13.0.0-97

fix type error >= tsc@3.6
update lib0
2019-09-04 13:21:10 +02:00 · 2019-09-04 13:19:25 +02:00 · 2019-09-04 13:15:34 +02:00 · 2019-09-04 13:08:34 +02:00 · 2019-09-03 16:33:29 +02:00 · 2019-08-31 22:42:18 +02:00
19 changed files with 1661 additions and 1246 deletions
--- a/.jsdoc.json
+++ b/.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",
--- a/README.md
+++ b/README.md
--- a/README.v12.md
+++ b/README.v12.md
@@ -0,0 +1,305 @@
+
+# ![Yjs](https://user-images.githubusercontent.com/5553757/48975307-61efb100-f06d-11e8-9177-ee895e5916e5.png)
+
+Yjs is a framework for offline-first p2p shared editing on structured data like
+text, richtext, json, or XML. It is fairly easy to get started, as Yjs hides
+most of the complexity of concurrent editing. For additional information, demos,
+and tutorials visit [y-js.org](http://y-js.org/).
+
+:warning: Checkout the [v13 docs](./README.md) for the upcoming release :warning:
+
+### Extensions
+Yjs only knows how to resolve conflicts on shared data. You have to choose a ..
+
+* *Connector* - a communication protocol that propagates changes to the clients
+* *Database* - a database to store your changes
+* one or more *Types* - that represent the shared data
+
+Connectors, Databases, and Types are available as modules that extend Yjs. Here
+is a list of the modules we know of:
+
+##### Connectors
+
+|Name            | Description               |
+|----------------|-----------------------------------|
+|[webrtc](https://github.com/y-js/y-webrtc) | Propagate updates Browser2Browser via WebRTC|
+|[websockets](https://github.com/y-js/y-websockets-client) | Set up [a central server](https://github.com/y-js/y-websockets-client), and connect to it via websockets |
+|[xmpp](https://github.com/y-js/y-xmpp) | Propagate updates in a XMPP multi-user-chat room ([XEP-0045](http://xmpp.org/extensions/xep-0045.html))|
+|[ipfs](https://github.com/ipfs-labs/y-ipfs-connector) | Connector for the [Interplanetary File System](https://ipfs.io/)!|
+|[test](https://github.com/y-js/y-test) | A Connector for testing purposes. It is designed to simulate delays that happen in worst case scenarios|
+
+##### Database adapters
+
+|Name            | Description               |
+|----------------|-----------------------------------|
+|[memory](https://github.com/y-js/y-memory) | In-memory storage. |
+|[indexeddb](https://github.com/y-js/y-indexeddb) | Offline storage for the browser |
+|[leveldb](https://github.com/y-js/y-leveldb) | Persistent storage for node apps |
+
+##### Types
+
+| Name     | Description       |
+|----------|-------------------|
+|[map](https://github.com/y-js/y-map) | A shared Map implementation. Maps from text to any stringify-able object |
+|[array](https://github.com/y-js/y-array) | A shared Array implementation |
+|[xml](https://github.com/y-js/y-xml) | An implementation of the DOM. You can create a two way binding to Browser DOM objects |
+|[text](https://github.com/y-js/y-text) | Collaborate on text. Supports two way binding to the [Ace Editor](https://ace.c9.io), [CodeMirror](https://codemirror.net/), [Monaco](https://github.com/Microsoft/monaco-editor), textareas, input elements, and HTML elements (e.g. <*h1*>, or <*p*>) |
+|[richtext](https://github.com/y-js/y-richtext) | Collaborate on rich text. Supports two way binding to the [Quill Rich Text Editor](http://quilljs.com/)|
+
+##### Other
+
+| Name      | Description       |
+|-----------|-------------------|
+|[y-element](http://y-js.org/y-element/) | Yjs Polymer Element |
+
+## Use it!
+Install Yjs, and its modules with [bower](http://bower.io/), or
+[npm](https://www.npmjs.org/package/yjs).
+
+### Bower
+
+```
+bower install --save yjs y-array % add all y-* modules you want to use
+```
+You only need to include the `y.js` file. Yjs is able to automatically require
+missing modules.  
+```
+<script src="./bower_components/yjs/y.js"></script>
+```
+
+### CDN
+
+```
+<script src="https://cdn.jsdelivr.net/npm/yjs@12/dist/y.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-array@10/dist/y-array.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-websockets-client@8/dist/y-websockets-client.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-memory@8/dist/y-memory.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-map@10/dist/y-map.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-text@9/dist/y-text.js"></script>
+// ..
