Merge pull request #628 from angelo-v/patch-1

Update README.md

.github/FUNDING.yml

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

.github/workflows/nodejs.yml

@@ -0,0 +1,31 @@
+# This workflow will do a clean install of node dependencies, build the source code and run tests across different versions of node
+# For more information see: https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
+
+name: Node.js CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [10.x, 12.x, 13.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: npm ci
+    - run: npm run lint
+    - run: npm run test-extensive
+      env:
+        CI: true

README.md

@@ -15,13 +15,54 @@ suited for even large documents.
 
 * Demos: [https://github.com/yjs/yjs-demos](https://github.com/yjs/yjs-demos)
 * Discuss: [https://discuss.yjs.dev](https://discuss.yjs.dev)
-* Benchmarks:
+* Benchmark Yjs vs. Automerge:
   [https://github.com/dmonad/crdt-benchmarks](https://github.com/dmonad/crdt-benchmarks)
 * Podcast [**"Yjs Deep Dive into real time collaborative editing solutions":**](https://www.tag1consulting.com/blog/deep-dive-real-time-collaborative-editing-solutions-tagteamtalk-001-0)
 * Podcast [**"Google Docs-style editing in Gutenberg with the YJS framework":**](https://publishpress.com/blog/yjs/)
 
-:construction_worker_woman: If you are looking for professional support to build
+:construction_worker_woman: If you are looking for professional (paid) support to
-collaborative or distributed applications ping us at <yjs@tag1consulting.com>.
+build collaborative or distributed applications ping us at
+<yjs@tag1consulting.com>. Otherwise you can find help on our
+[discussion board](https://discuss.yjs.dev).
+
+## Sponsors
+
+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/)
+[![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)
+
+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
+  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/)
+  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:
+* [Nimbus Note](https://nimbusweb.me/note.php) A note-taking app designed by
+  Nimbus Web.
+* [JoeDocs](https://joedocs.com/) An open collaborative wiki.
+* [Pluxbox RadioManager](https://pluxbox.com/) A web-based app to
+  collaboratively organize radio broadcasts.
+* [Cattaz](http://cattaz.io/) A wiki that can run custom applications in the
+  wiki pages.
+* [Evernote](https://evernote.com) A note-taking and task management application.
 
 ## Table of Contents
 
@@ -38,12 +79,6 @@ collaborative or distributed applications ping us at <yjs@tag1consulting.com>.
 * [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
@@ -56,13 +91,10 @@ 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://yjs-demos.now.sh/prosemirror/) |
+| [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://yjs-demos.now.sh/quill/) |
+| [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://yjs-demos.now.sh/codemirror/) |
+| [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://yjs-demos.now.sh/monaco/) |
+| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](http://github.com/yjs/y-monaco) | [demo](https://demos.yjs.dev/monaco/monaco.html) |
-| [Ace](https://ace.c9.io/) | | [y-ace](http://github.com/yjs/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/yjs/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/yjs/y-dom) | [demo](https://yjs-demos.now.sh/dom/) |
 
 ### Providers
 
@@ -112,7 +144,7 @@ npm i yjs y-websocket
 Start the y-websocket server:
 
 ```sh
-PORT=1234 node ./node_modules/y-websocket/bin/server.js
+PORT=1234 node ./node_modules/y-websocket/bin/server.cjs
 ```
 
 ### Example: Observe types
@@ -144,6 +176,54 @@ Now you understand how types are defined on a shared document. Next you can jump
 to the [demo repository](https://github.com/yjs/yjs-demos) or continue reading
 the API docs.
 
