(store, typeID)
+      if (item instanceof Item && item.content instanceof ContentType) {
+        type = item.content.type
       } else {
         // struct is garbage collected
         return null
@@ -256,9 +258,6 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
     }
     index = type._length
   }
-  if (type._item !== null && type._item.deleted) {
-    return null
-  }
   return createAbsolutePosition(type, index)
 }
 

src/utils/Snapshot.js

@@ -1,42 +1,138 @@
 
 import {
   isDeleted,
-  DeleteSet, AbstractItem // eslint-disable-line
+  createDeleteSetFromStructStore,
+  getStateVector,
+  getItemCleanStart,
+  createID,
+  iterateDeletedStructs,
+  writeDeleteSet,
+  writeStateVector,
+  readDeleteSet,
+  readStateVector,
+  createDeleteSet,
+  getState,
+  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'
+
 export class Snapshot {
   /**
    * @param {DeleteSet} ds
-   * @param {Map<number,number>} sm state map
+   * @param {Map<number,number>} sv state map
    */
-  constructor (ds, sm) {
+  constructor (ds, sv) {
     /**
      * @type {DeleteSet}
-     * @private
      */
     this.ds = ds
     /**
      * State Map
      * @type {Map<number,number>}
-     * @private
      */
-    this.sm = sm
+    this.sv = sv
   }
 }
 
+/**
+ * @param {Snapshot} snap1
+ * @param {Snapshot} snap2
+ * @return {boolean}
+ */
+export const equalSnapshots = (snap1, snap2) => {
+  const ds1 = snap1.ds.clients
+  const ds2 = snap2.ds.clients
+  const sv1 = snap1.sv
+  const sv2 = snap2.sv
+  if (sv1.size !== sv2.size || ds1.size !== ds2.size) {
+    return false
+  }
+  for (const [key, value] of sv1) {
+    if (sv2.get(key) !== value) {
+      return false
+    }
+  }
+  for (const [client, dsitems1] of ds1) {
+    const dsitems2 = ds2.get(client) || []
+    if (dsitems1.length !== dsitems2.length) {
+      return false
+    }
+    for (let i = 0; i < dsitems1.length; i++) {
+      const dsitem1 = dsitems1[i]
+      const dsitem2 = dsitems2[i]
+      if (dsitem1.clock !== dsitem2.clock || dsitem1.len !== dsitem2.len) {
+        return false
+      }
+    }
+  }
+  return true
+}
+
+/**
+ * @param {Snapshot} snapshot
+ * @return {Uint8Array}
+ */
+export const encodeSnapshot = snapshot => {
+  const encoder = encoding.createEncoder()
+  writeDeleteSet(encoder, snapshot.ds)
+  writeStateVector(encoder, snapshot.sv)
+  return encoding.toUint8Array(encoder)
+}
+
+/**
+ * @param {Uint8Array} buf
+ * @return {Snapshot}
+ */
+export const decodeSnapshot = buf => {
+  const decoder = decoding.createDecoder(buf)
+  return new Snapshot(readDeleteSet(decoder), readStateVector(decoder))
+}
+
 /**
  * @param {DeleteSet} ds
  * @param {Map<number,number>} sm
+ * @return {Snapshot}
  */
 export const createSnapshot = (ds, sm) => new Snapshot(ds, sm)
 
+export const emptySnapshot = createSnapshot(createDeleteSet(), new Map())
+
 /**
- * @param {AbstractItem} item
+ * @param {Doc} doc
+ * @return {Snapshot}
+ */
+export const snapshot = doc => createSnapshot(createDeleteSetFromStructStore(doc.store), getStateVector(doc.store))
+
+/**
+ * @param {Item} item
  * @param {Snapshot|undefined} snapshot
  *
  * @protected
  * @function
  */
 export const isVisible = (item, snapshot) => snapshot === undefined ? !item.deleted : (
-  snapshot.sm.has(item.id.client) && (snapshot.sm.get(item.id.client) || 0) > item.id.clock && !isDeleted(snapshot.ds, item.id)
+  snapshot.sv.has(item.id.client) && (snapshot.sv.get(item.id.client) || 0) > item.id.clock && !isDeleted(snapshot.ds, item.id)
 )
+
+/**
+ * @param {Transaction} transaction
+ * @param {Snapshot} snapshot
+ */
+export const splitSnapshotAffectedStructs = (transaction, snapshot) => {
+  const meta = map.setIfUndefined(transaction.meta, splitSnapshotAffectedStructs, set.create)
+  const store = transaction.doc.store
+  // check if we already split for this snapshot
+  if (!meta.has(snapshot)) {
+    snapshot.sv.forEach((clock, client) => {
+      if (clock < getState(store, client)) {
+        getItemCleanStart(transaction, createID(client, clock))
+      }
+    })
+    iterateDeletedStructs(transaction, snapshot.ds, item => {})
+    meta.add(snapshot)
+  }
+}

src/utils/StructStore.js

@@ -1,7 +1,8 @@
 
 import {
   GC,
-  Transaction, AbstractStructRef, ID, ItemType, AbstractItem, AbstractStruct // eslint-disable-line
+  splitItem,
+  GCRef, ItemRef, Transaction, ID, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as math from 'lib0/math.js'
@@ -11,8 +12,7 @@ import * as decoding from 'lib0/decoding.js' // eslint-disable-line
 export class StructStore {
   constructor () {
     /**
-     * @type {Map<number,Array<AbstractStruct>>}
-     * @private
+     * @type {Map<number,Array<GC|Item>>}
      */
     this.clients = new Map()
     /**
@@ -21,20 +21,17 @@ export class StructStore {
      * 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<AbstractStructRef>}>}
-     * @private
+     * @type {Map<number,{i:number,refs:Array<GCRef|ItemRef>}>}
      */
     this.pendingClientsStructRefs = new Map()
     /**
      * Stack of pending structs waiting for struct dependencies
      * Maximum length of stack is structReaders.size
-     * @type {Array<AbstractStructRef>}
-     * @private
+     * @type {Array<GCRef|ItemRef>}
      */
     this.pendingStack = []
     /**
      * @type {Array<decoding.Decoder>}
-     * @private
      */
     this.pendingDeleteReaders = []
   }
@@ -96,7 +93,7 @@ export const integretyCheck = store => {
 
 /**
  * @param {StructStore} store
- * @param {AbstractStruct} struct
+ * @param {GC|Item} struct
  *
  * @private
  * @function
@@ -150,14 +147,14 @@ export const findIndexSS = (structs, clock) => {
  *
  * @param {StructStore} store
  * @param {ID} id
- * @return {AbstractStruct}
+ * @return {GC|Item}
  *
  * @private
  * @function
  */
 export const find = (store, id) => {
   /**
-   * @type {Array<AbstractStruct>}
+   * @type {Array<GC|Item>}
    */
   // @ts-ignore
   const structs = store.clients.get(id.client)
@@ -169,7 +166,7 @@ export const find = (store, id) => {
  *
  * @param {StructStore} store
  * @param {ID} id
- * @return {AbstractItem}
+ * @return {Item}
  *
  * @private
  * @function
@@ -178,45 +175,33 @@ export const find = (store, id) => {
 export const getItem = (store, id) => 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 {ItemType}
- *
- * @private
- * @function
+ * @param {Transaction} transaction
+ * @param {Array<Item|GC>} structs
+ * @param {number} clock
  */
-// @ts-ignore
-export const getItemType = (store, id) => find(store, id)
+export const findIndexCleanStart = (transaction, structs, clock) => {
+  const index = findIndexSS(structs, clock)
+  const struct = structs[index]
+  if (struct.id.clock < clock && struct instanceof Item) {
+    structs.splice(index + 1, 0, splitItem(transaction, struct, clock - struct.id.clock))
+    return index + 1
+  }
+  return index
+}
 
 /**
  * Expects that id is actually in store. This function throws or is an infinite loop otherwise.
  *
  * @param {Transaction} transaction
- * @param {StructStore} store
  * @param {ID} id
- * @return {AbstractItem}
+ * @return {Item}
  *
  * @private
  * @function
  */
-export const getItemCleanStart = (transaction, store, id) => {
-  /**
-   * @type {Array<AbstractItem>}
-   */
-  // @ts-ignore
-  const structs = store.clients.get(id.client)
-  const index = findIndexSS(structs, id.clock)
-  /**
-   * @type {AbstractItem}
-   */
-  let struct = structs[index]
-  if (struct.id.clock < id.clock && struct.constructor !== GC) {
-    struct = struct.splitAt(transaction, id.clock - struct.id.clock)
-    structs.splice(index + 1, 0, struct)
-  }
-  return struct
+export const getItemCleanStart = (transaction, id) => {
+  const structs = /** @type {Array<Item>} */ (transaction.doc.store.clients.get(id.client))
+  return structs[findIndexCleanStart(transaction, structs, id.clock)]
 }
 