+// do the same for all modules you want to use
+```
+
+### Npm
+
+```
+npm install --save yjs % add all y-* modules you want to use
+```
+
+If you don't include via script tag, you have to explicitly include all modules!
+(Same goes for other module systems)
+```
+var Y = require('yjs')
+require('y-array')(Y) // add the y-array type to Yjs
+require('y-websockets-client')(Y)
+require('y-memory')(Y)
+require('y-map')(Y)
+require('y-text')(Y)
+// ..
+// do the same for all modules you want to use
+```
+
+### ES6 Syntax
+
+```
+import Y from 'yjs'
+import yArray from 'y-array'
+import yWebsocketsClient from 'y-webrtc'
+import yMemory from 'y-memory'
+import yMap from 'y-map'
+import yText from 'y-text'
+// ..
+Y.extend(yArray, yWebsocketsClient, yMemory, yArray, yMap, yText /*, .. */)
+```
+
+# Text editing example
+
+Install dependencies
+```
+bower i yjs y-memory y-webrtc y-array y-text
+```
+
+Here is a simple example of a shared textarea
+```HTML
+  <!DOCTYPE html>
+  <html>
+    <body>
+      <script src="./bower_components/yjs/y.js"></script>
+      <!-- Yjs automatically includes all missing dependencies (browser only) -->
+      <script>
+        Y({
+          db: {
+            name: 'memory' // use memory database adapter.
+            // name: 'indexeddb' // use indexeddb database adapter instead for offline apps
+          },
+          connector: {
+            name: 'webrtc', // use webrtc connector
+            // name: 'websockets-client'
+            // name: 'xmpp'
+            room: 'my-room' // clients connecting to the same room share data
+          },
+          sourceDir: './bower_components', // location of the y-* modules (browser only)
+          share: {
+            textarea: 'Text' // y.share.textarea is of type y-text
+          }
+        }).then(function (y) {
+          // The Yjs instance `y` is available
+          // y.share.* contains the shared types
+
+          // Bind `y.share.textarea` to `<textarea/>`
+          y.share.textarea.bind(document.querySelector('textarea'))
+        })
+      </script>
+      <textarea></textarea>
+    </body>
+  </html>
+```
+
+## Get Help & Give Help
+There are some friendly people on [![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/y-js/yjs?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge) who are eager to help, and answer questions. Please join!
+
+Report _any_ issues to the
+[Github issue page](https://github.com/y-js/yjs/issues)! I try to fix them very
+soon, if possible.
+
+# API
+
+### Y(options)
+* Y.extend(module1, module2, ..)
+  * Add extensions to Y
+  * `Y.extend(require('y-webrtc'))` has the same semantics as
+    `require('y-webrtc')(Y)`
+* options.db
+  * Will be forwarded to the database adapter. Specify the database adaper on
+    `options.db.name`.
+  * Have a look at the used database adapter repository to see all available
+    options.
+* options.connector
+  * Will be forwarded to the connector adapter. Specify the connector adaper on
+    `options.connector.name`.
+  * All our connectors implement a `room` property. Clients that specify the
+    same room share the same data.
+  * All of our connectors specify an `url` property that defines the connection
+    endpoint of the used connector.
+    * All of our connectors also have a default connection endpoint that you can
+      use for development.
+  * Set `options.connector.generateUserId = true` in order to genenerate a
+    userid, instead of receiving one from the server. This way the `Y(..)` is
+    immediately going to be resolved, without waiting for any confirmation from
+    the server. Use with caution.
+  * Have a look at the used connector repository to see all available options.
+  * *Only if you know what you are doing:* Set
+    `options.connector.preferUntransformed = true` in order receive the shared
+    data untransformed. This is very efficient as the database content is simply
+    copied to this client. This does only work if this client receives content
+    from only one client.
+* options.sourceDir (browser only)
+  * Path where all y-* modules are stored
+  * Defaults to `/bower_components`
+  * Not required when running on `nodejs` / `iojs`
+  * When using nodejs you need to manually extend Yjs:
+```
+var Y = require('yjs')
+// you have to require a db, connector, and *all* types you use!
+require('y-memory')(Y)
+require('y-webrtc')(Y)
+require('y-map')(Y)
+// ..
+```
+* options.share
+  * Specify on `options.share[arbitraryName]` types that are shared among all
+    users.
