13.4.10

Update README.md

.circleci/config.yml

@@ -0,0 +1,7 @@
+version: 2.1
+orbs:
+  node: circleci/node@3.0.0
+workflows:
+  node-tests:
+    jobs:
+      - node/test

.github/workflows/node.js.yml

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

INTERNALS.md

@@ -12,7 +12,7 @@ which aren't described in the paper. The most notable is that items have an
 `originRight` as well as an `origin` property, which improves performance when
 many concurrent inserts happen after the same character.
 
-At it heart, Yjs is a list CRDT. Everything is squeezed into a list in order to
+At its heart, Yjs is a list CRDT. Everything is squeezed into a list in order to
 reuse the CRDT resolution algorithm:
 
 - Arrays are easy - they're lists of arbitrary items.

README.md

@@ -31,29 +31,30 @@ I'm currently looking for sponsors that allow me to be less dependent on
 contracting work. These awesome backers already fund further development of
 Yjs:
 
-[![Vincent Waller](https://github.com/vwall.png?size=60)](https://github.com/vwall)
-[<img src="https://user-images.githubusercontent.com/5553757/83337333-a7bcb380-a2ba-11ea-837b-e404eb35d318.png"
-height="60px" />](https://input.com/)
-[![Duane Johnson](https://github.com/canadaduane.png?size=60)](https://github.com/canadaduane)
-[![Joe Reeve](https://github.com/ISNIT0.png?size=60)](https://github.com/ISNIT0)
-[<img src="https://room.sh/img/icons/android-chrome-192x192.png" height="60px" />](https://room.sh/)
+[![davidhq](https://github.com/davidhq.png?size=60)](https://github.com/davidhq)
+[![Ifiok Jr.](https://github.com/ifiokjr.png?size=60)](https://github.com/ifiokjr)
+[![Burke Libbey](https://github.com/burke.png?size=60)](https://github.com/burke)
+[![Beni Cherniavsky-Paskin](https://github.com/cben.png?size=60)](https://github.com/cben)
+[![Tom Moor](https://github.com/tommoor.png?size=60)](https://github.com/tommoor)
+[![Michael Meyers](https://github.com/michaelemeyers.png?size=60)](https://github.com/michaelemeyers)
+[![Cristiano Benjamin](https://github.com/csbenjamin.png?size=60)](https://github.com/csbenjamin)
+[![Braden](https://github.com/AdventureBeard.png?size=60)](https://github.com/AdventureBeard)
+[![nimbuswebinc](https://nimbusweb.me/new-style-img/note-icon.svg)](https://github.com/nimbuswebinc)
 [![JourneyApps](https://github.com/journeyapps.png?size=60)](https://github.com/journeyapps)
 [![Adam Brunnmeier](https://github.com/adabru.png?size=60)](https://github.com/adabru)
 [![Nathanael Anderson](https://github.com/NathanaelA.png?size=60)](https://github.com/NathanaelA)
-[![Gremloon](https://github.com/gremloon.png?size=60)](https://github.com/gremloon)
-[![ifiokjr](https://github.com/ifiokjr.png?size=60)](https://github.com/ifiokjr)
-[![mrfambo](https://github.com/mrfambo.png?size=60)](https://github.com/mrfambo)
+[<img src="https://room.sh/img/icons/android-chrome-192x192.png" height="60px" />](https://room.sh/)
 
 Sponsorship also comes with special perks! [![Become a Sponsor](https://img.shields.io/static/v1?label=Become%20a%20Sponsor&message=%E2%9D%A4&logo=GitHub&style=flat&color=d42f2d)](https://github.com/sponsors/dmonad)
 
 ## Who is using Yjs
 
-* [Relm](http://www.relm.us/) A collaborative gameworld for teamwork and
+* [Relm](https://www.relm.us/) A collaborative gameworld for teamwork and
   community. :star2:
 * [Input](https://input.com/) A collaborative note taking app. :star2:
 * [Room.sh](https://room.sh/) A meeting application with integrated
   collaborative drawing, editing, and coding tools. :star:
-* [http://coronavirustechhandbook.com/](https://coronavirustechhandbook.com/)
+* [https://coronavirustechhandbook.com/](https://coronavirustechhandbook.com/)
   A collaborative wiki that is edited by thousands of different people to work
   on a rapid and sophisticated response to the coronavirus outbreak and
   subsequent impacts. :star:
@@ -64,6 +65,8 @@ Sponsorship also comes with special perks! [![Become a Sponsor](https://img.shie
   collaboratively organize radio broadcasts.
 * [Cattaz](http://cattaz.io/) A wiki that can run custom applications in the
   wiki pages.
+* [Alldone](https://alldoneapp.com/) A next-gen project management and
+  collaboration platform.
 
 ## Table of Contents
 
@@ -90,10 +93,10 @@ are implemented in separate modules.
 
 | Name | Cursors | Binding |  Demo |
 |---|:-:|---|---|
-| [ProseMirror](https://prosemirror.net/) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; | ✔ | [y-prosemirror](http://github.com/yjs/y-prosemirror) | [demo](https://demos.yjs.dev/prosemirror/prosemirror.html) |
-| [Quill](https://quilljs.com/) | ✔ | [y-quill](http://github.com/yjs/y-quill) | [demo](https://demos.yjs.dev/quill/quill.html) |
-| [CodeMirror](https://codemirror.net/) | ✔ | [y-codemirror](http://github.com/yjs/y-codemirror) | [demo](https://demos.yjs.dev/codemirror/codemirror.html) |
-| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](http://github.com/yjs/y-monaco) | [demo](https://demos.yjs.dev/monaco/monaco.html) |
+| [ProseMirror](https://prosemirror.net/) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; | ✔ | [y-prosemirror](https://github.com/yjs/y-prosemirror) | [demo](https://demos.yjs.dev/prosemirror/prosemirror.html) |
+| [Quill](https://quilljs.com/) | ✔ | [y-quill](https://github.com/yjs/y-quill) | [demo](https://demos.yjs.dev/quill/quill.html) |
+| [CodeMirror](https://codemirror.net/) | ✔ | [y-codemirror](https://github.com/yjs/y-codemirror) | [demo](https://demos.yjs.dev/codemirror/codemirror.html) |
+| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](https://github.com/yjs/y-monaco) | [demo](https://demos.yjs.dev/monaco/monaco.html) |
 
 ### Providers
 
@@ -103,7 +106,7 @@ manage all that for you and are the perfect starting point for your
 collaborative app.
 