 /**
@@ -225,21 +210,21 @@ export const getItemCleanStart = (transaction, store, id) => {
  * @param {Transaction} transaction
  * @param {StructStore} store
  * @param {ID} id
- * @return {AbstractItem}
+ * @return {Item}
  *
  * @private
  * @function
  */
 export const getItemCleanEnd = (transaction, store, id) => {
   /**
-   * @type {Array<AbstractItem>}
+   * @type {Array<Item>}
    */
   // @ts-ignore
   const structs = store.clients.get(id.client)
   const index = findIndexSS(structs, id.clock)
   const struct = structs[index]
   if (id.clock !== struct.id.clock + struct.length - 1 && struct.constructor !== GC) {
-    structs.splice(index + 1, 0, struct.splitAt(transaction, id.clock - struct.id.clock + 1))
+    structs.splice(index + 1, 0, splitItem(transaction, struct, id.clock - struct.id.clock + 1))
   }
   return struct
 }
@@ -247,17 +232,40 @@ export const getItemCleanEnd = (transaction, store, id) => {
 /**
  * Replace `item` with `newitem` in store
  * @param {StructStore} store
- * @param {AbstractStruct} struct
- * @param {AbstractStruct} newStruct
+ * @param {GC|Item} struct
+ * @param {GC|Item} newStruct
  *
  * @private
  * @function
  */
 export const replaceStruct = (store, struct, newStruct) => {
-  /**
-   * @type {Array<AbstractStruct>}
-   */
-  // @ts-ignore
-  const structs = store.clients.get(struct.id.client)
+  const structs = /** @type {Array<GC|Item>} */ (store.clients.get(struct.id.client))
   structs[findIndexSS(structs, struct.id.clock)] = newStruct
 }
+
+/**
+ * Iterate over a range of structs
+ *
+ * @param {Transaction} transaction
+ * @param {Array<Item|GC>} structs
+ * @param {number} clockStart Inclusive start
+ * @param {number} len
+ * @param {function(GC|Item):void} f
+ *
+ * @function
+ */
+export const iterateStructs = (transaction, structs, clockStart, len, f) => {
+  if (len === 0) {
+    return
+  }
+  const clockEnd = clockStart + len
+  let index = findIndexCleanStart(transaction, structs, clockStart)
+  let struct
+  do {
+    struct = structs[index++]
+    if (clockEnd < struct.id.clock + struct.length) {
+      findIndexCleanStart(transaction, structs, clockEnd)
+    }
+    f(struct)
+  } while (index < structs.length && structs[index].id.clock < clockEnd)
+}

src/utils/Transaction.js

@@ -9,13 +9,17 @@ import {
   getStateVector,
   findIndexSS,
   callEventHandlerListeners,
-  AbstractItem,
-  ID, AbstractType, AbstractStruct, YEvent, Doc // eslint-disable-line
+  Item,
+  generateNewClientId,
+  StructStore, ID, 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'
 
 /**
  * A transaction is created for every change on the Yjs model. It is possible
@@ -45,8 +49,9 @@ export class Transaction {
   /**
    * @param {Doc} doc
    * @param {any} origin
+   * @param {boolean} local
    */
-  constructor (doc, origin) {
+  constructor (doc, origin, local) {
     /**
      * The Yjs instance.
      * @type {Doc}
@@ -70,7 +75,7 @@ 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)
+     * Maps from type to parentSubs (`item.parentSub = null` for YArray)
      * @type {Map<AbstractType<YEvent>,Set<String|null>>}
      */
     this.changed = new Map()
@@ -82,13 +87,22 @@ export class Transaction {
     this.changedParentTypes = new Map()
     /**
      * @type {Set<ID>}
-     * @private
      */
     this._mergeStructs = new Set()
     /**
      * @type {any}
      */
     this.origin = origin
+    /**
+     * Stores meta information on the transaction
+     * @type {Map<any,any>}
+     */
+    this.meta = new Map()
+    /**
+     * Whether this change originates from this doc.
+     * @type {boolean}
+     */
+    this.local = local
   }
 }
 
@@ -117,22 +131,226 @@ export const nextID = transaction => {
   return createID(y.clientID, getState(y.store, y.clientID))
 }
 
+/**
+ * If `type.parent` was added in current transaction, `type` technically
+ * did not change, it was just added and we should not fire events for `type`.
+ *
+ * @param {Transaction} transaction
+ * @param {AbstractType<YEvent>} type
+ * @param {string|null} parentSub
+ */
+export const addChangedTypeToTransaction = (transaction, type, parentSub) => {
+  const item = type._item
+  if (item === null || (item.id.clock < (transaction.beforeState.get(item.id.client) || 0) && !item.deleted)) {
+    map.setIfUndefined(transaction.changed, type, set.create).add(parentSub)
+  }
+}
+
+/**
+ * @param {Array<AbstractStruct>} structs
+ * @param {number} pos
+ */
+const tryToMergeWithLeft = (structs, pos) => {
+  const left = structs[pos - 1]
+  const right = 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))
+      }
+    }
+  }
+}
+
+/**
+ * @param {DeleteSet} ds
+ * @param {StructStore} store
+ * @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 (let di = deleteItems.length - 1; di >= 0; di--) {
+      const deleteItem = deleteItems[di]
+      const endDeleteItemClock = deleteItem.clock + deleteItem.len
+      for (
+        let si = findIndexSS(structs, deleteItem.clock), struct = structs[si];
+        si < structs.length && struct.id.clock < endDeleteItemClock;
+        struct = structs[++si]
+      ) {
+        const struct = structs[si]
+        if (deleteItem.clock + deleteItem.len <= struct.id.clock) {
+          break
+        }
+        if (struct instanceof Item && struct.deleted && !struct.keep && gcFilter(struct)) {
+          struct.gc(store, false)
+        }
+      }
+    }
+  }
+}
+
+/**
+ * @param {DeleteSet} ds
+ * @param {StructStore} store
+ */
+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))
+    for (let di = deleteItems.length - 1; di >= 0; di--) {
+      const deleteItem = deleteItems[di]
+      // start with merging the item next to the last deleted item
+      const mostRightIndexToCheck = math.min(structs.length - 1, 1 + findIndexSS(structs, deleteItem.clock + deleteItem.len - 1))
+      for (
+        let si = mostRightIndexToCheck, struct = structs[si];
+        si > 0 && struct.id.clock >= deleteItem.clock;
+        struct = structs[--si]
+      ) {
+        tryToMergeWithLeft(structs, si)
+      }
+    }
+  }
+}
+
+/**
+ * @param {DeleteSet} ds
+ * @param {StructStore} store
+ * @param {function(Item):boolean} gcFilter
+ */
+export const tryGc = (ds, store, gcFilter) => {
+  tryGcDeleteSet(ds, store, gcFilter)
+  tryMergeDeleteSet(ds, store)
+}
+
+/**
+ * @param {Array<Transaction>} transactionCleanups
+ * @param {number} i
+ */
+const cleanupTransactions = (transactionCleanups, i) => {
+  if (i < transactionCleanups.length) {
+    const transaction = transactionCleanups[i]
+    const doc = transaction.doc
+    const store = doc.store
+    const ds = transaction.deleteSet
+    try {
+      sortAndMergeDeleteSet(ds)
+      transaction.afterState = getStateVector(transaction.doc.store)
+      doc._transaction = null
+      doc.emit('beforeObserverCalls', [transaction, doc])
+      /**
+       * An array of event callbacks.
+       *
+       * Each callback is called even if the other ones throw errors.
+       *
+       * @type {Array<function():void>}
+       */
+      const fs = []
+      // observe events on changed types
+      transaction.changed.forEach((subs, itemtype) =>
+        fs.push(() => {
+          if (itemtype._item === null || !itemtype._item.deleted) {
+            itemtype._callObserver(transaction, subs)
+          }
+        })
+      )
+      fs.push(() => {
+        // deep observe events
+        transaction.changedParentTypes.forEach((events, type) =>
+          fs.push(() => {
+            // We need to think about the possibility that the user transforms the
+            // Y.Doc in the event.
+            if (type._item === null || !type._item.deleted) {
+              events = events
+                .filter(event =>
+                  event.target._item === null || !event.target._item.deleted
+                )
+              events
+                .forEach(event => {
+                  event.currentTarget = type
+                })
+              // We don't need to check for events.length
+              // because we know it has at least one element
+              callEventHandlerListeners(type._dEH, events, transaction)
+            }
+          })
+        )
+        fs.push(() => doc.emit('afterTransaction', [transaction, doc]))
+      })
+      callAll(fs, [])
+    } finally {
+      // Replace deleted items with ItemDeleted / GC.
+      // This is where content is actually remove from the Yjs Doc.
+      if (doc.gc) {
+        tryGcDeleteSet(ds, store, doc.gcFilter)
+      }
+      tryMergeDeleteSet(ds, store)
+
+      // on all affected store.clients props, try to merge
+      for (const [client, clock] of transaction.afterState) {
+        const beforeClock = transaction.beforeState.get(client) || 0
+        if (beforeClock !== clock) {
+          const structs = /** @type {Array<AbstractStruct>} */ (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))
+        const replacedStructPos = findIndexSS(structs, clock)
+        if (replacedStructPos + 1 < structs.length) {
+          tryToMergeWithLeft(structs, replacedStructPos + 1)
+        }
+        if (replacedStructPos > 0) {
+          tryToMergeWithLeft(structs, replacedStructPos)
+        }
+      }
+      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.')
+      }
+      // @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])
+        }
+      }
+      if (transactionCleanups.length <= i + 1) {
+        doc._transactionCleanups = []
+      } else {
+        cleanupTransactions(transactionCleanups, i + 1)
+      }
+    }
+  }
+}
+
 /**
  * Implements the functionality of `y.transact(()=>{..})`
  *
  * @param {Doc} doc
  * @param {function(Transaction):void} f
- * @param {any} [origin]
+ * @param {any} [origin=true]
  *
- * @private
  * @function
  */
-export const transact = (doc, f, origin = null) => {
+export const transact = (doc, f, origin = null, local = true) => {
   const transactionCleanups = doc._transactionCleanups
   let initialCall = false
   if (doc._transaction === null) {
     initialCall = true
-    doc._transaction = new Transaction(doc, origin)
+    doc._transaction = new Transaction(doc, origin, local)
     transactionCleanups.push(doc._transaction)
     doc.emit('beforeTransaction', [doc._transaction, doc])
   }
@@ -142,142 +360,13 @@ export const transact = (doc, f, origin = null) => {
     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
-      for (let i = 0; i < transactionCleanups.length; i++) {
-        const transaction = transactionCleanups[i]
-        const store = transaction.doc.store
-        const ds = transaction.deleteSet
-        sortAndMergeDeleteSet(ds)
-        transaction.afterState = getStateVector(transaction.doc.store)
-        doc._transaction = null
-        doc.emit('beforeObserverCalls', [transaction, doc])
-        // emit change events on changed types
-        transaction.changed.forEach((subs, itemtype) => {
-          itemtype._callObserver(transaction, subs)
-        })
-        transaction.changedParentTypes.forEach((events, type) => {
-          events = events
-            .filter(event =>
-              event.target._item === null || !event.target._item.deleted
-            )
-          events
-            .forEach(event => {
-              event.currentTarget = type
-            })
-          // we don't need to check for events.length
-          // because we know it has at least one element
-          callEventHandlerListeners(type._dEH, events, transaction)
-        })
-        doc.emit('afterTransaction', [transaction, doc])
-        /**
-         * @param {Array<AbstractStruct>} structs
-         * @param {number} pos
-         */
-        const tryToMergeWithLeft = (structs, pos) => {
-          const left = structs[pos - 1]
-          const right = structs[pos]
-          if (left.deleted === right.deleted && left.constructor === right.constructor) {
-            if (left.mergeWith(right)) {
-              structs.splice(pos, 1)
-              if (right instanceof AbstractItem && right.parentSub !== null && right.parent._map.get(right.parentSub) === right) {
-                // @ts-ignore we already did a constructor check above
-                right.parent._map.set(right.parentSub, left)
-              }
-            }
-          }
-        }
-        // replace deleted items with ItemDeleted / GC
-        for (const [client, deleteItems] of ds.clients) {
-          /**
-           * @type {Array<AbstractStruct>}
-           */
-          // @ts-ignore
-          const structs = store.clients.get(client)
-          for (let di = deleteItems.length - 1; di >= 0; di--) {
-            const deleteItem = deleteItems[di]
-            const endDeleteItemClock = deleteItem.clock + deleteItem.len
-            for (
-              let si = findIndexSS(structs, deleteItem.clock), struct = structs[si];
-              si < structs.length && struct.id.clock < endDeleteItemClock;
-              struct = structs[++si]
-            ) {
-              const struct = structs[si]
-              if (deleteItem.clock + deleteItem.len <= struct.id.clock) {
-                break
-              }
-              if (struct.deleted && struct instanceof AbstractItem) {
-                struct.gc(store, false)
-              }
-            }
-          }
-        }
-        // 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) {
-          /**
-           * @type {Array<AbstractStruct>}
-           */
-          // @ts-ignore
-          const structs = 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
-            const mostRightIndexToCheck = math.min(structs.length - 1, 1 + findIndexSS(structs, deleteItem.clock + deleteItem.len - 1))
-            for (
-              let si = mostRightIndexToCheck, struct = structs[si];
-              si > 0 && struct.id.clock >= deleteItem.clock;
-              struct = structs[--si]
-            ) {
-              tryToMergeWithLeft(structs, si)
-            }
-          }
-        }
-
-        // on all affected store.clients props, try to merge
-        for (const [client, clock] of transaction.afterState) {
-          const beforeClock = transaction.beforeState.get(client) || 0
-          if (beforeClock !== clock) {
-            /**
-             * @type {Array<AbstractStruct>}
-             */
-            // @ts-ignore
-            const structs = 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
-          /**
-           * @type {Array<AbstractStruct>}
-           */
-          // @ts-ignore
-          const structs = store.clients.get(client)
-          const replacedStructPos = findIndexSS(structs, clock)
-          if (replacedStructPos + 1 < structs.length) {
-            tryToMergeWithLeft(structs, replacedStructPos + 1)
-          }
-          if (replacedStructPos > 0) {
-            tryToMergeWithLeft(structs, replacedStructPos)
-          }
-        }
-        // @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])
-          }
-        }
-      }
-      doc._transactionCleanups = []
+      // 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