+  * E.g. Specify `options.share[arbitraryName] = 'Array'` to require y-array and
+    create an y-array type on `y.share[arbitraryName]`.
+  * If userA doesn't specify `options.share[arbitraryName]`, it won't be
+    available for userA.
+  * If userB specifies `options.share[arbitraryName]`, it still won't be
+    available for userA. But all the updates are send from userB to userA.
+  * In contrast to y-map, types on `y.share.*` cannot be overwritten or deleted.
+    Instead, they are merged among all users. This feature is only available on
+    `y.share.*`
+  * Weird behavior: It is supported that two users specify different types with
+    the same property name.
+     E.g. userA specifies `options.share.x = 'Array'`, and userB specifies
+     `options.share.x = 'Text'`. But they only share data if they specified the
+     same type with the same property name
+* options.type (browser only)
+  * Array of modules that Yjs needs to require, before instantiating a shared
+    type.
+  * By default Yjs requires the specified database adapter, the specified
+    connector, and all modules that are used in `options.share.*`
+  * Put all types here that you intend to use, but are not used in y.share.*
+
+### Instantiated Y object (y)
+`Y(options)` returns a promise that is fulfilled when..
+
+* All modules are loaded
+  * The specified database adapter is loaded
+  * The specified connector is loaded
+  * All types are included
+* The connector is initialized, and a unique user id is set (received from the
+  server)
+  * Note: When using y-indexeddb, a retrieved user id is stored on `localStorage`
+
+The promise returns an instance of Y. We denote it with a lower case `y`.
+
+* y.share.*
+  * Instances of the types you specified on options.share.*
+  * y.share.* can only be defined once when you instantiate Y!
+* y.connector is an instance of Y.AbstractConnector
+* y.connector.onUserEvent(function (event) {..})
+  * Observe user events (event.action is either 'userLeft' or 'userJoined')
+* y.connector.whenSynced(listener)
+  * `listener` is executed when y synced with at least one user.
+  * `listener` is not called when no other user is in the same room.
+  * y-websockets-client aways waits to sync with the server
+* y.connector.disconnect()
+  * Force to disconnect this instance from the other instances
+* y.connector.connect()
+  * Try to reconnect to the other instances (needs to be supported by the
+    connector)
+  * Not supported by y-xmpp
+* y.close()
+  * Destroy this object.
+  * Destroys all types (they will throw weird errors if you still use them)
+  * Disconnects from the other instances (via connector)
+  * Returns a promise
+* y.destroy()
+  * calls y.close()
+  * Removes all data from the database
+  * Returns a promise
+* y.db.stopGarbageCollector()
+  * Stop the garbage collector. Call y.db.garbageCollect() to continue garbage
+    collection
+* y.db.gc :: Boolean
+  * Whether gc is turned on
+* y.db.gcTimeout :: Number (defaults to 50000 ms)
+  * Time interval between two garbage collect cycles
+  * It is required that all instances exchanged all messages after two garbage
+    collect cycles (after 100000 ms per default)
+* y.db.userId :: String
+  * The used user id for this client. **Never overwrite this**
+
+### Logging
+Yjs uses [debug](https://github.com/visionmedia/debug) for logging. The flag
+`y*` enables logging for all y-* components. You can selectively remove
+components you are not interested in: E.g. The flag `y*,-y:connector-message`
+will not log the long `y:connector-message` messages.
+
+##### Enable logging in Node.js
+```sh
+DEBUG=y* node app.js
+```
+
+Remove the colors in order to log to a file:
+```sh
+DEBUG_COLORS=0 DEBUG=y* node app.js > log
+```
+
+##### Enable logging in the browser
+```js
+localStorage.debug = 'y*'
+```
+
+## License
+Yjs is licensed under the [MIT License](./LICENSE).
--- a/README.v13.md
+++ b/README.v13.md
@@ -1,869 +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](#YDoc)
-  * [Document Updates](#Document-Updates)
-  * [Relative Positions](#Relative-Positions)
-  * [Y.UndoManager](#YUndoManager)
-* [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/) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; | ✔ | [y-prosemirror](http://github.com/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('ws://localhost:1234', 'roomname', 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
-```
-
-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>forEach(function(index:number,value:object|boolean|Array|string|number|Uint8Array|Y.Type))</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|Uint8Array&gt;</code></b>
-    <dd>
-Copies the <code>[key,value]</code> pairs of this YMap to a new Object.It
-transforms all child types to JSON using their <code>toJSON</code> method.