 <dl>
-  <dt><a href="http://github.com/yjs/y-webrtc">y-webrtc</a></dt>
+  <dt><a href="https://github.com/yjs/y-webrtc">y-webrtc</a></dt>
   <dd>
 Propagates document updates peer-to-peer using WebRTC. The peers exchange
 signaling data over signaling servers. Publically available signaling servers
@@ -111,19 +114,19 @@ are available. Communication over the signaling servers can be encrypted by
 providing a shared secret, keeping the connection information and the shared
 document private.
   </dd>
-  <dt><a href="http://github.com/yjs/y-websocket">y-websocket</a></dt>
+  <dt><a href="https://github.com/yjs/y-websocket">y-websocket</a></dt>
   <dd>
 A module that contains a simple websocket backend and a websocket client that
 connects to that backend. The backend can be extended to persist updates in a
 leveldb database.
   </dd>
-  <dt><a href="http://github.com/yjs/y-indexeddb">y-indexeddb</a></dt>
+  <dt><a href="https://github.com/yjs/y-indexeddb">y-indexeddb</a></dt>
   <dd>
 Efficiently persists document updates to the browsers indexeddb database.
 The document is immediately available and only diffs need to be synced through the
 network provider.
   </dd>
-  <dt><a href="http://github.com/yjs/y-dat">y-dat</a></dt>
+  <dt><a href="https://github.com/yjs/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
@@ -198,7 +201,7 @@ const ydoc = new Y.Doc()
 
 // this allows you to instantly get the (cached) documents data
 const indexeddbProvider = new IndexeddbPersistence('count-demo', ydoc)
-idbP.whenSynced.then(() => {
+indexeddbProvider.whenSynced.then(() => {
   console.log('loaded data from indexed db')
 })
 
@@ -241,6 +244,8 @@ necessary.
   </p>
   <pre>const yarray = new Y.Array()</pre>
   <dl>
+    <b><code>parent:Y.AbstractType|null</code></b>
+    <dd></dd>
     <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.
@@ -255,6 +260,8 @@ position 0.
     <dd></dd>
     <b><code>get(index:number)</code></b>
     <dd></dd>
+    <b><code>slice(start:number, end:number):Array&lt;Object|boolean|Array|string|number|Uint8Array|Y.Type&gt;</code></b>
+    <dd>Retrieve a range of content</dd>
     <b><code>length:number</code></b>
     <dd></dd>
     <b>
@@ -310,6 +317,8 @@ or any of its children.
   </p>
   <pre><code>const ymap = new Y.Map()</code></pre>
   <dl>
+    <b><code>parent:Y.AbstractType|null</code></b>
+    <dd></dd>
     <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>
@@ -320,6 +329,8 @@ or any of its children.
     <dd></dd>
     <b><code>get(index:number)</code></b>
     <dd></dd>
+    <b><code>clone():Y.Map</code></b>
+    <dd>Clone this type into a fresh Yjs type.</dd>
     <b><code>toJSON():Object&lt;string, Object|boolean|Array|string|number|Uint8Array&gt;</code></b>
     <dd>
 Copies the <code>[key,value]</code> pairs of this YMap to a new Object.It
@@ -387,6 +398,8 @@ YTextEvents compute changes as deltas.
   </p>
   <pre>const ytext = new Y.Text()</pre>
   <dl>
+    <b><code>parent:Y.AbstractType|null</code></b>
+    <dd></dd>
     <b><code>insert(index:number, content:string, [formattingAttributes:Object&lt;string,string&gt;])</code></b>
     <dd>
       Insert a string at <var>index</var> and assign formatting attributes to it.
@@ -445,14 +458,22 @@ or any of its children.
   </p>
   <pre><code>const yxml = new Y.XmlFragment()</code></pre>
   <dl>
+    <b><code>parent:Y.AbstractType|null</code></b>
+    <dd></dd>
+    <b><code>firstChild:Y.XmlElement|Y.XmlText|null</code></b>
+    <dd></dd>
     <b><code>insert(index:number, content:Array&lt;Y.XmlElement|Y.XmlText&gt;)</code></b>
     <dd></dd>
     <b><code>delete(index:number, length:number)</code></b>
     <dd></dd>
     <b><code>get(index:number)</code></b>
     <dd></dd>
+    <b><code>slice(start:number, end:number):Array&lt;Y.XmlElement|Y.XmlText&gt;</code></b>
+    <dd>Retrieve a range of content</dd>
     <b><code>length:number</code></b>
     <dd></dd>
+    <b><code>clone():Y.XmlFragment</code></b>
+    <dd>Clone this type into a fresh Yjs type.</dd>
     <b><code>toArray():Array&lt;Y.XmlElement|Y.XmlText&gt;</code></b>
     <dd>Copies the children to a new Array.</dd>
     <b><code>toDOM():DocumentFragment</code></b>
@@ -496,6 +517,14 @@ content and be actually XML compliant.
   </p>
   <pre><code>const yxml = new Y.XmlElement()</code></pre>
   <dl>
+    <b><code>parent:Y.AbstractType|null</code></b>
+    <dd></dd>
+    <b><code>firstChild:Y.XmlElement|Y.XmlText|null</code></b>
+    <dd></dd>
+    <b><code>nextSibling:Y.XmlElement|Y.XmlText|null</code></b>
+    <dd></dd>
+    <b><code>prevSibling:Y.XmlElement|Y.XmlText|null</code></b>
+    <dd></dd>
     <b><code>insert(index:number, content:Array&lt;Y.XmlElement|Y.XmlText&gt;)</code></b>
     <dd></dd>
     <b><code>delete(index:number, length:number)</code></b>
@@ -512,6 +541,12 @@ content and be actually XML compliant.
     <dd></dd>
     <b><code>getAttributes(attributeName:string):Object&lt;string,string&gt;</code></b>
     <dd></dd>
+    <b><code>get(i:number):Y.XmlElement|Y.XmlText</code></b>
+    <dd>Retrieve the i-th element.</dd>
+    <b><code>slice(start:number, end:number):Array&lt;Y.XmlElement|Y.XmlText&gt;</code></b>
+    <dd>Retrieve a range of content</dd>
+    <b><code>clone():Y.XmlElement</code></b>
+    <dd>Clone this type into a fresh Yjs type.</dd>
     <b><code>toArray():Array&lt;Y.XmlElement|Y.XmlText&gt;</code></b>
     <dd>Copies the children to a new Array.</dd>
     <b><code>toDOM():Element</code></b>

funding.cjs

@@ -0,0 +1,10 @@
+
+const log = require('lib0/dist/logging.cjs')
+
+log.print()
+log.print(log.BOLD, log.GREEN, log.BOLD, 'Thank you for using Yjs ', log.RED, '❤\n')
+log.print(
+  log.GREY,
+  'The project has grown considerably in the past year. Too much for me to maintain\nin my spare time. Several companies built their products with Yjs.\nYet, this project receives very little funding. Yjs is far from done. I want to\ncreate more awesome extensions and work on the growing number of open issues.\n', log.BOLD, 'Dear user, the future of this project entirely depends on you.\n')
+log.print(log.BLUE, log.BOLD, 'Please start funding the project now: https://github.com/sponsors/dmonad \n')
+log.print(log.GREY, '(This message will be removed when I achieved my funding goal)\n\n')