+### Example: Using and combining providers
+
+Any of the Yjs providers can be combined with each other. So you can sync data
+over different network technologies.
+
+In most cases you want to use a network provider (like y-websocket or y-webrtc)
+in combination with a persistence provider (y-indexeddb in the browser).
+Persistence allows you to load the document faster and to persist data that is
+created while offline.
+
+For the sake of this demo we combine two different network providers with a
+persistence provider.
+
+```js
+import * as Y from 'yjs'
+import { WebrtcProvider } from 'y-webrtc'
+import { WebsocketProvider } from 'y-websocket'
+import { IndexeddbPersistence } from 'y-indexeddb'
+
+const ydoc = new Y.Doc()
+
+// this allows you to instantly get the (cached) documents data
+const indexeddbProvider = new IndexeddbPersistence('count-demo', ydoc)
+idbP.whenSynced.then(() => {
+  console.log('loaded data from indexed db')
+})
+
+// Sync clients with the y-webrtc provider.
+const webrtcProvider = new WebrtcProvider('count-demo', ydoc)
+
+// Sync clients with the y-websocket provider
+const websocketProvider = new WebsocketProvider(
+  'wss://demos.yjs.dev', 'count-demo', ydoc
+)
+
+// array of numbers which produce a sum
+const yarray = ydoc.getArray('count')
+
+// observe changes of the sum
+yarray.observe(event => {
+  // print updates when the data changes
+  console.log('new sum: ' + yarray.toArray().reduce((a,b) => a + b))
+})
+
+// add 1 to the sum
+yarray.push([1]) // => "new sum: 1"
+```
+
 ## API
 
 ```js
@@ -165,11 +245,13 @@ necessary.
     <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
+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>unshift(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>
@@ -315,8 +397,12 @@ YTextEvents compute changes as deltas.
     <dd></dd>
     <b><code>format(index:number, length:number, formattingAttributes:Object&lt;string,string&gt;)</code></b>
     <dd>Assign formatting attributes to a range in the text</dd>
-    <b><code>applyDelta(delta)</code></b>
+    <b><code>applyDelta(delta, opts:Object&lt;string,any&gt;)</code></b>
-    <dd>See <a href="https://quilljs.com/docs/delta/">Quill Delta</a></dd>
+    <dd>
+        See <a href="https://quilljs.com/docs/delta/">Quill Delta</a>
+        Can set options for preventing remove ending newLines, default is true.
+        <pre>ytext.applyDelta(delta, { sanitize: false })</pre>
+    </dd>
     <b><code>length:number</code></b>
     <dd></dd>
     <b><code>toString():string</code></b>
@@ -470,6 +556,12 @@ const doc = new Y.Doc()
 <dl>
   <b><code>clientID</code></b>
   <dd>A unique id that identifies this client. (readonly)</dd>
+  <b><code>gc</code></b>
+  <dd>
+Whether garbage collection is enabled on this doc instance. Set `doc.gc = false`
+in order to disable gc and be able to restore old content. See https://github.com/yjs/yjs#yjs-crdt-algorithm
+for more information about gc in Yjs.
+  </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
@@ -553,7 +645,7 @@ Y.applyUpdate(ydoc2, state1)
 This example shows how to sync two clients with the minimal amount of exchanged
 data by computing only the differences using the state vector of the remote
 client. Syncing clients using the state vector requires another roundtrip, but
-can safe a lot of bandwidth.
+can save a lot of bandwidth.
 
 ```js
 const stateVector1 = Y.encodeStateVector(ydoc1)
@@ -642,11 +734,11 @@ pos.index === 2 // => true
 
 ### Y.UndoManager
 
-Yjs ships with an Undo/Redo manager for selective undo/redo of of changes on a
+Yjs ships with an Undo/Redo manager for selective undo/redo of changes on a
 Yjs type. The changes can be optionally scoped to transaction origins.
 
 ```js
-const ytext = doc.getArray('array')
+const ytext = doc.getText('text')
 const undoManager = new Y.UndoManager(ytext)
 
 ytext.insert(0, 'abc')
@@ -657,8 +749,8 @@ ytext.toString() // => 'abc'
 ```
 