@@ -1,203 +1,283 @@
-// @ts-nocheck
-
 import {
+  mergeDeleteSets,
+  iterateDeletedStructs,
+  keepItem,
+  transact,
+  redoItem,
+  iterateStructs,
   isParentOf,
   createID,
-  transact
+  followRedone,
+  getItemCleanStart,
+  getState,
+  Transaction, Doc, Item, GC, DeleteSet, AbstractType // eslint-disable-line
 } from '../internals.js'
 
-/**
- * @private
- */
-class ReverseOperation {
-  constructor (y, transaction, bindingInfos) {
-    this.created = new Date()
-    const beforeState = transaction.beforeState
-    if (beforeState.has(y.userID)) {
-      this.toState = createID(y.userID, y.ss.getState(y.userID) - 1)
-      this.fromState = createID(y.userID, beforeState.get(y.userID))
-    } else {
-      this.toState = null
-      this.fromState = null
-    }
-    this.deletedStructs = new Set()
-    transaction.deletedStructs.forEach(struct => {
-      this.deletedStructs.add({
-        from: struct._id,
-        len: struct._length
-      })
-    })
-    /**
-     * Maps from binding to binding information (e.g. cursor information)
-     */
-    this.bindingInfos = bindingInfos
-  }
-}
+import * as time from 'lib0/time.js'
+import { Observable } from 'lib0/observable.js'
 
-/**
- * @private
- * @function
- */
-function applyReverseOperation (y, scope, reverseBuffer) {
-  let performedUndo = false
-  let undoOp = null
-  transact(y, () => {
-    while (!performedUndo && reverseBuffer.length > 0) {
-      undoOp = reverseBuffer.pop()
-      // make sure that it is possible to iterate {from}-{to}
-      if (undoOp.fromState !== null) {
-        y.os.getItemCleanStart(undoOp.fromState)
-        y.os.getItemCleanEnd(undoOp.toState)
-        y.os.iterate(undoOp.fromState, undoOp.toState, op => {
-          while (op._deleted && op._redone !== null) {
-            op = op._redone
-          }
-          if (op._deleted === false && isParentOf(scope, op)) {
-            performedUndo = true
-            op._delete(y)
-          }
-        })
-      }
-      const redoitems = new Set()
-      for (let del of undoOp.deletedStructs) {
-        const fromState = del.from
-        const toState = createID(fromState.user, fromState.clock + del.len - 1)
-        y.os.getItemCleanStart(fromState)
-        y.os.getItemCleanEnd(toState)
-        y.os.iterate(fromState, toState, op => {
-          if (
-            isParentOf(scope, op) &&
-            op._parent !== y &&
-            (
-              op._id.user !== y.userID ||
-              undoOp.fromState === null ||
-              op._id.clock < undoOp.fromState.clock ||
-              op._id.clock > undoOp.toState.clock
-            )
-          ) {
-            redoitems.add(op)
-          }
-        })
-      }
-      redoitems.forEach(op => {
-        const opUndone = op._redo(y, redoitems)
-        performedUndo = performedUndo || opUndone
-      })
-    }
-  })
-  if (performedUndo && undoOp !== null) {
-    // should be performed after the undo transaction
-    undoOp.bindingInfos.forEach((info, binding) => {
-      binding._restoreUndoStackInfo(info)
-    })
-  }
-  return performedUndo
-}
-
-/**
- * Saves a history of locally applied operations. The UndoManager handles the
- * undoing and redoing of locally created changes.
- *
- * @private
- * @function
- */
-export class UndoManager {
+class StackItem {
   /**
-   * @param {YType} scope The scope on which to listen for changes.
-   * @param {Object} options Optionally provided configuration.
+   * @param {DeleteSet} ds
+   * @param {number} start clock start of the local client
+   * @param {number} len
    */
-  constructor (scope, options = {}) {
-    this.options = options
-    this._bindings = new Set(options.bindings)
-    options.captureTimeout = options.captureTimeout == null ? 500 : options.captureTimeout
-    this._undoBuffer = []
-    this._redoBuffer = []
-    this._scope = scope
-    this._undoing = false
-    this._redoing = false
-    this._lastTransactionWasUndo = false
-    const doc = scope.doc
-    this.y = doc
-    let bindingInfos
-    doc.on('beforeTransaction', (y, transaction, remote) => {
-      if (!remote) {
-        // Store binding information before transaction is executed
-        // By restoring the binding information, we can make sure that the state
-        // before the transaction can be recovered
-        bindingInfos = new Map()
-        this._bindings.forEach(binding => {
-          bindingInfos.set(binding, binding._getUndoStackInfo())
-        })
-      }
-    })
-    doc.on('afterTransaction', (y, transaction, remote) => {
-      if (!remote && transaction.changedParentTypes.has(scope)) {
-        let reverseOperation = new ReverseOperation(y, transaction, bindingInfos)
-        if (!this._undoing) {
-          let lastUndoOp = this._undoBuffer.length > 0 ? this._undoBuffer[this._undoBuffer.length - 1] : null
-          if (
-            this._redoing === false &&
-            this._lastTransactionWasUndo === false &&
-            lastUndoOp !== null &&
-            ((options.captureTimeout < 0) || (reverseOperation.created.getTime() - lastUndoOp.created.getTime()) <= options.captureTimeout)
-          ) {
-            lastUndoOp.created = reverseOperation.created
-            if (reverseOperation.toState !== null) {
-              lastUndoOp.toState = reverseOperation.toState
-              if (lastUndoOp.fromState === null) {
-                lastUndoOp.fromState = reverseOperation.fromState
-              }
-            }
-            reverseOperation.deletedStructs.forEach(lastUndoOp.deletedStructs.add, lastUndoOp.deletedStructs)
-          } else {
-            this._lastTransactionWasUndo = false
-            this._undoBuffer.push(reverseOperation)
-          }
-          if (!this._redoing) {
-            this._redoBuffer = []
-          }
-        } else {
-          this._lastTransactionWasUndo = true
-          this._redoBuffer.push(reverseOperation)
+  constructor (ds, start, len) {
+    this.ds = ds
+    this.start = start
+    this.len = len
+    /**
+     * Use this to save and restore metadata like selection range
+     */
+    this.meta = new Map()
+  }
+}
+
+/**
+ * @param {UndoManager} undoManager
+ * @param {Array<StackItem>} stack
+ * @param {string} eventType
+ * @return {StackItem?}
+ */
+const popStackItem = (undoManager, stack, eventType) => {
+  /**
+   * Whether a change happened
+   * @type {StackItem?}
+   */
+  let result = 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
+      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 => {
+        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)))) {
+            itemsToDelete.push(struct)
+          }
+        }
+      })
+      // 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--) {
+        const item = itemsToDelete[i]
+        if (undoManager.deleteFilter(item)) {
+          item.delete(transaction)
+          performedChange = true
+        }
+      }
+      result = stackItem
+      if (result != null) {
+        undoManager.emit('stack-item-popped', [{ stackItem: result, type: eventType }, undoManager])
+      }
+    }
+  }, undoManager)
+  return result
+}
+
+/**
+ * @typedef {Object} UndoManagerOptions
+ * @property {number} [UndoManagerOptions.captureTimeout=500]
+ * @property {function(Item):boolean} [UndoManagerOptions.deleteFilter=()=>true] Sometimes
+ * it is necessary to filter whan 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])]
+ */
+
+/**
+ * Fires 'stack-item-added' event when a stack item was added to either the undo- or
+ * the redo-stack. You may store additional stack information via the
+ * metadata property on `event.stackItem.meta` (it is a `Map` of metadata properties).
+ * 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'>}
+ */
+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
+    }
+    super()
+    this.scope = typeScope instanceof Array ? typeScope : [typeScope]
+    this.deleteFilter = deleteFilter
+    trackedOrigins.add(this)
+    this.trackedOrigins = trackedOrigins
+    /**
+     * @type {Array<StackItem>}
+     */
+    this.undoStack = []
+    /**
+     * @type {Array<StackItem>}
+     */
+    this.redoStack = []
+    /**
+     * Whether the client is currently undoing (calling UndoManager.undo)
+     *
+     * @type {boolean}
+     */
+    this.undoing = false
+    this.redoing = false
+    this.doc = /** @type {Doc} */ (this.scope[0].doc)
+    this.lastChange = 0
+    this.doc.on('afterTransaction', /** @param {Transaction} transaction */ 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)))) {
+        return
+      }
+      const undoing = this.undoing
+      const redoing = this.redoing
+      const stack = undoing ? this.redoStack : this.undoStack
+      if (undoing) {
+        this.stopCapturing() // next undo should not be appended to last stack item
+      } else if (!redoing) {
+        // neither undoing nor redoing: delete redoStack
+        this.redoStack = []
+      }
+      const beforeState = transaction.beforeState.get(this.doc.clientID) || 0
+      const afterState = transaction.afterState.get(this.doc.clientID) || 0
+      const now = time.getUnixTime()
+      if (now - this.lastChange < 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
+      } else {
+        // create a new stack op
+        stack.push(new StackItem(transaction.deleteSet, beforeState, afterState - beforeState))
+      }
+      if (!undoing && !redoing) {
+        this.lastChange = now
+      }
+      // make sure that deleted structs are not gc'd
+      iterateDeletedStructs(transaction, transaction.deleteSet, /** @param {Item|GC} item */ item => {
+        if (item instanceof Item && this.scope.some(type => isParentOf(type, item))) {
+          keepItem(item, true)
+        }
+      })
+      this.emit('stack-item-added', [{ stackItem: stack[stack.length - 1], origin: transaction.origin, type: undoing ? 'redo' : 'undo' }, this])
     })
   }
 