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "yjs",
-  "version": "13.4.0-0",
+  "version": "13.4.10",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "yjs",
-  "version": "13.4.0-0",
+  "version": "13.4.10",
   "description": "Shared Editing Library",
   "main": "./dist/yjs.cjs",
   "module": "./dist/yjs.mjs",
@@ -22,13 +22,15 @@
     "preversion": "npm run lint && PRODUCTION=1 npm run dist && npm run docs && node ./dist/tests.cjs --repitition-time 1000 && test -e dist/src/index.d.ts && test -e dist/yjs.cjs && test -e dist/yjs.cjs",
     "debug": "concurrently 'http-server -o test.html' 'npm run watch'",
     "trace-deopt": "clear && rollup -c  && node --trace-deopt dist/test.cjs",
-    "trace-opt": "clear && rollup -c  && node --trace-opt dist/test.cjs"
+    "trace-opt": "clear && rollup -c  && node --trace-opt dist/test.cjs",
+    "postinstall": "node ./funding.cjs"
   },
   "files": [
     "dist/*",
     "src/*",
     "tests/*",
-    "docs/*"
+    "docs/*",
+    "funding.cjs"
   ],
   "dictionaries": {
     "doc": "docs",

src/index.js

@@ -45,8 +45,10 @@ export {
   snapshot,
   emptySnapshot,
   findRootTypeKey,
+  getItem,
   typeListToArraySnapshot,
   typeMapGetSnapshot,
+  createDocFromSnapshot,
   iterateDeletedStructs,
   applyUpdate,
   applyUpdateV2,

src/structs/ContentString.js

@@ -51,6 +51,17 @@ export class ContentString {
   splice (offset) {
     const right = new ContentString(this.str.slice(offset))
     this.str = this.str.slice(0, offset)
+
+    // Prevent encoding invalid documents because of splitting of surrogate pairs: https://github.com/yjs/yjs/issues/248
+    const firstCharCode = this.str.charCodeAt(offset - 1)
+    if (firstCharCode >= 0xD800 && firstCharCode <= 0xDBFF) {
+      // Last character of the left split is the start of a surrogate utf16/ucs2 pair.
+      // We don't support splitting of surrogate pairs because this may lead to invalid documents.
+      // Replace the invalid character with a unicode replacement character (<28> / U+FFFD)
+      this.str = this.str.slice(0, offset - 1) + '<27>'
+      // replace right as well
+      right.str = '<27>' + right.str.slice(1)
+    }
     return right
   }
 

src/structs/Item.js

@@ -26,8 +26,6 @@ import {
 } from '../internals.js'
 
 import * as error from 'lib0/error.js'
-import * as maplib from 'lib0/map.js'
-import * as set from 'lib0/set.js'
 import * as binary from 'lib0/binary.js'
 
 /**
@@ -594,7 +592,7 @@ export class Item extends AbstractStruct {
       }
       this.markDeleted()
       addToDeleteSet(transaction.deleteSet, this.id.client, this.id.clock, this.length)
-      maplib.setIfUndefined(transaction.changed, parent, set.create).add(this.parentSub)
+      addChangedTypeToTransaction(transaction, parent, this.parentSub)
       this.content.delete(transaction)
     }
   }

src/types/AbstractType.js

@@ -287,6 +287,13 @@ export class AbstractType {
     this._searchMarker = null
   }
 
+  /**
+   * @return {AbstractType<any>|null}
+   */
+  get parent () {
+    return this._item ? /** @type {AbstractType<any>} */ (this._item.parent) : null
+  }
+
   /**
    * Integrate this type into the Yjs instance.
    *
@@ -309,6 +316,13 @@ export class AbstractType {
     throw error.methodUnimplemented()
   }
 
+  /**
+   * @return {AbstractType<EventType>}
+   */
+  clone () {
+    throw error.methodUnimplemented()
+  }
+
   /**
    * @param {AbstractUpdateEncoder} encoder
    */
@@ -381,6 +395,43 @@ export class AbstractType {
   toJSON () {}
 }
 
+/**
+ * @param {AbstractType<any>} type
+ * @param {number} start
+ * @param {number} end
+ * @return {Array<any>}
+ *
+ * @private
+ * @function
+ */
+export const typeListSlice = (type, start, end) => {
+  if (start < 0) {
+    start = type._length + start
+  }
+  if (end < 0) {
+    end = type._length + end
+  }
+  let len = end - start
+  const cs = []
+  let n = type._start
+  while (n !== null && len > 0) {
+    if (n.countable && !n.deleted) {
+      const c = n.content.getContent()
+      if (c.length <= start) {
+        start -= c.length
+      } else {
+        for (let i = start; i < c.length && len > 0; i++) {
+          cs.push(c[i])
+          len--
+        }
+        start = 0
+      }
+    }
+    n = n.right
+  }
+  return cs
+}
+
 /**
  * @param {AbstractType<any>} type
  * @return {Array<any>}

src/types/YArray.js

@@ -17,6 +17,7 @@ import {
   transact,
   ArraySearchMarker, AbstractUpdateDecoder, AbstractUpdateEncoder, Doc, Transaction, Item // eslint-disable-line
 } from '../internals.js'
+import { typeListSlice } from './AbstractType.js'
 
 /**
  * Event that describes the changes on a YArray
@@ -53,6 +54,18 @@ export class YArray extends AbstractType {
     this._searchMarker = []
   }
 
+  /**
+   * Construct a new YArray containing the specified items.
+   * @template T
+   * @param {Array<T>} items
+   * @return {YArray<T>}
+   */
+  static from (items) {
+    const a = new YArray()
+    a.push(items)
+    return a
+  }
+
   /**
    * Integrate this type into the Yjs instance.
    *
@@ -73,6 +86,17 @@ export class YArray extends AbstractType {
     return new YArray()
   }
 