 <dl>
-  <b><code>constructor(scope:Y.AbstractType|Array&lt;Y.AbstractType&gt;,
+  <b><code>constructor(scope:Y.AbstractType|Array&lt;Y.AbstractType&gt;
-  [[{captureTimeout:number,trackedOrigins:Set&lt;any&gt;,deleteFilter:function(item):boolean}]])</code></b>
+  [, {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>
@@ -698,28 +790,30 @@ StackItem won't be merged.
 // without stopCapturing
 ytext.insert(0, 'a')
 ytext.insert(1, 'b')
-um.undo()
+undoManager.undo()
 ytext.toString() // => '' (note that 'ab' was removed)
 // with stopCapturing
 ytext.insert(0, 'a')
-um.stopCapturing()
+undoManager.stopCapturing()
 ytext.insert(0, 'b')
-um.undo()
+undoManager.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
+it defaults to `null`. By specifying `trackedOrigins` you can
 selectively specify which changes should be tracked by `UndoManager`. The
-UndoManager instance is always added to `trackedTransactionOrigins`.
+UndoManager instance is always added to `trackedOrigins`.
 
 ```js
 class CustomBinding {}
 
-const ytext = doc.getArray('array')
+const ytext = doc.getText('text')
-const undoManager = new Y.UndoManager(ytext, new Set([42, CustomBinding]))
+const undoManager = new Y.UndoManager(ytext, {
+  trackedOrigins: new Set([42, CustomBinding])
+})
 
 ytext.insert(0, 'abc')
 undoManager.undo()
@@ -756,8 +850,10 @@ additional meta information like the cursor location or the view on the
 document. You can assign meta-information to Undo-/Redo-StackItems.
 
 ```js
-const ytext = doc.getArray('array')
+const ytext = doc.getText('text')
-const undoManager = new Y.UndoManager(ytext, new Set([42, CustomBinding]))
+const undoManager = new Y.UndoManager(ytext, {
+  trackedOrigins: new Set([42, CustomBinding])
+})
 
 undoManager.on('stack-item-added', event => {
   // save the current cursor location on the stack-item

package.json

@@ -1,11 +1,15 @@
 {
   "name": "yjs",
-  "version": "13.0.2",
+  "version": "13.2.0",
   "description": "Shared Editing Library",
   "main": "./dist/yjs.cjs",
-  "module": "./src/index.js",
+  "module": "./dist/yjs.mjs",
   "types": "./dist/src/index.d.ts",
   "sideEffects": false,
+  "funding": {
+    "type": "GitHub Sponsors ❤",
+    "url": "https://github.com/sponsors/dmonad"
+  },
   "scripts": {
     "test": "npm run dist && node ./dist/tests.cjs --repitition-time 50",
     "test-extensive": "npm run lint && npm run dist && node ./dist/tests.cjs --production --repitition-time 10000",
@@ -56,20 +60,20 @@
   },
   "homepage": "https://yjs.dev",
   "dependencies": {
-    "lib0": "^0.2.12"
+    "lib0": "^0.2.27"
   },
   "devDependencies": {
-    "@rollup/plugin-commonjs": "^11.0.1",
+    "@rollup/plugin-commonjs": "^11.1.0",
-    "@rollup/plugin-node-resolve": "^7.0.0",
+    "@rollup/plugin-node-resolve": "^7.1.3",
     "concurrently": "^3.6.1",
-    "http-server": "^0.12.1",
+    "http-server": "^0.12.3",
-    "jsdoc": "^3.6.3",
+    "jsdoc": "^3.6.4",
-    "markdownlint-cli": "^0.19.0",
+    "markdownlint-cli": "^0.23.1",
-    "rollup": "^1.30.0",
+    "rollup": "^1.32.1",
     "rollup-cli": "^1.0.9",
-    "standard": "^14.0.0",
+    "standard": "^14.3.4",
     "tui-jsdoc-template": "^1.2.2",
-    "typescript": "^3.7.5",
+    "typescript": "^3.9.3",
-    "y-protocols": "^0.2.0"
+    "y-protocols": "^0.2.3"
   }
 }

rollup.config.js

@@ -51,6 +51,15 @@ export default [{
     }
   },
   external: id => /^lib0\//.test(id)
+}, {
+  input: './src/index.js',
+  output: {
+    name: 'Y',
+    file: 'dist/yjs.mjs',
+    format: 'esm',
+    sourcemap: true
+  },
+  external: id => /^lib0\//.test(id)
 }, {
   input: './tests/index.js',
   output: {
@@ -62,7 +71,6 @@ export default [{
   plugins: [
     debugResolve,
     nodeResolve({
-      sourcemap: true,
       mainFields: ['module', 'browser', 'main']
     }),
     commonjs()
@@ -78,7 +86,6 @@ export default [{
   plugins: [
     debugResolve,
     nodeResolve({
-      sourcemap: true,
       mainFields: ['module', 'main']
     }),
     commonjs()