-  /**
-   * Enforce that the next change is created as a separate item in the undo stack
-   *
-   * @private
-   * @function
-   */
-  flushChanges () {
-    this._lastTransactionWasUndo = true
+  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)
+          }
+        })
+      }
+      this.undoStack.forEach(clearItem)
+      this.redoStack.forEach(clearItem)
+    })
+    this.undoStack = []
+    this.redoStack = []
   }
 
   /**
-   * Undo the last locally created change.
+   * UndoManager merges Undo-StackItem if they are created within time-gap
+   * smaller than `options.captureTimeout`. Call `um.stopCapturing()` so that the next
+   * StackItem won't be merged.
    *
-   * @private
-   * @function
+   *
+   * @example
+   *     // without stopCapturing
+   *     ytext.insert(0, 'a')
+   *     ytext.insert(1, 'b')
+   *     um.undo()
+   *     ytext.toString() // => '' (note that 'ab' was removed)
+   *     // with stopCapturing
+   *     ytext.insert(0, 'a')
+   *     um.stopCapturing()
+   *     ytext.insert(0, 'b')
+   *     um.undo()
+   *     ytext.toString() // => 'a' (note that only 'b' was removed)
+   *
+   */
+  stopCapturing () {
+    this.lastChange = 0
+  }
+
+  /**
+   * Undo last changes on type.
+   *
+   * @return {StackItem?} Returns StackItem if a change was applied
    */
   undo () {
-    this._undoing = true
-    const performedUndo = applyReverseOperation(this.y, this._scope, this._undoBuffer)
-    this._undoing = false
-    return performedUndo
+    this.undoing = true
+    let res
+    try {
+      res = popStackItem(this, this.undoStack, 'undo')
+    } finally {
+      this.undoing = false
+    }
+    return res
   }
 
   /**
-   * Redo the last locally created change.
+   * Redo last undo operation.
    *
-   * @private
-   * @function
+   * @return {StackItem?} Returns StackItem if a change was applied
    */
   redo () {
-    this._redoing = true
-    const performedRedo = applyReverseOperation(this.y, this._scope, this._redoBuffer)
-    this._redoing = false
-    return performedRedo
+    this.redoing = true
+    let res
+    try {
+      res = popStackItem(this, this.redoStack, 'redo')
+    } finally {
+      this.redoing = false
+    }
+    return res
   }
 }
-}

src/utils/YEvent.js

@@ -1,9 +1,12 @@
 
 import {
   isDeleted,
-  AbstractType, Transaction, AbstractStruct // eslint-disable-line
+  Item, AbstractType, Transaction, AbstractStruct // eslint-disable-line
 } from '../internals.js'
 
+import * as set from 'lib0/set.js'
+import * as array from 'lib0/array.js'
+
 /**
  * YEvent describes the changes on a YType.
  */
@@ -28,6 +31,10 @@ export class YEvent {
      * @type {Transaction}
      */
     this.transaction = transaction
+    /**
+     * @type {Object|null}
+     */
+    this._changes = null
   }
 
   /**
@@ -49,6 +56,8 @@ export class YEvent {
   /**
    * Check if a struct is deleted by this event.
    *
+   * In contrast to change.deleted, this method also returns true if the struct was added and then deleted.
+   *
    * @param {AbstractStruct} struct
    * @return {boolean}
    */
@@ -59,12 +68,121 @@ export class YEvent {
   /**
    * Check if a struct is added by this event.
    *
+   * In contrast to change.deleted, this method also returns true if the struct was added and then deleted.
+   *
    * @param {AbstractStruct} struct
    * @return {boolean}
    */
   adds (struct) {
     return struct.id.clock >= (this.transaction.beforeState.get(struct.id.client) || 0)
   }
+
+  /**
+   * @return {{added:Set<Item>,deleted:Set<Item>,delta:Array<{insert:Array<any>}|{delete:number}|{retain:number}>}}
+   */
+  get changes () {
+    let changes = this._changes
+    if (changes === null) {
+      const target = this.target
+      const added = set.create()
+      const deleted = set.create()
+      /**
+       * @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
+      }
+      const changed = /** @type Set<string|null> */ (this.transaction.changed.get(target))
+      if (changed.has(null)) {
+        /**
+         * @type {any}
+         */
+        let lastOp = null
+        const packOp = () => {
+          if (lastOp) {
+            delta.push(lastOp)
+          }
+        }
+        for (let item = target._start; item !== null; item = item.right) {
+          if (item.deleted) {
+            if (this.deletes(item) && !this.adds(item)) {
+              if (lastOp === null || lastOp.delete === undefined) {
+                packOp()
+                lastOp = { delete: 0 }
+              }
+              lastOp.delete += item.length
+              deleted.add(item)
+            } // else nop
+          } else {
+            if (this.adds(item)) {
+              if (lastOp === null || lastOp.insert === undefined) {
+                packOp()
+                lastOp = { insert: [] }
+              }
+              lastOp.insert = lastOp.insert.concat(item.content.getContent())
+              added.add(item)
+            } else {
+              if (lastOp === null || lastOp.retain === undefined) {
+                packOp()
+                lastOp = { retain: 0 }
+              }
+              lastOp.retain += item.length
+            }
+          }
+        }
+        if (lastOp !== null && lastOp.retain === undefined) {
+          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)
+  }
 }
 
 /**

src/utils/encoding.js

@@ -1,47 +1,39 @@
 
 /**
  * @module encoding
+ *
+ * We use the first five bits in the info flag for determining the type of the struct.
+ *
+ * 0: GC
+ * 1: Item with Deleted content
+ * 2: Item with JSON content
+ * 3: Item with Binary content
+ * 4: Item with String content
+ * 5: Item with Embed content (for richtext content)
+ * 6: Item with Format content (a formatting marker for richtext content)
+ * 7: Item with Type
  */
 
 import {
   findIndexSS,
   GCRef,
-  ItemBinaryRef,
-  ItemDeletedRef,
-  ItemEmbedRef,
-  ItemFormatRef,
-  ItemJSONRef,
-  ItemStringRef,
-  ItemTypeRef,
+  ItemRef,
   writeID,
   createID,
   readID,
   getState,
   getStateVector,
-  readDeleteSet,
+  readAndApplyDeleteSet,
   writeDeleteSet,
   createDeleteSetFromStructStore,
-  Doc, Transaction, AbstractStruct, AbstractStructRef, StructStore, ID // eslint-disable-line
+  transact,
+  Doc, Transaction, AbstractStruct, StructStore, ID // 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'
 
-/**
- * @private
- */
-export const structRefs = [
-  GCRef,
-  ItemBinaryRef,
-  ItemDeletedRef,
-  ItemEmbedRef,
-  ItemFormatRef,
-  ItemJSONRef,
-  ItemStringRef,
-  ItemTypeRef
-]
-
 /**
  * @param {encoding.Encoder} encoder
  * @param {Array<AbstractStruct>} structs All structs by `client`
@@ -68,19 +60,19 @@ const writeStructs = (encoder, structs, client, clock) => {
  * @param {decoding.Decoder} decoder
  * @param {number} numOfStructs
  * @param {ID} nextID
- * @return {Array<AbstractStructRef>}
+ * @return {Array<GCRef|ItemRef>}
  *
  * @private
  * @function
  */
 const readStructRefs = (decoder, numOfStructs, nextID) => {
   /**
-   * @type {Array<AbstractStructRef>}
+   * @type {Array<GCRef|ItemRef>}
    */
   const refs = []
   for (let i = 0; i < numOfStructs; i++) {
     const info = decoding.readUint8(decoder)
-    const ref = new structRefs[binary.BITS5 & info](decoder, nextID, info)
+    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)
   }
@@ -119,14 +111,14 @@ export const writeClientsStructs = (encoder, store, _sm) => {
 