+  /**
+   * @return {YArray<T>}
+   */
+  clone () {
+    const arr = new YArray()
+    arr.insert(0, this.toArray().map(el =>
+      el instanceof AbstractType ? el.clone() : el
+    ))
+    return arr
+  }
+
   get length () {
     return this._prelimContent === null ? this._length : this._prelimContent.length
   }
@@ -167,6 +191,17 @@ export class YArray extends AbstractType {
     return typeListToArray(this)
   }
 
+  /**
+   * Transforms this YArray to a JavaScript Array.
+   *
+   * @param {number} [start]
+   * @param {number} [end]
+   * @return {Array<T>}
+   */
+  slice (start = 0, end = this.length) {
+    return typeListSlice(this, start, end)
+  }
+
   /**
    * Transforms this Shared Type to a JSON object.
    *

src/types/YMap.js

@@ -84,6 +84,17 @@ export class YMap extends AbstractType {
     return new YMap()
   }
 
+  /**
+   * @return {YMap<T>}
+   */
+  clone () {
+    const map = new YMap()
+    this.forEach((value, key) => {
+      map.set(key, value instanceof AbstractType ? value.clone() : value)
+    })
+    return map
+  }
+
   /**
    * Creates YMapEvent and calls observers.
    *
@@ -132,9 +143,9 @@ export class YMap extends AbstractType {
   }
 
   /**
-   * Returns the keys for each element in the YMap Type.
+   * Returns the values for each element in the YMap Type.
    *
-   * @return {IterableIterator<string>}
+   * @return {IterableIterator<any>}
    */
   values () {
     return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => v[1].content.getContent()[v[1].length - 1])

src/types/YText.js

@@ -21,6 +21,10 @@ import {
   iterateDeletedStructs,
   iterateStructs,
   findMarker,
+  typeMapDelete,
+  typeMapSet,
+  typeMapGet,
+  typeMapGetAll,
   updateMarkerChanges,
   ArraySearchMarker, AbstractUpdateDecoder, AbstractUpdateEncoder, ID, Doc, Item, Snapshot, Transaction // eslint-disable-line
 } from '../internals.js'
@@ -165,6 +169,7 @@ const insertNegatedAttributes = (transaction, parent, currPos, negatedAttributes
   negatedAttributes.forEach((val, key) => {
     left = new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentFormat(key, val))
     left.integrate(transaction, 0)
+    currPos.currentAttributes.set(key, val)
   })
 }
 
@@ -512,13 +517,32 @@ export class YTextEvent extends YEvent {
   /**
    * @param {YText} ytext
    * @param {Transaction} transaction
+   * @param {Set<any>} subs The keys that changed
    */
-  constructor (ytext, transaction) {
+  constructor (ytext, transaction, subs) {
     super(ytext, transaction)
     /**
      * @type {Array<DeltaItem>|null}
      */
     this._delta = null
+    /**
+     * Whether the children changed.
+     * @type {Boolean}
+     * @private
+     */
+    this.childListChanged = false
+    /**
+     * Set of all changed attributes.
+     * @type {Set<string>}
+     */
+    this.keysChanged = new Set()
+    subs.forEach((sub) => {
+      if (sub === null) {
+        this.childListChanged = true
+      } else {
+        this.keysChanged.add(sub)
+      }
+    })
   }
 
   /**
@@ -762,6 +786,15 @@ export class YText extends AbstractType {
     return new YText()
   }
 
+  /**
+   * @return {YText}
+   */
+  clone () {
+    const text = new YText()
+    text.applyDelta(this.toDelta())
+    return text
+  }
+
   /**
    * Creates YTextEvent and calls observers.
    *
@@ -770,7 +803,7 @@ export class YText extends AbstractType {
    */
   _callObserver (transaction, parentSubs) {
     super._callObserver(transaction, parentSubs)
-    const event = new YTextEvent(this, transaction)
+    const event = new YTextEvent(this, transaction, parentSubs)
     const doc = transaction.doc
     // If a remote change happened, we try to cleanup potential formatting duplicates.
     if (!transaction.local) {
@@ -1102,6 +1135,74 @@ export class YText extends AbstractType {
     }
   }
 
+  /**
+   * Removes an attribute.
+   *
+   * @note Xml-Text nodes don't have attributes. You can use this feature to assign properties to complete text-blocks.
+   *
+   * @param {String} attributeName The attribute name that is to be removed.
+   *
+   * @public
+   */
+  removeAttribute (attributeName) {
+    if (this.doc !== null) {
+      transact(this.doc, transaction => {
+        typeMapDelete(transaction, this, attributeName)
+      })
+    } else {
+      /** @type {Array<function>} */ (this._pending).push(() => this.removeAttribute(attributeName))
+    }
+  }
+
+  /**
+   * Sets or updates an attribute.
+   *
+   * @note Xml-Text nodes don't have attributes. You can use this feature to assign properties to complete text-blocks.
+   *
+   * @param {String} attributeName The attribute name that is to be set.
+   * @param {any} attributeValue The attribute value that is to be set.
+   *
+   * @public
+   */
+  setAttribute (attributeName, attributeValue) {
+    if (this.doc !== null) {
+      transact(this.doc, transaction => {
+        typeMapSet(transaction, this, attributeName, attributeValue)
+      })
+    } else {
+      /** @type {Array<function>} */ (this._pending).push(() => this.setAttribute(attributeName, attributeValue))
+    }
+  }
+
+  /**
+   * Returns an attribute value that belongs to the attribute name.
+   *
+   * @note Xml-Text nodes don't have attributes. You can use this feature to assign properties to complete text-blocks.
+   *
+   * @param {String} attributeName The attribute name that identifies the
+   *                               queried value.
+   * @return {any} The queried attribute value.
+   *
+   * @public
+   */
+  getAttribute (attributeName) {
+    return /** @type {any} */ (typeMapGet(this, attributeName))
+  }
+
+  /**
+   * Returns all attribute name/value pairs in a JSON Object.
+   *
+   * @note Xml-Text nodes don't have attributes. You can use this feature to assign properties to complete text-blocks.
+   *
+   * @param {Snapshot} [snapshot]
+   * @return {Object<string, any>} A JSON Object that describes the attributes.
+   *
+   * @public
+   */
+  getAttributes (snapshot) {
+    return typeMapGetAll(this)
+  }
+
   /**
    * @param {AbstractUpdateEncoder} encoder
    */

src/types/YXmlElement.js

@@ -8,7 +8,7 @@ import {
   typeMapGetAll,
   typeListForEach,
   YXmlElementRefID,
-  AbstractUpdateDecoder, AbstractUpdateEncoder, Snapshot, Doc, Item // eslint-disable-line
+  YXmlText, ContentType, AbstractType, AbstractUpdateDecoder, AbstractUpdateEncoder, Snapshot, Doc, Item // eslint-disable-line
 } from '../internals.js'
 