src/index.js

@@ -26,6 +26,7 @@ export {
   ContentType,
   AbstractType,
   RelativePosition,
+  getTypeChildren,
   createRelativePositionFromTypeIndex,
   createRelativePositionFromJSON,
   createAbsolutePositionFromRelativePosition,
@@ -47,6 +48,7 @@ export {
   typeMapGetSnapshot,
   iterateDeletedStructs,
   applyUpdate,
+  readUpdate,
   encodeStateAsUpdate,
   encodeStateVector,
   UndoManager,
@@ -56,5 +58,6 @@ export {
   isParentOf,
   equalSnapshots,
   PermanentUserData, // @TODO experimental
-  tryGc
+  tryGc,
+  transact
 } from './internals.js'

src/structs/AbstractStruct.js

@@ -6,23 +6,21 @@ import {
 import * as encoding from 'lib0/encoding.js' // eslint-disable-line
 import * as error from 'lib0/error.js'
 
-/**
- * @private
- */
 export class AbstractStruct {
   /**
    * @param {ID} id
    * @param {number} length
    */
   constructor (id, length) {
-    /**
-     * The uniqe identifier of this struct.
-     * @type {ID}
-     * @readonly
-     */
     this.id = id
     this.length = length
-    this.deleted = false
+  }
+
+  /**
+   * @type {boolean}
+   */
+  get deleted () {
+    throw error.methodUnimplemented()
   }
 
   /**
@@ -40,7 +38,6 @@ export class AbstractStruct {
    * @param {encoding.Encoder} encoder The encoder to write data to.
    * @param {number} offset
    * @param {number} encodingRef
-   * @private
    */
   write (encoder, offset, encodingRef) {
     throw error.methodUnimplemented()
@@ -48,46 +45,9 @@ export class AbstractStruct {
 
   /**
    * @param {Transaction} transaction
-   */
-  integrate (transaction) {
-    throw error.methodUnimplemented()
-  }
-}
-
-/**
- * @private
- */
-export class AbstractStructRef {
-  /**
-   * @param {ID} id
-   */
-  constructor (id) {
-    /**
-     * @type {Array<ID>}
-     */
-    this._missing = []
-    /**
-     * The uniqe identifier of this type.
-     * @type {ID}
-     */
-    this.id = id
-  }
-
-  /**
-   * @param {Transaction} transaction
-   * @return {Array<ID|null>}
-   */
-  getMissing (transaction) {
-    return this._missing
-  }
-
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
    * @param {number} offset
-   * @return {AbstractStruct}
    */
-  toStruct (transaction, store, offset) {
+  integrate (transaction, offset) {
     throw error.methodUnimplemented()
   }
 }

src/structs/ContentAny.js

@@ -5,9 +5,6 @@ import {
 import * as encoding from 'lib0/encoding.js'
 import * as decoding from 'lib0/decoding.js'
 
-/**
- * @private
- */
 export class ContentAny {
   /**
    * @param {Array<any>} arr
@@ -101,8 +98,6 @@ export class ContentAny {
 }
 
 /**
- * @private
- *
  * @param {decoding.Decoder} decoder
  * @return {ContentAny}
  */

src/structs/ContentBinary.js

@@ -7,9 +7,6 @@ import * as decoding from 'lib0/decoding.js'
 import * as buffer from 'lib0/buffer.js'
 import * as error from 'lib0/error.js'
 
-/**
- * @private
- */
 export class ContentBinary {
   /**
    * @param {Uint8Array} content
@@ -92,8 +89,6 @@ export class ContentBinary {
 }
 
 /**
- * @private
- *
  * @param {decoding.Decoder} decoder
  * @return {ContentBinary}
  */

src/structs/ContentDeleted.js

@@ -7,9 +7,6 @@ import {
 import * as encoding from 'lib0/encoding.js'
 import * as decoding from 'lib0/decoding.js'
 