 /**
  * @param {decoding.Decoder} decoder The decoder object to read data from.
- * @return {Map<number,Array<AbstractStructRef>>}
+ * @return {Map<number,Array<GCRef|ItemRef>>}
  *
  * @private
  * @function
  */
 export const readClientsStructRefs = decoder => {
   /**
-   * @type {Map<number,Array<AbstractStructRef>>}
+   * @type {Map<number,Array<GCRef|ItemRef>>}
    */
   const clientRefs = new Map()
   const numOfStateUpdates = decoding.readVarUint(decoder)
@@ -239,7 +231,7 @@ export const tryResumePendingDeleteReaders = (transaction, store) => {
   const pendingReaders = store.pendingDeleteReaders
   store.pendingDeleteReaders = []
   for (let i = 0; i < pendingReaders.length; i++) {
-    readDeleteSet(pendingReaders[i], transaction, store)
+    readAndApplyDeleteSet(pendingReaders[i], transaction, store)
   }
 }
 
@@ -254,7 +246,7 @@ export const writeStructsFromTransaction = (encoder, transaction) => writeClient
 
 /**
  * @param {StructStore} store
- * @param {Map<number, Array<AbstractStructRef>>} clientsStructsRefs
+ * @param {Map<number, Array<GCRef|ItemRef>>} clientsStructsRefs
  *
  * @private
  * @function
@@ -308,10 +300,10 @@ export const readStructs = (decoder, transaction, store) => {
  * @function
  */
 export const readUpdate = (decoder, ydoc, transactionOrigin) =>
-  ydoc.transact(transaction => {
+  transact(ydoc, transaction => {
     readStructs(decoder, transaction, ydoc.store)
-    readDeleteSet(decoder, transaction, ydoc.store)
-  }, transactionOrigin)
+    readAndApplyDeleteSet(decoder, transaction, ydoc.store)
+  }, transactionOrigin, false)
 
 /**
  * Apply a document update created by, for example, `y.on('update', update => ..)` or `update = encodeStateAsUpdate()`.
@@ -390,6 +382,22 @@ export const readStateVector = decoder => {
  */
 export const decodeStateVector = decodedState => readStateVector(decoding.createDecoder(decodedState))
 
+/**
+ * Write State Vector to `lib0/encoding.js#Encoder`.
+ *
+ * @param {encoding.Encoder} 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)
+  })
+  return encoder
+}
+
 /**
  * Write State Vector to `lib0/encoding.js#Encoder`.
  *
@@ -398,16 +406,7 @@ export const decodeStateVector = decodedState => readStateVector(decoding.create
  *
  * @function
  */
-export const writeDocumentStateVector = (encoder, doc) => {
-  encoding.writeVarUint(encoder, doc.store.clients.size)
-  doc.store.clients.forEach((structs, client) => {
-    const struct = structs[structs.length - 1]
-    const id = struct.id
-    encoding.writeVarUint(encoder, id.client)
-    encoding.writeVarUint(encoder, id.clock + struct.length)
-  })
-  return encoder
-}
+export const writeDocumentStateVector = (encoder, doc) => writeStateVector(encoder, getStateVector(doc.store))
 
 /**
  * Encode State as Uint8Array.

src/utils/isParentOf.js

@@ -1,22 +1,22 @@
 
-import { AbstractType } from '../internals.js' // eslint-disable-line
+import { AbstractType, Item } from '../internals.js' // eslint-disable-line
 
 /**
  * Check if `parent` is a parent of `child`.
  *
  * @param {AbstractType<any>} parent
- * @param {AbstractType<any>} child
+ * @param {Item|null} child
  * @return {Boolean} Whether `parent` is a parent of `child`.
  *
  * @private
  * @function
  */
 export const isParentOf = (parent, child) => {
-  while (child._item !== null) {
-    if (child === parent) {
+  while (child !== null) {
+    if (child.parent === parent) {
       return true
     }
-    child = child._item.parent
+    child = child.parent._item
   }
   return false
 }

tests/consistency.tests.js

@@ -0,0 +1,19 @@
+
+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/encoding.tests.js

@@ -1,36 +1,28 @@
 import * as t from 'lib0/testing.js'
 
 import {
-  structRefs,
-  structGCRefNumber,
-  structBinaryRefNumber,
-  structDeletedRefNumber,
-  structEmbedRefNumber,
-  structFormatRefNumber,
-  structJSONRefNumber,
-  structStringRefNumber,
-  structTypeRefNumber,
-  GCRef,
-  ItemBinaryRef,
-  ItemDeletedRef,
-  ItemEmbedRef,
-  ItemFormatRef,
-  ItemJSONRef,
-  ItemStringRef,
-  ItemTypeRef
+  contentRefs,
+  readContentBinary,
+  readContentDeleted,
+  readContentString,
+  readContentJSON,
+  readContentEmbed,
+  readContentType,
+  readContentFormat,
+  readContentAny
 } from '../src/internals.js'
 
 /**
  * @param {t.TestCase} tc
  */
 export const testStructReferences = tc => {
-  t.assert(structRefs.length === 8)
-  t.assert(structRefs[structGCRefNumber] === GCRef)
-  t.assert(structRefs[structBinaryRefNumber] === ItemBinaryRef)
-  t.assert(structRefs[structDeletedRefNumber] === ItemDeletedRef)
-  t.assert(structRefs[structEmbedRefNumber] === ItemEmbedRef)
-  t.assert(structRefs[structFormatRefNumber] === ItemFormatRef)
-  t.assert(structRefs[structJSONRefNumber] === ItemJSONRef)
-  t.assert(structRefs[structStringRefNumber] === ItemStringRef)
-  t.assert(structRefs[structTypeRefNumber] === ItemTypeRef)
+  t.assert(contentRefs.length === 9)
+  t.assert(contentRefs[1] === readContentDeleted)
+  t.assert(contentRefs[2] === readContentJSON) // TODO: deprecate content json?
+  t.assert(contentRefs[3] === readContentBinary)
+  t.assert(contentRefs[4] === readContentString)
+  t.assert(contentRefs[5] === readContentEmbed)
+  t.assert(contentRefs[6] === readContentFormat)
+  t.assert(contentRefs[7] === readContentType)
+  t.assert(contentRefs[8] === readContentAny)
 }

tests/index.js

@@ -4,6 +4,8 @@ import * as map from './y-map.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 { runTests } from 'lib0/testing.js'
 import { isBrowser, isNode } from 'lib0/environment.js'
@@ -13,7 +15,7 @@ if (isBrowser) {
   log.createVConsole(document.body)
 }
 runTests({
-  map, array, text, xml, encoding
+  map, array, text, xml, consistency, encoding, undoredo
 }).then(success => {
   /* istanbul ignore next */
   if (isNode) {

tests/testHelper.js

@@ -3,8 +3,8 @@ import * as Y from '../src/index.js'
 import {
   createDeleteSetFromStructStore,
   getStateVector,
-  AbstractItem,
-  DeleteSet, StructStore, Doc // eslint-disable-line
+  Item,
+  DeleteItem, DeleteSet, StructStore, Doc // eslint-disable-line
 } from '../src/internals.js'
 
 import * as t from 'lib0/testing.js'
@@ -12,6 +12,8 @@ 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'
 
 /**
  * @param {TestYInstance} y // publish message created by `y` to all other online clients
@@ -54,6 +56,7 @@ export class TestYInstance extends Doc {
     })
     this.connect()
   }
+
   /**
    * Disconnect from TestConnector.
    */
@@ -61,6 +64,7 @@ export class TestYInstance extends Doc {
     this.receiving = new Map()
     this.tc.onlineConns.delete(this)
   }
+
   /**
    * Append yourself to the list of known Y instances in testconnector.
    * Also initiate sync with all clients.
@@ -82,6 +86,7 @@ export class TestYInstance extends Doc {
       })
     }
   }
+
   /**
    * Receive a message from another client. This message is only appended to the list of receiving messages.
    * TestConnector decides when this client actually reads this message.
@@ -123,6 +128,7 @@ export class TestConnector {
      */
     this.prng = gen
   }
+
   /**
    * Create a new Y instance and add it to the list of connections
    * @param {number} clientID
@@ -130,6 +136,7 @@ export class TestConnector {
   createY (clientID) {
     return new TestYInstance(this, clientID)
   }
+
   /**
    * Choose random connection and flush a random message from a random sender.
    *
@@ -161,6 +168,7 @@ export class TestConnector {
     }
     return false
   }
+
   /**
    * @return {boolean} True iff this function actually flushed something
    */
@@ -171,16 +179,20 @@ export class TestConnector {
     }
     return didSomething
   }
+
   reconnectAll () {
     this.allConns.forEach(conn => conn.connect())
   }
+
   disconnectAll () {
     this.allConns.forEach(conn => conn.disconnect())
   }
+
   syncAll () {
     this.reconnectAll()
     this.flushAllMessages()
   }
+
   /**
    * @return {boolean} Whether it was possible to disconnect a randon connection.
    */
@@ -191,6 +203,7 @@ export class TestConnector {
     prng.oneOf(this.prng, Array.from(this.onlineConns)).disconnect()
     return true
   }
+
   /**
    * @return {boolean} Whether it was possible to reconnect a random connection.
    */
@@ -240,8 +253,7 @@ export const init = (tc, { users = 5 } = {}, initTestObject) => {
   }
   testConnector.syncAll()
   result.testObjects = result.users.map(initTestObject || (() => null))
-  // @ts-ignore
-  return result
+  return /** @type {any} */ (result)
 }
 