 /**
@@ -28,6 +28,22 @@ export class YXmlElement extends YXmlFragment {
     this._prelimAttrs = new Map()
   }
 
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get nextSibling () {
+    const n = this._item ? this._item.next : null
+    return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
+  }
+
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get prevSibling () {
+    const n = this._item ? this._item.prev : null
+    return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
+  }
+
   /**
    * Integrate this type into the Yjs instance.
    *
@@ -55,6 +71,20 @@ export class YXmlElement extends YXmlFragment {
     return new YXmlElement(this.nodeName)
   }
 
+  /**
+   * @return {YXmlElement}
+   */
+  clone () {
+    const el = new YXmlElement(this.nodeName)
+    const attrs = this.getAttributes()
+    for (const key in attrs) {
+      el.setAttribute(key, attrs[key])
+    }
+    // @ts-ignore
+    el.insert(0, el.toArray().map(item => item instanceof AbstractType ? item.clone() : item))
+    return el
+  }
+
   /**
    * Returns the XML serialization of this YXmlElement.
    * The attributes are ordered by attribute-name, so you can easily use this

src/types/YXmlEvent.js

@@ -1,7 +1,7 @@
 
 import {
   YEvent,
-  YXmlElement, YXmlFragment, Transaction // eslint-disable-line
+  YXmlText, YXmlElement, YXmlFragment, Transaction // eslint-disable-line
 } from '../internals.js'
 
 /**
@@ -9,7 +9,7 @@ import {
  */
 export class YXmlEvent extends YEvent {
   /**
-   * @param {YXmlElement|YXmlFragment} target The target on which the event is created.
+   * @param {YXmlElement|YXmlText|YXmlFragment} target The target on which the event is created.
    * @param {Set<string|null>} subs The set of changed attributes. `null` is included if the
    *                   child list changed.
    * @param {Transaction} transaction The transaction instance with wich the
@@ -25,7 +25,7 @@ export class YXmlEvent extends YEvent {
     this.childListChanged = false
     /**
      * Set of all changed attributes.
-     * @type {Set<string|null>}
+     * @type {Set<string>}
      */
     this.attributesChanged = new Set()
     subs.forEach((sub) => {

src/types/YXmlFragment.js

@@ -9,14 +9,19 @@ import {
   typeListMap,
   typeListForEach,
   typeListInsertGenerics,
+  typeListInsertGenericsAfter,
   typeListDelete,
   typeListToArray,
   YXmlFragmentRefID,
   callTypeObservers,
   transact,
+  typeListGet,
+  typeListSlice,
   AbstractUpdateDecoder, AbstractUpdateEncoder, Doc, ContentType, Transaction, Item, YXmlText, YXmlHook, Snapshot // eslint-disable-line
 } from '../internals.js'
 
+import * as error from 'lib0/error.js'
+
 /**
  * Define the elements to which a set of CSS queries apply.
  * {@link https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Selectors|CSS_Selectors}
@@ -128,6 +133,14 @@ export class YXmlFragment extends AbstractType {
     this._prelimContent = []
   }
 
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get firstChild () {
+    const first = this._first
+    return first ? first.content.getContent()[0] : null
+  }
+
   /**
    * Integrate this type into the Yjs instance.
    *
@@ -148,6 +161,16 @@ export class YXmlFragment extends AbstractType {
     return new YXmlFragment()
   }
 
+  /**
+   * @return {YXmlFragment}
+   */
+  clone () {
+    const el = new YXmlFragment()
+    // @ts-ignore
+    el.insert(0, el.toArray().map(item => item instanceof AbstractType ? item.clone() : item))
+    return el
+  }
+
   get length () {
     return this._prelimContent === null ? this._length : this._prelimContent.length
   }
@@ -290,6 +313,32 @@ export class YXmlFragment extends AbstractType {
     }
   }
 
+  /**
+   * Inserts new content at an index.
+   *
+   * @example
+   *  // Insert character 'a' at position 0
+   *  xml.insert(0, [new Y.XmlText('text')])
+   *
+   * @param {null|Item|YXmlElement|YXmlText} ref The index to insert content at
+   * @param {Array<YXmlElement|YXmlText>} content The array of content
+   */
+  insertAfter (ref, content) {
+    if (this.doc !== null) {
+      transact(this.doc, transaction => {
+        const refItem = (ref && ref instanceof AbstractType) ? ref._item : ref
+        typeListInsertGenericsAfter(transaction, this, refItem, content)
+      })
+    } else {
+      const pc = /** @type {Array<any>} */ (this._prelimContent)
+      const index = ref === null ? 0 : pc.findIndex(el => el === ref) + 1
+      if (index === 0 && ref !== null) {
+        throw error.create('Reference item not found')
+      }
+      pc.splice(index, 0, ...content)
+    }
+  }
+
   /**
    * Deletes elements starting from an index.
    *
@@ -316,6 +365,45 @@ export class YXmlFragment extends AbstractType {
     return typeListToArray(this)
   }
 
+  /**
+   * Appends content to this YArray.
+   *
+   * @param {Array<YXmlElement|YXmlText>} content Array of content to append.
+   */
+  push (content) {
+    this.insert(this.length, content)
+  }
+
+  /**
+   * Preppends content to this YArray.
+   *
+   * @param {Array<YXmlElement|YXmlText>} content Array of content to preppend.
+   */
+  unshift (content) {
+    this.insert(0, content)
+  }
+
+  /**
+   * Returns the i-th element from a YArray.
+   *
+   * @param {number} index The index of the element to return from the YArray
+   * @return {YXmlElement|YXmlText}
+   */
+  get (index) {
+    return typeListGet(this, index)
+  }
+
+  /**
+   * Transforms this YArray to a JavaScript Array.
+   *
+   * @param {number} [start]
+   * @param {number} [end]
+   * @return {Array<YXmlElement|YXmlText>}
+   */
+  slice (start = 0, end = this.length) {
+    return typeListSlice(this, start, end)
+  }
+
   /**
    * Transform the properties of this type to binary and write it to an
    * BinaryEncoder.

src/types/YXmlHook.js

@@ -29,6 +29,17 @@ export class YXmlHook extends YMap {
     return new YXmlHook(this.hookName)
   }
 