-/**
- * @private
- */
 export class ContentDeleted {
   /**
    * @param {number} len
@@ -71,7 +68,7 @@ export class ContentDeleted {
    */
   integrate (transaction, item) {
     addToDeleteSet(transaction.deleteSet, item.id, this.len)
-    item.deleted = true
+    item.markDeleted()
   }
 
   /**

src/structs/ContentFormat.js

@@ -95,8 +95,6 @@ export class ContentFormat {
 }
 
 /**
- * @private
- *
  * @param {decoding.Decoder} decoder
  * @return {ContentFormat}
  */

src/structs/ContentType.js

@@ -7,7 +7,7 @@ import {
   readYXmlFragment,
   readYXmlHook,
   readYXmlText,
-  StructStore, Transaction, Item, YEvent, AbstractType // eslint-disable-line
+  ID, StructStore, Transaction, Item, YEvent, AbstractType // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js' // eslint-disable-line
@@ -115,7 +115,7 @@ export class ContentType {
         // We try to merge all deleted items after each transaction,
         // but we have no knowledge about that this needs to be merged
         // since it is not in transaction.ds. Hence we add it to transaction._mergeStructs
-        transaction._mergeStructs.add(item.id)
+        transaction._mergeStructs.push(item)
       }
       item = item.right
     }
@@ -124,7 +124,7 @@ export class ContentType {
         item.delete(transaction)
       } else {
         // same as above
-        transaction._mergeStructs.add(item.id)
+        transaction._mergeStructs.push(item)
       }
     })
     transaction.changed.delete(this.type)

src/structs/GC.js

@@ -1,13 +1,10 @@
 
 import {
-  AbstractStructRef,
   AbstractStruct,
-  createID,
   addStruct,
   StructStore, Transaction, ID // eslint-disable-line
 } from '../internals.js'
 
-import * as decoding from 'lib0/decoding.js'
 import * as encoding from 'lib0/encoding.js'
 
 export const structGCRefNumber = 0
@@ -16,13 +13,8 @@ export const structGCRefNumber = 0
  * @private
  */
 export class GC extends AbstractStruct {
-  /**
+  get deleted () {
-   * @param {ID} id
+    return true
-   * @param {number} length
-   */
-  constructor (id, length) {
-    super(id, length)
-    this.deleted = true
   }
 
   delete () {}
@@ -38,8 +30,13 @@ export class GC extends AbstractStruct {
 
   /**
    * @param {Transaction} transaction
+   * @param {number} offset
    */
-  integrate (transaction) {
+  integrate (transaction, offset) {
+    if (offset > 0) {
+      this.id.clock += offset
+      this.length -= offset
+    }
     addStruct(transaction.doc.store, this)
   }
 
@@ -51,40 +48,13 @@ export class GC extends AbstractStruct {
     encoding.writeUint8(encoder, structGCRefNumber)
     encoding.writeVarUint(encoder, this.length - offset)
   }
-}
-
-/**
- * @private
- */
-export class GCRef extends AbstractStructRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(id)
-    /**
-     * @type {number}
-     */
-    this.length = decoding.readVarUint(decoder)
-  }
 
   /**
    * @param {Transaction} transaction
    * @param {StructStore} store
-   * @param {number} offset
+   * @return {null | number}
-   * @return {GC}
    */
-  toStruct (transaction, store, offset) {
+  getMissing (transaction, store) {
-    if (offset > 0) {
+    return null
-      // @ts-ignore
-      this.id = createID(this.id.client, this.id.clock + offset)
-      this.length -= offset
-    }
-    return new GC(
-      this.id,
-      this.length
-    )
   }
 }

src/structs/Item.js

@@ -1,11 +1,9 @@
 
 import {
   readID,
-  createID,
   writeID,
   GC,
-  nextID,
+  getState,
-  AbstractStructRef,
   AbstractStruct,
   replaceStruct,
   addStruct,
@@ -21,10 +19,11 @@ import {
   readContentAny,
   readContentString,
   readContentEmbed,
+  createID,
   readContentFormat,
   readContentType,
   addChangedTypeToTransaction,
-  ContentType, ContentDeleted, StructStore, ID, AbstractType, Transaction // eslint-disable-line
+  Doc, ContentType, ContentDeleted, StructStore, ID, AbstractType, Transaction // eslint-disable-line
 } from '../internals.js'
 
 import * as error from 'lib0/error.js'
@@ -73,7 +72,7 @@ export const followRedone = (store, id) => {
 export const keepItem = (item, keep) => {
   while (item !== null && item.keep !== keep) {
     item.keep = keep
-    item = item.parent._item
+    item = /** @type {AbstractType<any>} */ (item.parent)._item
   }
 }
 