-    </dd>
-    <b><code>forEach(function(key:string,value:object|boolean|Array|string|number|Uint8Array|Y.Type))</code></b>
-    <dd>
-      Execute the provided function once for every key-value pair.
-    </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>
-
-### Y.UndoManager
-
-Yjs ships with an Undo/Redo manager for selective undo/redo of of changes on a
-Yjs type. The changes can be optionally scoped to transaction origins.
-
-```js
-const ytext = doc.getArray('array')
-const undoManager = new Y.UndoManager(ytext)
-
-ytext.insert(0, 'abc')
-undoManager.undo()
-ytext.toString() // => ''
-undoManager.redo()
-ytext.toString() // => 'abc'
-```
-
-<dl>
-  <b><code>constructor(scope:Y.AbstractType|Array&lt;Y.AbstractType&gt;,
-  [[{captureTimeout:number,trackedOrigins:Set&lt;any&gt;,deleteFilter:function(item):boolean}]])</code></b>
-  <dd>Accepts either single type as scope or an array of types.</dd>
-  <b><code>undo()</code></b>
-  <dd></dd>
-  <b><code>redo()</code></b>
-  <dd></dd>
-  <b><code>stopCapturing()</code></b>
-  <dd></dd>
-  <b>
-    <code>
-on('stack-item-added', { stackItem: { meta: Map&lt;any,any&gt; }, type: 'undo'
-| 'redo' })
-    </code>
-  </b>
-  <dd>
-Register an event that is called when a <code>StackItem</code> is added to the
-undo- or the redo-stack.
-  </dd>
-  <b>
-    <code>
-on('stack-item-popped', { stackItem: { meta: Map&lt;any,any&gt; }, type: 'undo'
-| 'redo' })
-    </code>  
-  </b>
-  <dd>
-Register an event that is called when a <code>StackItem</code> is popped from
-the undo- or the redo-stack.
-  </dd>
-</dl>
-
-#### Example: Stop Capturing
-
-UndoManager merges Undo-StackItems if they are created within time-gap
-smaller than `options.captureTimeout`. Call `um.stopCapturing()` so that the next
-StackItem won't be merged.
-
-```js
-// 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)
-```
-
-#### Example: Specify tracked origins
-
-Every change on the shared document has an origin. If no origin was specified,
-it defaults to `null`. By specifying `trackedTransactionOrigins` you can
-selectively specify which changes should be tracked by `UndoManager`. The
-UndoManager instance is always added to `trackedTransactionOrigins`.
-
-```js
-class CustomBinding {}
-
-const ytext = doc.getArray('array')
-const undoManager = new Y.UndoManager(ytext, new Set([42, CustomBinding]))
-
-ytext.insert(0, 'abc')
-undoManager.undo()
-ytext.toString() // => 'abc' (does not track because origin `null` and not part
-                 //           of `trackedTransactionOrigins`)
-ytext.delete(0, 3) // revert change
-
-doc.transact(() => {
-  ytext.insert(0, 'abc')
-}, 42)
-undoManager.undo()
-ytext.toString() // => '' (tracked because origin is an instance of `trackedTransactionorigins`)
-
-doc.transact(() => {
-  ytext.insert(0, 'abc')
-}, 41)
-undoManager.undo()
-ytext.toString() // => '' (not tracked because 41 is not an instance of
-                 //        `trackedTransactionorigins`)
-ytext.delete(0, 3) // revert change
-
-doc.transact(() => {
-  ytext.insert(0, 'abc')
-}, new CustomBinding())
-undoManager.undo()
-ytext.toString() // => '' (tracked because origin is a `CustomBinding` and
-                 //        `CustomBinding` is in `trackedTransactionorigins`)
-```
-
-#### Example: Add additional information to the StackItems
-
-When undoing or redoing a previous action, it is often expected to restore
-additional meta information like the cursor location or the view on the
-document. You can assign meta-information to Undo-/Redo-StackItems.
-
-```js
-const ytext = doc.getArray('array')
-const undoManager = new Y.UndoManager(ytext, new Set([42, CustomBinding]))
-
-undoManager.on('stack-item-added', event => {
-  // save the current cursor location on the stack-item
-  event.stackItem.meta.set('cursor-location', getRelativeCursorLocation())
-})
-
-undoManager.on('stack-item-popped', event => {
-  // restore the current cursor location on the stack-item
-  restoreCursorLocation(event.stackItem.meta.get('cursor-location'))
-})
-```
-
-## 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.