+  /**
+   * @return {YXmlHook}
+   */
+  clone () {
+    const el = new YXmlHook(this.hookName)
+    this.forEach((value, key) => {
+      el.set(key, value)
+    })
+    return el
+  }
+
   /**
    * Creates a Dom Element that mirrors this YXmlElement.
    *

src/types/YXmlText.js

@@ -2,7 +2,7 @@
 import {
   YText,
   YXmlTextRefID,
-  AbstractUpdateDecoder, AbstractUpdateEncoder // eslint-disable-line
+  ContentType, YXmlElement, AbstractUpdateDecoder, AbstractUpdateEncoder // eslint-disable-line
 } from '../internals.js'
 
 /**
@@ -10,10 +10,35 @@ import {
  * simple formatting information like bold and italic.
  */
 export class YXmlText extends YText {
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get nextSibling () {
+    const n = this._item ? this._item.next : null
+    return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
+  }
+
+  /**
+   * @type {YXmlElement|YXmlText|null}
+   */
+  get prevSibling () {
+    const n = this._item ? this._item.prev : null
+    return n ? /** @type {YXmlElement|YXmlText} */ (/** @type {ContentType} */ (n.content).type) : null
+  }
+
   _copy () {
     return new YXmlText()
   }
 
+  /**
+   * @return {YXmlText}
+   */
+  clone () {
+    const text = new YXmlText()
+    text.applyDelta(this.toDelta())
+    return text
+  }
+
   /**
    * Creates a Dom Element that mirrors this YXmlText.
    *

src/utils/Doc.js

@@ -217,6 +217,9 @@ export class Doc extends Observable {
 
   /**
    * Converts the entire document into a js object, recursively traversing each yjs type
+   * Doesn't log types that have not been defined (using ydoc.getType(..)).
+   *
+   * @deprecated Do not use this method and rather call toJSON directly on the shared types.
    *
    * @return {Object<string, any>}
    */
@@ -257,6 +260,7 @@ export class Doc extends Observable {
       }, null, true)
     }
     this.emit('destroyed', [true])
+    this.emit('destroy', [this])
     super.destroy()
   }
 

src/utils/EventHandler.js

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

src/utils/PermanentUserData.js

@@ -51,7 +51,7 @@ export class PermanentUserData {
           })
         })
       })
-      this.dss.set(userDescription, mergeDeleteSets(ds.map(encodedDs => readDeleteSet(new DSDecoderV1(encodedDs)))))
+      this.dss.set(userDescription, mergeDeleteSets(ds.map(encodedDs => readDeleteSet(new DSDecoderV1(decoding.createDecoder(encodedDs))))))
       ids.observe(/** @param {YArrayEvent<any>} event */ event =>
         event.changes.added.forEach(item => item.content.getContent().forEach(addClientId))
       )

src/utils/RelativePosition.js

@@ -264,6 +264,7 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
 /**
  * @param {RelativePosition|null} a
  * @param {RelativePosition|null} b
+ * @return {boolean}
  *
  * @function
  */

src/utils/Snapshot.js

@@ -12,13 +12,17 @@ import {
   createDeleteSet,
   createID,
   getState,
-  AbstractDSDecoder, AbstractDSEncoder, DSEncoderV1, DSEncoderV2, DSDecoderV1, DSDecoderV2, Transaction, Doc, DeleteSet, Item // eslint-disable-line
+  findIndexSS,
+  UpdateEncoderV2,
+  DefaultDSEncoder,
+  applyUpdateV2,
+  AbstractDSDecoder, AbstractDSEncoder, DSEncoderV2, DSDecoderV1, DSDecoderV2, Transaction, Doc, DeleteSet, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as map from 'lib0/map.js'
 import * as set from 'lib0/set.js'
 import * as decoding from 'lib0/decoding.js'
-import { DefaultDSEncoder } from './encoding.js'
+import * as encoding from 'lib0/encoding.js'
 
 export class Snapshot {
   /**
@@ -148,3 +152,51 @@ export const splitSnapshotAffectedStructs = (transaction, snapshot) => {
     meta.add(snapshot)
   }
 }
+
+/**
+ * @param {Doc} originDoc
+ * @param {Snapshot} snapshot
+ * @param {Doc} [newDoc] Optionally, you may define the Yjs document that receives the data from originDoc
+ * @return {Doc}
+ */
+export const createDocFromSnapshot = (originDoc, snapshot, newDoc = new Doc()) => {
+  if (originDoc.gc) {
+    // we should not try to restore a GC-ed document, because some of the restored items might have their content deleted
+    throw new Error('originDoc must not be garbage collected')
+  }
+  const { sv, ds } = snapshot
+
+  const encoder = new UpdateEncoderV2()
+  originDoc.transact(transaction => {
+    let size = 0
+    sv.forEach(clock => {
+      if (clock > 0) {
+        size++
+      }
+    })
+    encoding.writeVarUint(encoder.restEncoder, size)
+    // splitting the structs before writing them to the encoder
+    for (const [client, clock] of sv) {
+      if (clock === 0) {
+        continue
+      }
+      if (clock < getState(originDoc.store, client)) {
+        getItemCleanStart(transaction, createID(client, clock))
+      }
+      const structs = originDoc.store.clients.get(client) || []
+      const lastStructIndex = findIndexSS(structs, clock - 1)
+      // write # encoded structs
+      encoding.writeVarUint(encoder.restEncoder, lastStructIndex + 1)
+      encoder.writeClient(client)
+      // first clock written is 0
+      encoding.writeVarUint(encoder.restEncoder, 0)
+      for (let i = 0; i <= lastStructIndex; i++) {
+        structs[i].write(encoder, 0)
+      }
+    }
+    writeDeleteSet(encoder, ds)
+  })
+
+  applyUpdateV2(newDoc, encoder.toUint8Array(), 'snapshot')
+  return newDoc
+}

src/utils/Transaction.js

@@ -284,6 +284,9 @@ const cleanupTransactions = (transactionCleanups, i) => {
                 .forEach(event => {
                   event.currentTarget = type
                 })
+              // sort events by path length so that top-level events are fired first.
+              events
+                .sort((event1, event2) => event1.path.length - event2.path.length)
               // We don't need to check for events.length
               // because we know it has at least one element
               callEventHandlerListeners(type._dEH, events, transaction)

src/utils/UndoManager.js

@@ -119,11 +119,17 @@ const popStackItem = (undoManager, stack, eventType) => {
         }
       }
       result = stackItem
+    }
+    transaction.changed.forEach((subProps, type) => {
+      // destroy search marker if necessary
+      if (subProps.has(null) && type._searchMarker) {
+        type._searchMarker.length = 0
+      }
+    })
+  }, undoManager)
   if (result != null) {
     undoManager.emit('stack-item-popped', [{ stackItem: result, type: eventType }, undoManager])
   }
-    }
-  }, undoManager)
   return result
 }
 