 /**
@@ -256,7 +268,7 @@ export const init = (tc, { users = 5 } = {}, initTestObject) => {
 export const compare = users => {
   users.forEach(u => u.connect())
   while (users[0].tc.flushAllMessages()) {}
-  const userArrayValues = users.map(u => u.getArray('array').toJSON().map(val => JSON.stringify(val)))
+  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())
@@ -265,13 +277,27 @@ export const compare = users => {
     t.assert(u.store.pendingStack.length === 0)
     t.assert(u.store.pendingClientsStructRefs.size === 0)
   }
+  // Test Array iterator
+  t.compare(users[0].getArray('array').toArray(), Array.from(users[0].getArray('array')))
+  // Test Map iterator
+  const ymapkeys = Array.from(users[0].getMap('map').keys())
+  t.assert(ymapkeys.length === Object.keys(userMapValues[0]).length)
+  ymapkeys.forEach(key => t.assert(object.hasProperty(userMapValues[0], key)))
+  /**
+   * @type {Object<string,any>}
+   */
+  const mapRes = {}
+  for (const [k, v] of users[0].getMap('map')) {
+    mapRes[k] = v instanceof Y.AbstractType ? v.toJSON() : v
+  }
+  t.compare(userMapValues[0], mapRes)
+  // Compare all users
   for (let i = 0; i < users.length - 1; i++) {
     t.compare(userArrayValues[i].length, users[i].getArray('array').length)
     t.compare(userArrayValues[i], userArrayValues[i + 1])
     t.compare(userMapValues[i], userMapValues[i + 1])
     t.compare(userXmlValues[i], userXmlValues[i + 1])
-    // @ts-ignore
-    t.compare(userTextValues[i].map(a => a.insert).join('').length, users[i].getText('text').length)
+    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))
@@ -281,8 +307,8 @@ export const compare = users => {
 }
 
 /**
- * @param {AbstractItem?} a
- * @param {AbstractItem?} b
+ * @param {Item?} a
+ * @param {Item?} b
  * @return {boolean}
  */
 export const compareItemIDs = (a, b) => a === b || (a !== null && b != null && Y.compareIDs(a.id, b.id))
@@ -294,11 +320,10 @@ export const compareItemIDs = (a, b) => a === b || (a !== null && b != null && Y
 export const compareStructStores = (ss1, ss2) => {
   t.assert(ss1.clients.size === ss2.clients.size)
   for (const [client, structs1] of ss1.clients) {
-    const structs2 = ss2.clients.get(client)
+    const structs2 = /** @type {Array<Y.AbstractStruct>} */ (ss2.clients.get(client))
     t.assert(structs2 !== undefined && structs1.length === structs2.length)
     for (let i = 0; i < structs1.length; i++) {
       const s1 = structs1[i]
-      // @ts-ignore
       const s2 = structs2[i]
       // checks for abstract struct
       if (
@@ -309,9 +334,9 @@ export const compareStructStores = (ss1, ss2) => {
       ) {
         t.fail('Structs dont match')
       }
-      if (s1 instanceof AbstractItem) {
+      if (s1 instanceof Item) {
         if (
-          !(s2 instanceof AbstractItem) ||
+          !(s2 instanceof 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) ||
@@ -337,11 +362,10 @@ export const compareStructStores = (ss1, ss2) => {
 export const compareDS = (ds1, ds2) => {
   t.assert(ds1.clients.size === ds2.clients.size)
   for (const [client, deleteItems1] of ds1.clients) {
-    const deleteItems2 = ds2.clients.get(client)
+    const deleteItems2 = /** @type {Array<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]
-      // @ts-ignore
       const di2 = deleteItems2[i]
       if (di1.clock !== di2.clock || di1.len !== di2.len) {
         t.fail('DeleteSets dont match')
@@ -366,7 +390,7 @@ export const compareDS = (ds1, ds2) => {
  */
 export const applyRandomTests = (tc, mods, iterations, initTestObject) => {
   const gen = tc.prng
-  const result = init(tc, { users: 5 }, initTestObject || (() => null))
+  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) {

tests/undo-redo.tests.js

@@ -0,0 +1,248 @@
+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'
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testUndoText = tc => {
+  const { testConnector, text0, text1 } = init(tc, { users: 3 })
+  const undoManager = new UndoManager(text0)
+
+  // items that are added & deleted in the same transaction won't be undo
+  text0.insert(0, 'test')
+  text0.delete(0, 4)
+  undoManager.undo()
+  t.assert(text0.toString() === '')
+
+  // follow redone items
+  text0.insert(0, 'a')
+  undoManager.stopCapturing()
+  text0.delete(0, 1)
+  undoManager.stopCapturing()
+  undoManager.undo()
+  t.assert(text0.toString() === 'a')
+  undoManager.undo()
+  t.assert(text0.toString() === '')
+
+  text0.insert(0, 'abc')
+  text1.insert(0, 'xyz')
+  testConnector.syncAll()
+  undoManager.undo()
+  t.assert(text0.toString() === 'xyz')
+  undoManager.redo()
+  t.assert(text0.toString() === 'abcxyz')
+  testConnector.syncAll()
+  text1.delete(0, 1)
+  testConnector.syncAll()
+  undoManager.undo()
+  t.assert(text0.toString() === 'xyz')
+  undoManager.redo()
+  t.assert(text0.toString() === 'bcxyz')
+  // test marks
+  text0.format(1, 3, { bold: true })
+  t.compare(text0.toDelta(), [{ insert: 'b' }, { insert: 'cxy', attributes: { bold: true } }, { insert: 'z' }])
+  undoManager.undo()
+  t.compare(text0.toDelta(), [{ insert: 'bcxyz' }])
+  undoManager.redo()
+  t.compare(text0.toDelta(), [{ insert: 'b' }, { insert: 'cxy', attributes: { bold: true } }, { insert: 'z' }])
+}
+
+/**
+ * @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)
+  map0.set('a', 1)
+  undoManager.undo()
+  t.assert(map0.get('a') === 0)
+  undoManager.redo()
+  t.assert(map0.get('a') === 1)
+  // testing sub-types and if it can restore a whole type
+  const subType = new Y.Map()
+  map0.set('a', subType)
+  subType.set('x', 42)
+  t.compare(map0.toJSON(), /** @type {any} */ ({ a: { x: 42 } }))
+  undoManager.undo()
+  t.assert(map0.get('a') === 1)
+  undoManager.redo()
+  t.compare(map0.toJSON(), /** @type {any} */ ({ a: { x: 42 } }))
+  testConnector.syncAll()
+  // if content is overwritten by another user, undo operations should be skipped
+  map1.set('a', 44)
+  testConnector.syncAll()
+  undoManager.undo()
+  t.assert(map0.get('a') === 44)
+  undoManager.redo()
+  t.assert(map0.get('a') === 44)
+
+  // test setting value multiple times
+  map0.set('b', 'initial')
+  undoManager.stopCapturing()
+  map0.set('b', 'val1')
+  map0.set('b', 'val2')
+  undoManager.stopCapturing()
+  undoManager.undo()
+  t.assert(map0.get('b') === 'initial')
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testUndoArray = tc => {
+  const { testConnector, array0, array1 } = init(tc, { users: 3 })
+  const undoManager = new UndoManager(array0)
+  array0.insert(0, [1, 2, 3])
+  array1.insert(0, [4, 5, 6])
+  testConnector.syncAll()
+  t.compare(array0.toArray(), [1, 2, 3, 4, 5, 6])
+  undoManager.undo()
+  t.compare(array0.toArray(), [4, 5, 6])
+  undoManager.redo()
+  t.compare(array0.toArray(), [1, 2, 3, 4, 5, 6])
+  testConnector.syncAll()
+  array1.delete(0, 1) // user1 deletes [1]
+  testConnector.syncAll()
+  undoManager.undo()
+  t.compare(array0.toArray(), [4, 5, 6])
+  undoManager.redo()
+  t.compare(array0.toArray(), [2, 3, 4, 5, 6])
+  array0.delete(0, 5)
+  // test nested structure
+  const ymap = new Y.Map()
+  array0.insert(0, [ymap])
+  t.compare(array0.toJSON(), [{}])
+  undoManager.stopCapturing()
+  ymap.set('a', 1)
+  t.compare(array0.toJSON(), [{ a: 1 }])
+  undoManager.undo()
+  t.compare(array0.toJSON(), [{}])
+  undoManager.undo()
+  t.compare(array0.toJSON(), [2, 3, 4, 5, 6])
+  undoManager.redo()
+  t.compare(array0.toJSON(), [{}])
+  undoManager.redo()
+  t.compare(array0.toJSON(), [{ a: 1 }])
+  testConnector.syncAll()
+  array1.get(0).set('b', 2)
+  testConnector.syncAll()
+  t.compare(array0.toJSON(), [{ a: 1, b: 2 }])
+  undoManager.undo()
+  t.compare(array0.toJSON(), [{ b: 2 }])
+  undoManager.undo()
+  t.compare(array0.toJSON(), [2, 3, 4, 5, 6])
+  undoManager.redo()
+  t.compare(array0.toJSON(), [{ b: 2 }])
+  undoManager.redo()
+  t.compare(array0.toJSON(), [{ a: 1, b: 2 }])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testUndoXml = tc => {
+  const { xml0 } = init(tc, { users: 3 })
+  const undoManager = new UndoManager(xml0)
+  const child = new Y.XmlElement('p')
+  xml0.insert(0, [child])
+  const textchild = new Y.XmlText('content')
+  child.insert(0, [textchild])
+  t.assert(xml0.toString() === '<undefined><p>content</p></undefined>')
+  // format textchild and revert that change
+  undoManager.stopCapturing()
+  textchild.format(3, 4, { bold: {} })
+  t.assert(xml0.toString() === '<undefined><p>con<bold>tent</bold></p></undefined>')
+  undoManager.undo()
+  t.assert(xml0.toString() === '<undefined><p>content</p></undefined>')
+  undoManager.redo()
+  t.assert(xml0.toString() === '<undefined><p>con<bold>tent</bold></p></undefined>')
+  xml0.delete(0, 1)
+  t.assert(xml0.toString() === '<undefined></undefined>')
+  undoManager.undo()
+  t.assert(xml0.toString() === '<undefined><p>con<bold>tent</bold></p></undefined>')
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testUndoEvents = tc => {
+  const { text0 } = init(tc, { users: 3 })
+  const undoManager = new UndoManager(text0)
+  let counter = 0
+  let receivedMetadata = -1
+  undoManager.on('stack-item-added', /** @param {any} event */ event => {
+    t.assert(event.type != null)
+    event.stackItem.meta.set('test', counter++)
+  })
+  undoManager.on('stack-item-popped', /** @param {any} event */ event => {
+    t.assert(event.type != null)
+    receivedMetadata = event.stackItem.meta.get('test')
+  })
+  text0.insert(0, 'abc')
+  undoManager.undo()
+  t.assert(receivedMetadata === 0)
+  undoManager.redo()
+  t.assert(receivedMetadata === 1)
+}
+
+/**
+ * @param {t.TestCase} 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]) })
+  users[0].transact(() => {
+    text0.insert(0, 'abc')
+  }, 42)
+  t.assert(text0.toString() === 'abc')
+  undoManager.undo()
+  t.assert(text0.toString() === '')
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testTypeScope = tc => {
+  const { array0 } = init(tc, { users: 3 })
+  // only track origins that are numbers
+  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])
+  text1.insert(0, 'abc')
+  t.assert(undoManager.undoStack.length === 0)
+  t.assert(undoManagerBoth.undoStack.length === 1)
+  t.assert(text1.toString() === 'abc')
+  undoManager.undo()
+  t.assert(text1.toString() === 'abc')
+  undoManagerBoth.undo()
+  t.assert(text1.toString() === '')
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testUndoDeleteFilter = tc => {
+  /**
+   * @type {Array<Y.Map<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 map0 = new Y.Map()
+  map0.set('hi', 1)
+  const map1 = new Y.Map()
+  array0.insert(0, [map0, map1])
+  undoManager.undo()
+  t.assert(array0.length === 1)
+  array0.get(0)
+  t.assert(Array.from(array0.get(0).keys()).length === 1)
+}