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
  "name": "yjs",
-  "version": "13.0.0-96",
+  "version": "13.0.0-97",
  "lockfileVersion": 1,
  "requires": true,
  "dependencies": {
@@ -42,9 +42,9 @@
      }
    },
    "acorn": {
-      "version": "6.1.1",
-      "resolved": "https://registry.npmjs.org/acorn/-/acorn-6.1.1.tgz",
-      "integrity": "sha512-jPTiwtOxaHNaAPg/dmrJ/beuzLRnXtB0kQPQ8JpotKJgTB6rX6c8mlf315941pyjBSaPg8NHXS9fhP4u17DpGA==",
+      "version": "7.0.0",
+      "resolved": "https://registry.npmjs.org/acorn/-/acorn-7.0.0.tgz",
+      "integrity": "sha512-PaF/MduxijYYt7unVGRuds1vBC9bFxbNf+VWqhOClfdgy7RlVkQqt610ig1/yxTgsDIfW1cWDel5EBbOy3jdtQ==",
      "dev": true
    },
    "acorn-jsx": {
@@ -2596,9 +2596,9 @@
      }
    },
    "lib0": {
-      "version": "0.0.6",
-      "resolved": "https://registry.npmjs.org/lib0/-/lib0-0.0.6.tgz",
-      "integrity": "sha512-drb8LcwZu2rAmTsXN0d3hFtZVbPE5ZUrsWf307Boc/v7IrmLq3lM5+OOMY672EysHTWeXo/OH54wRHyD6eFXXw=="
+      "version": "0.1.0",
+      "resolved": "https://registry.npmjs.org/lib0/-/lib0-0.1.0.tgz",
+      "integrity": "sha512-pkpnv2IJEOb6iwpcJ6BVQu9GkZ9VINKeQ/0BcArHpozqaGQYWe+ychf2p9wHKToHUnivPoGZZ7rFqrxNXjqFBg=="
    },
    "linkify-it": {
      "version": "2.2.0",
@@ -3492,14 +3492,22 @@
      }
    },
    "rollup": {
-      "version": "1.12.4",
-      "resolved": "https://registry.npmjs.org/rollup/-/rollup-1.12.4.tgz",
-      "integrity": "sha512-sHg0F05oTMJzM592MWU8irsPx8LIFMKSCnEkcp6vp/gnj+oJ9GJEBW9hl8jUqy2L6Q2uUxFzPgvoExLbfuSODA==",
+      "version": "1.20.3",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-1.20.3.tgz",
+      "integrity": "sha512-/OMCkY0c6E8tleeVm4vQVDz24CkVgvueK3r8zTYu2AQNpjrcaPwO9hE+pWj5LTFrvvkaxt4MYIp2zha4y0lRvg==",
      "dev": true,
      "requires": {
        "@types/estree": "0.0.39",
-        "@types/node": "^12.0.2",
-        "acorn": "^6.1.1"
+        "@types/node": "^12.7.2",
+        "acorn": "^7.0.0"
+      },
+      "dependencies": {
+        "@types/node": {
+          "version": "12.7.4",
+          "resolved": "https://registry.npmjs.org/@types/node/-/node-12.7.4.tgz",
+          "integrity": "sha512-W0+n1Y+gK/8G2P/piTkBBN38Qc5Q1ZSO6B5H3QmPCUewaiXOo2GCAWZ4ElZCcNhjJuBSUSLGFUJnmlCn5+nxOQ==",
+          "dev": true
+        }
      }
    },
    "rollup-cli": {
@@ -4158,9 +4166,9 @@
      "dev": true
    },
    "typescript": {
-      "version": "3.4.5",
-      "resolved": "https://registry.npmjs.org/typescript/-/typescript-3.4.5.tgz",
-      "integrity": "sha512-YycBxUb49UUhdNMU5aJ7z5Ej2XGmaIBL0x34vZ82fn3hGvD+bgrMrVDpatgz2f7YxUMJxMkbWxJZeAvDxVe7Vw==",
+      "version": "3.6.2",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-3.6.2.tgz",
+      "integrity": "sha512-lmQ4L+J6mnu3xweP8+rOrUwzmN+MRAj7TgtJtDaXE5PMyX2kCrklhg3rvOsOIfNeAWMQWO2F1GPc1kMD2vLAfw==",
      "dev": true
    },
    "uc.micro": {
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
  "name": "yjs",
-  "version": "13.0.0-96",
+  "version": "13.0.0-97",
  "description": "Shared Editing Library",
  "main": "./dist/yjs.js",
  "module": "./dist/yjs.mjs",
@@ -10,8 +10,8 @@
    "test-exhaustive": "npm run lint && npm run dist && node ./dist/tests.js --repitition-time 10000",
    "dist": "rm -rf dist && rollup -c",
    "watch": "rollup -wc",
-    "lint": "markdownlint README.v13.md && standard && tsc",
-    "docs": "rm -rf docs; jsdoc --configure ./.jsdoc.json --verbose --readme ./README.v13.md --package ./package.json || true",
+    "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 && serve ./docs/",
    "preversion": "npm run lint && PRODUCTION=1 npm run dist && npm run docs && node ./dist/tests.js --repitition-time 1000",