@@ -151,10 +157,7 @@ export class UndoManager extends Observable {
    * @param {AbstractType<any>|Array<AbstractType<any>>} typeScope Accepts either a single type, or an array of types
    * @param {UndoManagerOptions} options
    */
-  constructor (typeScope, { captureTimeout, deleteFilter = () => true, trackedOrigins = new Set([null]) } = {}) {
-    if (captureTimeout == null) {
-      captureTimeout = 500
-    }
+  constructor (typeScope, { captureTimeout = 500, deleteFilter = () => true, trackedOrigins = new Set([null]) } = {}) {
     super()
     this.scope = typeScope instanceof Array ? typeScope : [typeScope]
     this.deleteFilter = deleteFilter

src/utils/YEvent.js

@@ -40,6 +40,8 @@ export class YEvent {
   /**
    * Computes the path from `y` to the changed type.
    *
+   * @todo v14 should standardize on path: Array<{parent, index}> because that is easier to work with.
+   *
    * The following property holds:
    * @example
    *   let type = y
@@ -78,7 +80,7 @@ export class YEvent {
   }
 
   /**
-   * @return {{added:Set<Item>,deleted:Set<Item>,delta:Array<{insert:Array<any>}|{delete:number}|{retain:number}>}}
+   * @return {{added:Set<Item>,deleted:Set<Item>,keys:Map<string,{action:'add'|'update'|'delete',oldValue:any}>,delta:Array<{insert:Array<any>}|{delete:number}|{retain:number}>}}
    */
   get changes () {
     let changes = this._changes

tests/encoding.tests.js

@@ -1,4 +1,5 @@
 import * as t from 'lib0/testing.js'
+import * as promise from 'lib0/promise.js'
 
 import {
   contentRefs,
@@ -10,7 +11,11 @@ import {
   readContentType,
   readContentFormat,
   readContentAny,
-  readContentDoc
+  readContentDoc,
+  Doc,
+  PermanentUserData,
+  encodeStateAsUpdate,
+  applyUpdate
 } from '../src/internals.js'
 
 /**
@@ -28,3 +33,31 @@ export const testStructReferences = tc => {
   t.assert(contentRefs[8] === readContentAny)
   t.assert(contentRefs[9] === readContentDoc)
 }
+
+/**
+ * There is some custom encoding/decoding happening in PermanentUserData.
+ * This is why it landed here.
+ *
+ * @param {t.TestCase} tc
+ */
+export const testPermanentUserData = async tc => {
+  const ydoc1 = new Doc()
+  const ydoc2 = new Doc()
+  const pd1 = new PermanentUserData(ydoc1)
+  const pd2 = new PermanentUserData(ydoc2)
+  pd1.setUserMapping(ydoc1, ydoc1.clientID, 'user a')
+  pd2.setUserMapping(ydoc2, ydoc2.clientID, 'user b')
+  ydoc1.getText().insert(0, 'xhi')
+  ydoc1.getText().delete(0, 1)
+  ydoc2.getText().insert(0, 'hxxi')
+  ydoc2.getText().delete(1, 2)
+  await promise.wait(10)
+  applyUpdate(ydoc2, encodeStateAsUpdate(ydoc1))
+  applyUpdate(ydoc1, encodeStateAsUpdate(ydoc2))
+
+  // now sync a third doc with same name as doc1 and then create PermanentUserData
+  const ydoc3 = new Doc()
+  applyUpdate(ydoc3, encodeStateAsUpdate(ydoc1))
+  const pd3 = new PermanentUserData(ydoc3)
+  pd3.setUserMapping(ydoc3, ydoc3.clientID, 'user a')
+}

tests/index.js

@@ -7,6 +7,7 @@ import * as encoding from './encoding.tests.js'
 import * as undoredo from './undo-redo.tests.js'
 import * as compatibility from './compatibility.tests.js'
 import * as doc from './doc.tests.js'
+import * as snapshot from './snapshot.tests.js'
 
 import { runTests } from 'lib0/testing.js'
 import { isBrowser, isNode } from 'lib0/environment.js'
@@ -16,7 +17,7 @@ if (isBrowser) {
   log.createVConsole(document.body)
 }
 runTests({
-  doc, map, array, text, xml, encoding, undoredo, compatibility
+  doc, map, array, text, xml, encoding, undoredo, compatibility, snapshot
 }).then(success => {
   /* istanbul ignore next */
   if (isNode) {

tests/snapshot.tests.js

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

tests/undo-redo.tests.js

@@ -53,6 +53,28 @@ export const testUndoText = tc => {
   t.compare(text0.toDelta(), [{ insert: 'b' }, { insert: 'cxy', attributes: { bold: true } }, { insert: 'z' }])
 }
 
+/**
+ * Test case to fix #241
+ * @param {t.TestCase} tc
+ */
+export const testDoubleUndo = tc => {
+  const doc = new Y.Doc()
+  const text = doc.getText()
+  text.insert(0, '1221')
+
+  const manager = new Y.UndoManager(text)
+
+  text.insert(2, '3')
+  text.insert(3, '3')
+
+  manager.undo()
+  manager.undo()
+
+  text.insert(2, '3')
+
+  t.compareStrings(text.toString(), '12321')
+}
+
 /**
  * @param {t.TestCase} tc
  */

tests/y-array.tests.js

@@ -17,6 +17,21 @@ export const testBasicUpdate = tc => {
   t.compare(doc2.getArray('array').toArray(), ['hi'])
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSlice = tc => {
+  const doc1 = new Y.Doc()
+  const arr = doc1.getArray('array')
+  arr.insert(0, [1, 2, 3])
+  t.compareArrays(arr.slice(0), [1, 2, 3])
+  t.compareArrays(arr.slice(1), [2, 3])
+  t.compareArrays(arr.slice(0, -1), [1, 2])
+  arr.insert(0, [0])
+  t.compareArrays(arr.slice(0), [0, 1, 2, 3])
+  t.compareArrays(arr.slice(0, 2), [0, 1])
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -204,6 +219,34 @@ export const testInsertAndDeleteEventsForTypes = tc => {
   compare(users)
 }
 