tests/y-array.tests.js

@@ -1,8 +1,9 @@
-import { init, compare, applyRandomTests, TestYInstance } from './testHelper.js' // eslint-disable-line
+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'
 
 /**
  * @param {t.TestCase} tc
@@ -191,6 +192,33 @@ export const testInsertAndDeleteEventsForTypes = tc => {
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testChangeEvent = tc => {
+  const { array0, users } = init(tc, { users: 2 })
+  /**
+   * @type {any}
+   */
+  let changes = null
+  array0.observe(e => {
+    changes = e.changes
+  })
+  const newArr = new Y.Array()
+  array0.insert(0, [newArr, 4, 'dtrn'])
+  t.assert(changes !== null && changes.added.size === 2 && changes.deleted.size === 0)
+  t.compare(changes.delta, [{ insert: [newArr, 4, 'dtrn'] }])
+  changes = null
+  array0.delete(0, 2)
+  t.assert(changes !== null && changes.added.size === 0 && changes.deleted.size === 2)
+  t.compare(changes.delta, [{ delete: 2 }])
+  changes = null
+  array0.insert(1, [0.1])
+  t.assert(changes !== null && changes.added.size === 1 && changes.deleted.size === 0)
+  t.compare(changes.delta, [{ retain: 1 }, { insert: [0.1] }])
+  compare(users)
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -199,7 +227,7 @@ export const testInsertAndDeleteEventsForTypes2 = tc => {
   /**
    * @type {Array<Object<string,any>>}
    */
-  let events = []
+  const events = []
   array0.observe(e => {
     events.push(e)
   })
@@ -210,6 +238,24 @@ export const testInsertAndDeleteEventsForTypes2 = tc => {
   compare(users)
 }
 
+/**
+ * This issue has been reported here https://github.com/yjs/yjs/issues/155
+ * @param {t.TestCase} tc
+ */
+export const testNewChildDoesNotEmitEventInTransaction = tc => {
+  const { array0, users } = init(tc, { users: 2 })
+  let fired = false
+  users[0].transact(() => {
+    const newMap = new Y.Map()
+    newMap.observe(() => {
+      fired = true
+    })
+    array0.insert(0, [newMap])
+    newMap.set('tst', 42)
+  })
+  t.assert(!fired, 'Event does not trigger')
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -272,7 +318,7 @@ export const testIteratingArrayContainingTypes = tc => {
     arr.push([map])
   }
   let cnt = 0
-  for (let item of arr) {
+  for (const item of arr) {
     t.assert(item.get('value') === cnt++, 'value is correct')
   }
   y.destroy()
@@ -282,7 +328,7 @@ let _uniqueNumber = 0
 const getUniqueNumber = () => _uniqueNumber++
 
 /**
- * @type {Array<function(TestYInstance,prng.PRNG):void>}
+ * @type {Array<function(Doc,prng.PRNG,any):void>}
  */
 const arrayTransactions = [
   function insert (user, gen) {
@@ -317,12 +363,12 @@ const arrayTransactions = [
     var 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))
+      var delLength = prng.int31(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))
+          delLength = prng.int31(gen, 0, math.min(2, type.length - somePos))
           type.delete(somePos, delLength)
         }
       } else {

tests/y-map.tests.js

@@ -1,4 +1,4 @@
-import { init, compare, applyRandomTests, TestYInstance } from './testHelper.js' // eslint-disable-line
+import { init, compare, applyRandomTests, Doc } from './testHelper.js' // eslint-disable-line
 
 import {
   compareIDs
@@ -66,7 +66,7 @@ export const testGetAndSetOfMapProperty = tc => {
 
   testConnector.flushAllMessages()
 
-  for (let user of users) {
+  for (const user of users) {
     const u = user.getMap('map')
     t.compare(u.get('stuff'), 'stuffy')
     t.assert(u.get('undefined') === undefined, 'undefined')
@@ -108,7 +108,7 @@ export const testGetAndSetOfMapPropertySyncs = tc => {
   map0.set('stuff', 'stuffy')
   t.compare(map0.get('stuff'), 'stuffy')
   testConnector.flushAllMessages()
-  for (let user of users) {
+  for (const user of users) {
     var u = user.getMap('map')
     t.compare(u.get('stuff'), 'stuffy')
   }
@@ -123,7 +123,7 @@ export const testGetAndSetOfMapPropertyWithConflict = tc => {
   map0.set('stuff', 'c0')
   map1.set('stuff', 'c1')
   testConnector.flushAllMessages()
-  for (let user of users) {
+  for (const user of users) {
     var u = user.getMap('map')
     t.compare(u.get('stuff'), 'c1')
   }
@@ -139,7 +139,7 @@ export const testGetAndSetAndDeleteOfMapProperty = tc => {
   map1.set('stuff', 'c1')
   map1.delete('stuff')
   testConnector.flushAllMessages()
-  for (let user of users) {
+  for (const user of users) {
     var u = user.getMap('map')
     t.assert(u.get('stuff') === undefined)
   }
@@ -156,7 +156,7 @@ export const testGetAndSetOfMapPropertyWithThreeConflicts = tc => {
   map1.set('stuff', 'c2')
   map2.set('stuff', 'c3')
   testConnector.flushAllMessages()
-  for (let user of users) {
+  for (const user of users) {
     var u = user.getMap('map')
     t.compare(u.get('stuff'), 'c3')
   }
@@ -179,7 +179,7 @@ export const testGetAndSetAndDeleteOfMapPropertyWithThreeConflicts = tc => {
   map3.set('stuff', 'c3')
   map3.delete('stuff')
   testConnector.flushAllMessages()
-  for (let user of users) {
+  for (const user of users) {
     var u = user.getMap('map')
     t.assert(u.get('stuff') === undefined)
   }
@@ -292,6 +292,104 @@ export const testThrowsAddAndUpdateAndDeleteEvents = tc => {
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testChangeEvent = tc => {
+  const { map0, users } = init(tc, { users: 2 })
+  /**
+   * @type {any}
+   */
+  let changes = null
+  /**
+   * @type {any}
+   */
+  let keyChange = null
+  map0.observe(e => {
+    changes = e.changes
+  })
+  map0.set('a', 1)
+  keyChange = changes.keys.get('a')
+  t.assert(changes !== null && keyChange.action === 'add' && keyChange.oldValue === undefined)
+  map0.set('a', 2)
+  keyChange = changes.keys.get('a')
+  t.assert(changes !== null && keyChange.action === 'update' && keyChange.oldValue === 1)
+  users[0].transact(() => {
+    map0.set('a', 3)
+    map0.set('a', 4)
+  })
+  keyChange = changes.keys.get('a')
+  t.assert(changes !== null && keyChange.action === 'update' && keyChange.oldValue === 2)
+  users[0].transact(() => {
+    map0.set('b', 1)
+    map0.set('b', 2)
+  })
+  keyChange = changes.keys.get('b')
+  t.assert(changes !== null && keyChange.action === 'add' && keyChange.oldValue === undefined)
+  users[0].transact(() => {
+    map0.set('c', 1)
+    map0.delete('c')
+  })
+  t.assert(changes !== null && changes.keys.size === 0)
+  users[0].transact(() => {
+    map0.set('d', 1)
+    map0.set('d', 2)
+  })
+  keyChange = changes.keys.get('d')
+  t.assert(changes !== null && keyChange.action === 'add' && keyChange.oldValue === undefined)
+  compare(users)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testYmapEventExceptionsShouldCompleteTransaction = tc => {
+  const doc = new Y.Doc()
+  const map = doc.getMap('map')
+
+  let updateCalled = false
+  let throwingObserverCalled = false
+  let throwingDeepObserverCalled = false
+  doc.on('update', () => {
+    updateCalled = true
+  })
+
+  const throwingObserver = () => {
+    throwingObserverCalled = true
+    throw new Error('Failure')
+  }
+
+  const throwingDeepObserver = () => {
+    throwingDeepObserverCalled = true
+    throw new Error('Failure')
+  }
+
+  map.observe(throwingObserver)
+  map.observeDeep(throwingDeepObserver)
+
+  t.fails(() => {
+    map.set('y', '2')
+  })
+
+  t.assert(updateCalled)
+  t.assert(throwingObserverCalled)
+  t.assert(throwingDeepObserverCalled)
+
+  // check if it works again
+  updateCalled = false
+  throwingObserverCalled = false
+  throwingDeepObserverCalled = false
+  t.fails(() => {
+    map.set('z', '3')
+  })
+
+  t.assert(updateCalled)
+  t.assert(throwingObserverCalled)
+  t.assert(throwingDeepObserverCalled)
+
+  t.assert(map.get('z') === '3')
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -328,16 +426,16 @@ export const testYmapEventHasCorrectValueWhenSettingAPrimitiveFromOtherUser = tc
 }
 