    "postversion": "git push && git push --tags",
@@ -38,31 +38,31 @@
  },
  "repository": {
    "type": "git",
-    "url": "https://github.com/y-js/yjs.git"
+    "url": "https://github.com/yjs/yjs.git"
  },
  "keywords": [
    "crdt"
  ],
  "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": "0.0.6"
+    "lib0": "^0.1.0"
  },
  "devDependencies": {
    "concurrently": "^3.6.1",
    "jsdoc": "^3.6.3",
    "live-server": "^1.2.1",
-    "rollup": "^1.11.3",
+    "rollup": "^1.20.3",
    "rollup-cli": "^1.0.9",
    "rollup-plugin-node-resolve": "^4.2.4",
    "standard": "^11.0.1",
    "tui-jsdoc-template": "^1.2.2",
-    "typescript": "^3.4.5",
+    "typescript": "^3.6.2",
    "y-protocols": "0.0.6"
  }
 }
--- a/src/index.js
+++ b/src/index.js
@@ -37,6 +37,9 @@ export {
  compareIDs,
  getState,
  Snapshot,
+  createSnapshot,
+  snapshot,
+  emptySnapshot,
  findRootTypeKey,
  typeListToArraySnapshot,
  typeMapGetSnapshot,
@@ -44,5 +47,9 @@ export {
  applyUpdate,
  encodeStateAsUpdate,
  encodeStateVector,
-  UndoManager
+  UndoManager,
+  decodeSnapshot,
+  encodeSnapshot,
+  isDeleted,
+  equalSnapshots
 } from './internals.js'
--- a/src/types/AbstractType.js
+++ b/src/types/AbstractType.js
@@ -584,7 +584,7 @@ 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.content.getContent()[v.length - 1] : undefined
--- a/src/types/YText.js
+++ b/src/types/YText.js
@@ -16,11 +16,20 @@ import {
  ContentEmbed,
  ContentFormat,
  ContentString,
+  splitSnapshotAffectedStructs,
  Doc, Item, Snapshot, StructStore, 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 {
  /**
@@ -130,7 +139,7 @@ const insertNegatedAttributes = (transaction, parent, left, right, negatedAttrib
    right !== null && (
      right.deleted === true || (
        right.content.constructor === ContentFormat &&
-        (negatedAttributes.get(/** @type {ContentFormat} */ (right.content).key) === /** @type {ContentFormat} */ (right.content).value)
+        equalAttrs(negatedAttributes.get(/** @type {ContentFormat} */ (right.content).key), /** @type {ContentFormat} */ (right.content).value)
      )
    )
  ) {
@@ -180,7 +189,7 @@ const minimizeAttributeChanges = (left, right, currentAttributes, attributes) =>
      break
    } else if (right.deleted) {
      // continue
-    } else if (right.content.constructor === ContentFormat && (attributes[(/** @type {ContentFormat} */ (right.content)).key] || null) === /** @type {ContentFormat} */ (right.content).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
      updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (right.content))
    } else {
@@ -210,7 +219,7 @@ const insertAttributes = (transaction, parent, left, right, currentAttributes, a
  for (let 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 Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentFormat(key, val))
@@ -272,13 +281,13 @@ 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) {
+    if (!right.deleted) {
      switch (right.content.constructor) {
        case ContentFormat:
          const { key, value } = /** @type {ContentFormat} */ (right.content)
          const attr = attributes[key]
          if (attr !== undefined) {
-            if (attr === value) {
+            if (equalAttrs(attr, value)) {
              negatedAttributes.delete(key)
            } else {
              negatedAttributes.set(key, value)
@@ -516,11 +525,11 @@ export class YTextEvent extends YEvent {
              if (this.adds(item)) {
                if (!this.deletes(item)) {
                  const curVal = currentAttributes.get(key) || null
-                  if (curVal !== value) {
+                  if (!equalAttrs(curVal, value)) {