+/**
+ * This issue has been reported in https://discuss.yjs.dev/t/order-in-which-events-yielded-by-observedeep-should-be-applied/261/2
+ *
+ * Deep observers generate multiple events. When an array added at item at, say, position 0,
+ * and item 1 changed then the array-add event should fire first so that the change event
+ * path is correct. A array binding might lead to an inconsistent state otherwise.
+ *
+ * @param {t.TestCase} tc
+ */
+export const testObserveDeepEventOrder = tc => {
+  const { array0, users } = init(tc, { users: 2 })
+  /**
+   * @type {Array<any>}
+   */
+  let events = []
+  array0.observeDeep(e => {
+    events = e
+  })
+  array0.insert(0, [new Y.Map()])
+  users[0].transact(() => {
+    array0.get(0).set('a', 'a')
+    array0.insert(0, [0])
+  })
+  for (let i = 1; i < events.length; i++) {
+    t.assert(events[i - 1].path.length <= events[i].path.length, 'path size increases, fire top-level events first')
+  }
+}
+
 /**
  * @param {t.TestCase} tc
  */

tests/y-text.tests.js

@@ -78,6 +78,29 @@ export const testBasicFormat = tc => {
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testMultilineFormat = tc => {
+  const ydoc = new Y.Doc()
+  const testText = ydoc.getText('test')
+  testText.insert(0, 'Test\nMulti-line\nFormatting')
+  testText.applyDelta([
+    { retain: 4, attributes: { bold: true } },
+    { retain: 1 }, // newline character
+    { retain: 10, attributes: { bold: true } },
+    { retain: 1 }, // newline character
+    { retain: 10, attributes: { bold: true } }
+  ])
+  t.compare(testText.toDelta(), [
+    { insert: 'Test', attributes: { bold: true } },
+    { insert: '\n' },
+    { insert: 'Multi-line', attributes: { bold: true } },
+    { insert: '\n' },
+    { insert: 'Formatting', attributes: { bold: true } }
+  ])
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -249,6 +272,8 @@ export const testAppendChars = tc => {
   t.assert(text0.length === N)
 }
 
+const largeDocumentSize = 100000
+
 const id = Y.createID(0, 0)
 const c = new Y.ContentString('a')
 
@@ -256,7 +281,7 @@ const c = new Y.ContentString('a')
  * @param {t.TestCase} tc
  */
 export const testBestCase = tc => {
-  const N = 2000000
+  const N = largeDocumentSize
   const items = new Array(N)
   t.measureTime('time to create two million items in the best case', () => {
     const parent = /** @type {any} */ ({})
@@ -284,7 +309,9 @@ export const testBestCase = tc => {
 }
 
 const tryGc = () => {
+  // @ts-ignore
   if (typeof global !== 'undefined' && global.gc) {
+    // @ts-ignore
     global.gc()
   }
 }
@@ -293,7 +320,7 @@ const tryGc = () => {
  * @param {t.TestCase} tc
  */
 export const testLargeFragmentedDocument = tc => {
-  const itemsToInsert = 1000000
+  const itemsToInsert = largeDocumentSize
   let update = /** @type {any} */ (null)
   ;(() => {
     const doc1 = new Y.Doc()
@@ -321,6 +348,40 @@ export const testLargeFragmentedDocument = tc => {
   })()
 }
 
+/**
+ * Splitting surrogates can lead to invalid encoded documents.
+ *
+ * https://github.com/yjs/yjs/issues/248
+ *
+ * @param {t.TestCase} tc
+ */
+export const testSplitSurrogateCharacter = tc => {
+  {
+    const { users, text0 } = init(tc, { users: 2 })
+    users[1].disconnect() // disconnecting forces the user to encode the split surrogate
+    text0.insert(0, '👾') // insert surrogate character
+    // split surrogate, which should not lead to an encoding error
+    text0.insert(1, 'hi!')
+    compare(users)
+  }
+  {
+    const { users, text0 } = init(tc, { users: 2 })
+    users[1].disconnect() // disconnecting forces the user to encode the split surrogate
+    text0.insert(0, '👾👾') // insert surrogate character
+    // partially delete surrogate
+    text0.delete(1, 2)
+    compare(users)
+  }
+  {
+    const { users, text0 } = init(tc, { users: 2 })
+    users[1].disconnect() // disconnecting forces the user to encode the split surrogate
+    text0.insert(0, '👾👾') // insert surrogate character
+    // formatting will also split surrogates
+    text0.format(1, 2, { bold: true })
+    compare(users)
+  }
+}
+
 // RANDOM TESTS
 
 let charCounter = 0

tests/y-xml.tests.js

@@ -73,3 +73,63 @@ export const testTreewalker = tc => {
   t.assert(xml0.querySelector('p') === paragraph1, 'querySelector found paragraph1')
   compare(users)
 }
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testYtextAttributes = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = /** @type {Y.XmlText} */ (ydoc.get('', Y.XmlText))
+  ytext.observe(event => {
+    t.compare(event.changes.keys.get('test'), { action: 'add', oldValue: undefined })
+  })
+  ytext.setAttribute('test', 42)
+  t.compare(ytext.getAttribute('test'), 42)
+  t.compare(ytext.getAttributes(), { test: 42 })
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSiblings = tc => {
+  const ydoc = new Y.Doc()
+  const yxml = ydoc.getXmlFragment()
+  const first = new Y.XmlText()
+  const second = new Y.XmlElement('p')
+  yxml.insert(0, [first, second])
+  t.assert(first.nextSibling === second)
+  t.assert(second.prevSibling === first)
+  t.assert(first.parent === yxml)
+  t.assert(yxml.parent === null)
+  t.assert(yxml.firstChild === first)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testInsertafter = tc => {
+  const ydoc = new Y.Doc()
+  const yxml = ydoc.getXmlFragment()
+  const first = new Y.XmlText()
+  const second = new Y.XmlElement('p')
+  const third = new Y.XmlElement('p')
+
+  const deepsecond1 = new Y.XmlElement('span')
+  const deepsecond2 = new Y.XmlText()
+  second.insertAfter(null, [deepsecond1])
+  second.insertAfter(deepsecond1, [deepsecond2])
+
+  yxml.insertAfter(null, [first, second])
+  yxml.insertAfter(second, [third])
+
+  t.assert(yxml.length === 3)
+  t.assert(second.get(0) === deepsecond1)
+  t.assert(second.get(1) === deepsecond2)
+
+  t.compareArrays(yxml.toArray(), [first, second, third])
+
+  t.fails(() => {
+    const el = new Y.XmlElement('p')
+    el.insertAfter(deepsecond1, [new Y.XmlText()])
+  })
+}