@@ -88,12 +87,12 @@ export const keepItem = (item, keep) => {
  * @private
  */
 export const splitItem = (transaction, leftItem, diff) => {
-  const id = leftItem.id
   // create rightItem
+  const { client, clock } = leftItem.id
   const rightItem = new Item(
-    createID(id.client, id.clock + diff),
+    createID(client, clock + diff),
     leftItem,
-    createID(id.client, id.clock + diff - 1),
+    createID(client, clock + diff - 1),
     leftItem.right,
     leftItem.rightOrigin,
     leftItem.parent,
@@ -101,7 +100,7 @@ export const splitItem = (transaction, leftItem, diff) => {
     leftItem.content.splice(diff)
   )
   if (leftItem.deleted) {
-    rightItem.deleted = true
+    rightItem.markDeleted()
   }
   if (leftItem.keep) {
     rightItem.keep = true
@@ -116,10 +115,10 @@ export const splitItem = (transaction, leftItem, diff) => {
     rightItem.right.left = rightItem
   }
   // right is more specific.
-  transaction._mergeStructs.add(rightItem.id)
+  transaction._mergeStructs.push(rightItem)
   // update parent._map
   if (rightItem.parentSub !== null && rightItem.right === null) {
-    rightItem.parent._map.set(rightItem.parentSub, rightItem)
+    /** @type {AbstractType<any>} */ (rightItem.parent)._map.set(rightItem.parentSub, rightItem)
   }
   leftItem.length = diff
   return rightItem
@@ -137,10 +136,14 @@ export const splitItem = (transaction, leftItem, diff) => {
  * @private
  */
 export const redoItem = (transaction, item, redoitems) => {
-  if (item.redone !== null) {
+  const doc = transaction.doc
-    return getItemCleanStart(transaction, item.redone)
+  const store = doc.store
+  const ownClientID = doc.clientID
+  const redone = item.redone
+  if (redone !== null) {
+    return getItemCleanStart(transaction, redone)
   }
-  let parentItem = item.parent._item
+  let parentItem = /** @type {AbstractType<any>} */ (item.parent)._item
   /**
    * @type {Item|null}
    */
@@ -158,14 +161,14 @@ export const redoItem = (transaction, item, redoitems) => {
     left = item
     while (left.right !== null) {
       left = left.right
-      if (left.id.client !== transaction.doc.clientID) {
+      if (left.id.client !== ownClientID) {
         // It is not possible to redo this item because it conflicts with a
         // change from another client
         return null
       }
     }
     if (left.right !== null) {
-      left = /** @type {Item} */ (item.parent._map.get(item.parentSub))
+      left = /** @type {Item} */ (/** @type {AbstractType<any>} */ (item.parent)._map.get(item.parentSub))
     }
     right = null
   }
@@ -187,10 +190,10 @@ export const redoItem = (transaction, item, redoitems) => {
        */
       let leftTrace = left
       // trace redone until parent matches
-      while (leftTrace !== null && leftTrace.parent._item !== parentItem) {
+      while (leftTrace !== null && /** @type {AbstractType<any>} */ (leftTrace.parent)._item !== parentItem) {
         leftTrace = leftTrace.redone === null ? null : getItemCleanStart(transaction, leftTrace.redone)
       }
-      if (leftTrace !== null && leftTrace.parent._item === parentItem) {
+      if (leftTrace !== null && /** @type {AbstractType<any>} */ (leftTrace.parent)._item === parentItem) {
         left = leftTrace
         break
       }
@@ -202,27 +205,29 @@ export const redoItem = (transaction, item, redoitems) => {
        */
       let rightTrace = right
       // trace redone until parent matches
-      while (rightTrace !== null && rightTrace.parent._item !== parentItem) {
+      while (rightTrace !== null && /** @type {AbstractType<any>} */ (rightTrace.parent)._item !== parentItem) {
         rightTrace = rightTrace.redone === null ? null : getItemCleanStart(transaction, rightTrace.redone)
       }
-      if (rightTrace !== null && rightTrace.parent._item === parentItem) {
+      if (rightTrace !== null && /** @type {AbstractType<any>} */ (rightTrace.parent)._item === parentItem) {
         right = rightTrace
         break
       }
       right = right.right
     }
   }
+  const nextClock = getState(store, ownClientID)
+  const nextId = createID(ownClientID, nextClock)
   const redoneItem = new Item(
-    nextID(transaction),
+    nextId,
-    left, left === null ? null : left.lastId,
+    left, left && left.lastId,
-    right, right === null ? null : right.id,
+    right, right && right.id,
     parentItem === null ? item.parent : /** @type {ContentType} */ (parentItem.content).type,
     item.parentSub,
     item.content.copy()
   )
-  item.redone = redoneItem.id
+  item.redone = nextId
   keepItem(redoneItem, true)
-  redoneItem.integrate(transaction)
+  redoneItem.integrate(transaction, 0)
   return redoneItem
 }
 