                    if (action === 'retain') {
                      addOp()
                    }
-                    if (value === (oldAttributes.get(key) || null)) {
+                    if (equalAttrs(value, (oldAttributes.get(key) || null))) {
                      delete attributes[key]
                    } else {
                      attributes[key] = value
@@ -532,7 +541,7 @@ export class YTextEvent extends YEvent {
              } else if (this.deletes(item)) {
                oldAttributes.set(key, value)
                const curVal = currentAttributes.get(key) || null
-                if (curVal !== value) {
+                if (!equalAttrs(curVal, value)) {
                  if (action === 'retain') {
                    addOp()
                  }
@@ -542,7 +551,7 @@ export class YTextEvent extends YEvent {
                oldAttributes.set(key, value)
                const attr = attributes[key]
                if (attr !== undefined) {
-                  if (attr !== value) {
+                  if (!equalAttrs(attr, value)) {
                    if (action === 'retain') {
                      addOp()
                    }
@@ -715,6 +724,7 @@ export class YText extends AbstractType {
     */
    const ops = []
    const currentAttributes = new Map()
+    const doc = /** @type {Doc} */ (this.doc)
    let str = ''
    let n = this._start
    function packStr () {
@@ -740,42 +750,54 @@ export class YText extends AbstractType {
        str = ''
      }
    }
-    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', { 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')
-            }
-            str += /** @type {ContentString} */ (n.content).str
-            break
-          case ContentEmbed:
-            packStr()
-            ops.push({
-              insert: /** @type {ContentEmbed} */ (n.content).embed
-            })
-            break
-          case ContentFormat:
-            packStr()
-            updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (n.content))
-            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', { 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')
+              }
+              str += /** @type {ContentString} */ (n.content).str
+              break
+            case ContentEmbed:
+              packStr()
+              ops.push({
+                insert: /** @type {ContentEmbed} */ (n.content).embed
+              })
+              break
+            case ContentFormat:
+              if (isVisible(n, snapshot)) {
+                packStr()
+                updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (n.content))
+              }
+              break
+          }
+        }
+        n = n.right
+      }
+      packStr()
+    }, splitSnapshotAffectedStructs)
    return ops
  }

@@ -784,12 +806,12 @@ 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
    }
@@ -797,6 +819,10 @@ export class YText extends AbstractType {
    if (y !== null) {
      transact(y, transaction => {
        const { left, right, currentAttributes } = findPosition(transaction, y.store, this, index)
+        if (!attributes) {
+          attributes = {}
+          currentAttributes.forEach((v, k) => { attributes[k] = v })
+        }
        insertText(transaction, this, left, right, currentAttributes, text, attributes)
      })
    } else {
--- a/src/types/YXmlFragment.js
+++ b/src/types/YXmlFragment.js
@@ -151,6 +151,10 @@ export class YXmlFragment extends AbstractType {
    return new YXmlFragment()
  }

+  get length () {
+    return this._prelimContent === null ? this._length : this._prelimContent.length
+  }
+
  /**
   * Create a subtree of childNodes.