 /**
- * @type {Array<function(TestYInstance,prng.PRNG):void>}
+ * @type {Array<function(Doc,prng.PRNG):void>}
  */
 const mapTransactions = [
   function set (user, gen) {
-    let key = prng.oneOf(gen, ['one', 'two'])
+    const key = prng.oneOf(gen, ['one', 'two'])
     var value = prng.utf16String(gen)
     user.getMap('map').set(key, value)
   },
   function setType (user, gen) {
-    let key = prng.oneOf(gen, ['one', 'two'])
+    const key = prng.oneOf(gen, ['one', 'two'])
     var type = prng.oneOf(gen, [new Y.Array(), new Y.Map()])
     user.getMap('map').set(key, type)
     if (type instanceof Y.Array) {
@@ -347,7 +445,7 @@ const mapTransactions = [
     }
   },
   function _delete (user, gen) {
-    let key = prng.oneOf(gen, ['one', 'two'])
+    const key = prng.oneOf(gen, ['one', 'two'])
     user.getMap('map').delete(key)
   }
 ]

tests/y-text.tests.js

@@ -1,6 +1,6 @@
-import { init, compare } from './testHelper.js'
-
+import * as Y from './testHelper.js'
 import * as t from 'lib0/testing.js'
+const { init, compare } = Y
 
 /**
  * @param {t.TestCase} tc
@@ -63,7 +63,7 @@ export const testBasicFormat = tc => {
   t.compare(text0.toDelta(), [{ insert: 'zb', attributes: { bold: true } }])
   t.compare(delta, [{ insert: 'z', attributes: { bold: true } }])
   // @ts-ignore
-  t.assert(text0._start.right.right.right.string === 'b', 'Does not insert duplicate attribute marker')
+  t.assert(text0._start.right.right.right.content.str === 'b', 'Does not insert duplicate attribute marker')
   text0.insert(0, 'y')
   t.assert(text0.toString() === 'yzb')
   t.compare(text0.toDelta(), [{ insert: 'y' }, { insert: 'zb', attributes: { bold: true } }])
@@ -74,3 +74,109 @@ export const testBasicFormat = tc => {
   t.compare(delta, [{ retain: 1 }, { retain: 1, attributes: { bold: null } }])
   compare(users)
 }
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testGetDeltaWithEmbeds = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  text0.applyDelta([{
+    insert: { linebreak: 's' }
+  }])
+  t.compare(text0.toDelta(), [{
+    insert: { linebreak: 's' }
+  }])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSnapshot = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  const doc0 = /** @type {Y.Doc} */ (text0.doc)
+  doc0.gc = false
+  text0.applyDelta([{
+    insert: 'abcd'
+  }])
+  const snapshot1 = Y.snapshot(doc0)
+  text0.applyDelta([{
+    retain: 1
+  }, {
+    insert: 'x'
+  }, {
+    delete: 1
+  }])
+  const snapshot2 = Y.snapshot(doc0)
+  text0.applyDelta([{
+    retain: 2
+  }, {
+    delete: 3
+  }, {
+    insert: 'x'
+  }, {
+    delete: 1
+  }])
+  const state1 = text0.toDelta(snapshot1)
+  t.compare(state1, [{ insert: 'abcd' }])
+  const state2 = text0.toDelta(snapshot2)
+  t.compare(state2, [{ insert: 'axcd' }])
+  const state2Diff = text0.toDelta(snapshot2, snapshot1)
+  // @ts-ignore Remove userid info
+  state2Diff.forEach(v => {
+    if (v.attributes && v.attributes.ychange) {
+      delete v.attributes.ychange.user
+    }
+  })
+  t.compare(state2Diff, [{ insert: 'a' }, { insert: 'x', attributes: { ychange: { type: 'added' } } }, { insert: 'b', attributes: { ychange: { type: 'removed' } } }, { insert: 'cd' }])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSnapshotDeleteAfter = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  const doc0 = /** @type {Y.Doc} */ (text0.doc)
+  doc0.gc = false
+  text0.applyDelta([{
+    insert: 'abcd'
+  }])
+  const snapshot1 = Y.snapshot(doc0)
+  text0.applyDelta([{
+    retain: 4
+  }, {
+    insert: 'e'
+  }])
+  const state1 = text0.toDelta(snapshot1)
+  t.compare(state1, [{ insert: 'abcd' }])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testToJson = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  text0.insert(0, 'abc', { bold: true })
+  t.assert(text0.toJSON() === 'abc', 'toJSON returns the unformatted text')
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testToDeltaEmbedAttributes = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  text0.insert(0, 'ab', { bold: true })
+  text0.insertEmbed(1, { image: 'imageSrc.png' }, { width: 100 })
+  const delta0 = text0.toDelta()
+  t.compare(delta0, [{ insert: 'a', attributes: { bold: true } }, { insert: { image: 'imageSrc.png' }, attributes: { width: 100 } }, { insert: 'b', attributes: { bold: true } }])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testToDeltaEmbedNoAttributes = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  text0.insert(0, 'ab', { bold: true })
+  text0.insertEmbed(1, { image: 'imageSrc.png' })
+  const delta0 = text0.toDelta()
+  t.compare(delta0, [{ insert: 'a', attributes: { bold: true } }, { insert: { image: 'imageSrc.png' } }, { insert: 'b', attributes: { bold: true } }], 'toDelta does not set attributes key when no attributes are present')
+}

tests/y-xml.tests.js

@@ -60,13 +60,13 @@ export const testEvents = tc => {
  */
 export const testTreewalker = tc => {
   const { users, xml0 } = init(tc, { users: 3 })
-  let paragraph1 = new Y.XmlElement('p')
-  let paragraph2 = new Y.XmlElement('p')
-  let text1 = new Y.XmlText('init')
-  let text2 = new Y.XmlText('text')
+  const paragraph1 = new Y.XmlElement('p')
+  const paragraph2 = new Y.XmlElement('p')
+  const text1 = new Y.XmlText('init')
+  const text2 = new Y.XmlText('text')
   paragraph1.insert(0, [text1, text2])
   xml0.insert(0, [paragraph1, paragraph2, new Y.XmlElement('img')])
-  let allParagraphs = xml0.querySelectorAll('p')
+  const allParagraphs = xml0.querySelectorAll('p')
   t.assert(allParagraphs.length === 2, 'found exactly two paragraphs')
   t.assert(allParagraphs[0] === paragraph1, 'querySelectorAll found paragraph1')
   t.assert(allParagraphs[1] === paragraph2, 'querySelectorAll found paragraph2')

tsconfig.json

@@ -6,15 +6,15 @@
     "allowJs": true,                       /* Allow javascript files to be compiled. */
     "checkJs": true,                       /* Report errors in .js files. */
     // "jsx": "preserve",                     /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
-    // "declaration": true,                   /* Generates corresponding '.d.ts' file. */
+    "declaration": true,                   /* Generates corresponding '.d.ts' file. */
     // "declarationMap": true,                /* Generates a sourcemap for each corresponding '.d.ts' file. */
     // "sourceMap": true,                     /* Generates corresponding '.map' file. */
-    // "outFile": "./",                       /* Concatenate and emit output to single file. */
-    // "outDir": "./build",                        /* Redirect output structure to the directory. */
-    // "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
+    // "outFile": "./dist/yjs.js",                       /* Concatenate and emit output to single file. */
+    "outDir": "./dist",                        /* Redirect output structure to the directory. */
+    "rootDir": "./",                       /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
     // "composite": true,                     /* Enable project compilation */
     // "removeComments": true,                /* Do not emit comments to output. */
-    "noEmit": true,                        /* Do not emit outputs. */
+    // "noEmit": true,                        /* Do not emit outputs. */
     // "importHelpers": true,                 /* Import emit helpers from 'tslib'. */
     // "downlevelIteration": true,            /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
     // "isolatedModules": true,               /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
@@ -22,6 +22,7 @@
     /* Strict Type-Checking Options */
     "strict": true,                           /* Enable all strict type-checking options. */
     "noImplicitAny": true,                 /* Raise error on expressions and declarations with an implied 'any' type. */
+    "emitDeclarationOnly": true,
     // "strictNullChecks": true,              /* Enable strict null checks. */
     // "strictFunctionTypes": true,           /* Enable strict checking of function types. */
     // "strictPropertyInitialization": true,  /* Enable strict checking of property initialization in classes. */
@@ -36,8 +37,10 @@
 
     /* Module Resolution Options */
     "moduleResolution": "node",            /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
-    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
-    // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
+    "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
+    "paths": {
+      "yjs": ["./src/index.js"]
+    },                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
     // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
     // "typeRoots": [],                       /* List of folders to include type definitions from. */
     // "types": [],                           /* Type declaration files to be included in compilation. */
@@ -54,9 +57,8 @@
     /* Experimental Options */
     // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
     // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */
-    "maxNodeModuleJsDepth": 5,
+    // "maxNodeModuleJsDepth": 0,
     // "types": ["./src/utils/typedefs.js"]
   },
-  "include": ["./src/**/*", "./tests/**/*"],
-  "exclude": ["../lib0/**/*", "node_modules/**/*", "dist", "dist/**/*.js"]
+  "include": ["./src/**/*.js", "./tests/**/*.js"]
 }