@@ -236,7 +241,7 @@ export class Item extends AbstractStruct {
    * @param {ID | null} origin
    * @param {Item | null} right
    * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
+   * @param {AbstractType<any>|ID|null} parent Is a type if integrated, is null if it is possible to copy parent from left or right, is ID before integration to search for it.
    * @param {string | null} parentSub
    * @param {AbstractContent} content
    */
@@ -245,7 +250,6 @@ export class Item extends AbstractStruct {
     /**
      * The item that was originally to the left of this item.
      * @type {ID | null}
-     * @readonly
      */
     this.origin = origin
     /**
@@ -260,14 +264,11 @@ export class Item extends AbstractStruct {
     this.right = right
     /**
      * The item that was originally to the right of this item.
-     * @readonly
      * @type {ID | null}
      */
     this.rightOrigin = rightOrigin
     /**
-     * The parent type.
+     * @type {AbstractType<any>|ID|null}
-     * @type {AbstractType<any>}
-     * @readonly
      */
     this.parent = parent
     /**
@@ -276,14 +277,8 @@ export class Item extends AbstractStruct {
      * to insert this item. If `parentSub = null` type._start is the list in
      * which to insert to. Otherwise it is `parent._map`.
      * @type {String | null}
-     * @readonly
      */
     this.parentSub = parentSub
-    /**
-     * Whether this item was deleted or not.
-     * @type {Boolean}
-     */
-    this.deleted = false
     /**
      * If this type's effect is reundone this type refers to the type that undid
      * this operation.
@@ -294,40 +289,130 @@ export class Item extends AbstractStruct {
      * @type {AbstractContent}
      */
     this.content = content
-    this.length = content.getLength()
+    this.info = this.content.isCountable() ? binary.BIT2 : 0
-    this.countable = content.isCountable()
+  }
+
   /**
    * If true, do not garbage collect this Item.
    */
-    this.keep = false
+  get keep () {
+    return (this.info & binary.BIT1) > 0
+  }
+
+  set keep (doKeep) {
+    if (this.keep !== doKeep) {
+      this.info ^= binary.BIT1
+    }
+  }
+
+  get countable () {
+    return (this.info & binary.BIT2) > 0
+  }
+
+  /**
+   * Whether this item was deleted or not.
+   * @type {Boolean}
+   */
+  get deleted () {
+    return (this.info & binary.BIT3) > 0
+  }
+
+  set deleted (doDelete) {
+    if (this.deleted !== doDelete) {
+      this.info ^= binary.BIT3
+    }
+  }
+
+  markDeleted () {
+    this.info |= binary.BIT3
+  }
+
+  /**
+   * Return the creator clientID of the missing op or define missing items and return null.
+   *
+   * @param {Transaction} transaction
+   * @param {StructStore} store
+   * @return {null | number}
+   */
+  getMissing (transaction, store) {
+    if (this.origin && this.origin.client !== this.id.client && this.origin.clock >= getState(store, this.origin.client)) {
+      return this.origin.client
+    }
+    if (this.rightOrigin && this.rightOrigin.client !== this.id.client && this.rightOrigin.clock >= getState(store, this.rightOrigin.client)) {
+      return this.rightOrigin.client
+    }
+    if (this.parent && this.parent.constructor === ID && this.id.client !== this.parent.client && this.parent.clock >= getState(store, this.parent.client)) {
+      return this.parent.client
+    }
+
+    // We have all missing ids, now find the items
+
+    if (this.origin) {
+      this.left = getItemCleanEnd(transaction, store, this.origin)
+      this.origin = this.left.lastId
+    }
+    if (this.rightOrigin) {
+      this.right = getItemCleanStart(transaction, this.rightOrigin)
+      this.rightOrigin = this.right.id
+    }
+    // only set parent if this shouldn't be garbage collected
+    if (!this.parent) {
+      if (this.left && this.left.constructor === Item) {
+        this.parent = this.left.parent
+        this.parentSub = this.left.parentSub
+      }
+      if (this.right && this.right.constructor === Item) {
+        this.parent = this.right.parent
+        this.parentSub = this.right.parentSub
+      }
+    } else if (this.parent.constructor === ID) {
+      const parentItem = getItem(store, this.parent)
+      if (parentItem.constructor === GC) {
+        this.parent = null
+      } else {
+        this.parent = /** @type {ContentType} */ (parentItem.content).type
+      }
+    }
+    return null
   }
 