   *
--- a/src/utils/DeleteSet.js
+++ b/src/utils/DeleteSet.js
@@ -169,6 +169,8 @@ 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
@@ -177,7 +179,7 @@ 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>}
@@ -224,6 +226,26 @@ 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
@@ -232,7 +254,7 @@ 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++) {
@@ -279,6 +301,7 @@ 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)))
--- a/src/utils/Snapshot.js
+++ b/src/utils/Snapshot.js
@@ -1,15 +1,31 @@

 import {
  isDeleted,
-  DeleteSet, Item // 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
@@ -20,16 +36,79 @@ export class Snapshot {
     * @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 {Doc} doc
+ * @return {Snapshot}
+ */
+export const snapshot = doc => createSnapshot(createDeleteSetFromStructStore(doc.store), getStateVector(doc.store))
+
 /**
 * @param {Item} item
 * @param {Snapshot|undefined} snapshot
@@ -38,5 +117,24 @@ export const createSnapshot = (ds, sm) => new Snapshot(ds, sm)
 * @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, store, createID(client, clock))
+      }
+    })
+    iterateDeletedStructs(transaction, snapshot.ds, store, item => {})
+    meta.add(snapshot)
+  }
+}
--- a/src/utils/Transaction.js
+++ b/src/utils/Transaction.js
@@ -90,6 +90,11 @@ export class Transaction {
     * @type {any}
     */
    this.origin = origin
+    /**
+     * Stores meta information on the transaction
+     * @type {Map<any,any>}
+     */
+    this.meta = new Map()
  }
 }

--- a/src/utils/YEvent.js
+++ b/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
  }

  /**
@@ -65,6 +72,113 @@ export class YEvent {
  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)) {
+              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 changes
+  }
 }

 /**
--- a/src/utils/encoding.js
+++ b/src/utils/encoding.js
@@ -23,7 +23,7 @@ import {
  readID,
  getState,
  getStateVector,
-  readDeleteSet,
+  readAndApplyDeleteSet,
  writeDeleteSet,
  createDeleteSetFromStructStore,
  Doc, Transaction, AbstractStruct, StructStore, ID // eslint-disable-line
@@ -230,7 +230,7 @@ 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)
  }
 }

@@ -301,7 +301,7 @@ export const readStructs = (decoder, transaction, store) => {
 export const readUpdate = (decoder, ydoc, transactionOrigin) =>
  ydoc.transact(transaction => {
    readStructs(decoder, transaction, ydoc.store)
-    readDeleteSet(decoder, transaction, ydoc.store)
+    readAndApplyDeleteSet(decoder, transaction, ydoc.store)
  }, transactionOrigin)

 /**
@@ -381,6 +381,22 @@ 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`.
 *
@@ -389,16 +405,7 @@ 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.
--- a/tests/testHelper.js
+++ b/tests/testHelper.js
@@ -378,7 +378,7 @@ 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) {
--- a/tests/y-array.tests.js
+++ b/tests/y-array.tests.js
@@ -191,6 +191,33 @@ 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
 */
@@ -211,7 +238,7 @@ export const testInsertAndDeleteEventsForTypes2 = tc => {
 }

 /**
- * This issue has been reported here https://github.com/y-js/yjs/issues/155
+ * This issue has been reported here https://github.com/yjs/yjs/issues/155
 * @param {t.TestCase} tc
 */
 export const testNewChildDoesNotEmitEventInTransaction = tc => {
--- a/tests/y-map.tests.js
+++ b/tests/y-map.tests.js
@@ -292,6 +292,54 @@ 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
 */
--- a/tests/y-text.tests.js
+++ b/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
@@ -87,3 +87,65 @@ export const testGetDeltaWithEmbeds = tc => {
    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: { state: 'added' }}}, {insert: 'b', attributes: {ychange: { state: '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' }])
+}
Author	SHA1	Message	Date
Kevin Jahns	d9fface0be	13.0.0-97	2019-09-04 13:21:10 +02:00
Kevin Jahns	7d5db917da	fix type error >= tsc@3.6	2019-09-04 13:19:25 +02:00
Kevin Jahns	6e7529723d	update lib0	2019-09-04 13:15:34 +02:00
Kevin Jahns	6cb64b3707	move repository to yjs org	2019-09-04 13:08:34 +02:00
Kevin Jahns	bb1c0b809f	implement snapshot & event.changes	2019-09-03 16:33:29 +02:00
Kevin Jahns	8bcff6138c	Y.Text snapshot support (toDelta)	2019-08-31 22:42:18 +02:00
Kevin Jahns	e78d84ee59	md lint	2019-08-31 16:47:12 +02:00
Kevin Jahns	c23bcb66ce	delta format: use flat attr comparison	2019-08-31 16:44:07 +02:00
Kevin Jahns	5fddcef3ea	Update logo	2019-08-29 12:51:16 +02:00
Kevin Jahns	e1e46c6eb1	Merge branch 'master' of github.com:y-js/yjs	2019-08-27 02:17:16 +02:00
Kevin Jahns	13ad0c8464	implement Y.XmlFragment.length	2019-08-27 02:17:08 +02:00
Kevin Jahns	7700b50470	Merge pull request #161 from blackening/master Updated documentation for Y.Array forEach	2019-08-20 23:18:46 +02:00
blackening	f0262ffaae	Updated documentation for Y.Array forEach Reference: https://github.com/y-js/yjs/blob/master/src/types/YArray.js#L186 https://github.com/y-js/yjs/blob/master/src/types/AbstractType.js#L239	2019-07-09 19:58:06 +08:00