   /**
    * @param {Transaction} transaction
-   * @private
+   * @param {number} offset
    */
-  integrate (transaction) {
+  integrate (transaction, offset) {
-    const store = transaction.doc.store
+    if (offset > 0) {
-    const id = this.id
+      this.id.clock += offset
-    const parent = this.parent
+      this.left = getItemCleanEnd(transaction, transaction.doc.store, createID(this.id.client, this.id.clock - 1))
-    const parentSub = this.parentSub
+      this.origin = this.left.lastId
-    const length = this.length
+      this.content = this.content.splice(offset)
+      this.length -= offset
+    }
+
+    if (this.parent) {
+      if ((!this.left && (!this.right || this.right.left !== null)) || (this.left && this.left.right !== this.right)) {
+        /**
+         * @type {Item|null}
+         */
+        let left = this.left
+
         /**
          * @type {Item|null}
          */
         let o
         // set o to the first conflicting item
-    if (this.left !== null) {
+        if (left !== null) {
-      o = this.left.right
+          o = left.right
-    } else if (parentSub !== null) {
+        } else if (this.parentSub !== null) {
-      o = parent._map.get(parentSub) || null
+          o = /** @type {AbstractType<any>} */ (this.parent)._map.get(this.parentSub) || null
           while (o !== null && o.left !== null) {
             o = o.left
           }
         } else {
-      o = parent._start
+          o = /** @type {AbstractType<any>} */ (this.parent)._start
         }
         // TODO: use something like DeleteSet here (a tree implementation would be best)
+        // @todo use global set definitions
         /**
          * @type {Set<Item>}
          */
@@ -344,14 +429,14 @@ export class Item extends AbstractStruct {
           conflictingItems.add(o)
           if (compareIDs(this.origin, o.origin)) {
             // case 1
-        if (o.id.client < id.client) {
+            if (o.id.client < this.id.client) {
-          this.left = o
+              left = o
               conflictingItems.clear()
             }
-      } else if (o.origin !== null && itemsBeforeOrigin.has(getItem(store, o.origin))) {
+          } else if (o.origin !== null && itemsBeforeOrigin.has(getItem(transaction.doc.store, o.origin))) {
             // case 2
-        if (o.origin === null || !conflictingItems.has(getItem(store, o.origin))) {
+            if (o.origin === null || !conflictingItems.has(getItem(transaction.doc.store, o.origin))) {
-          this.left = o
+              left = o
               conflictingItems.clear()
             }
           } else {
@@ -359,6 +444,8 @@ export class Item extends AbstractStruct {
           }
           o = o.right
         }
+        this.left = left
+      }
       // reconnect left/right + update parent map/start if necessary
       if (this.left !== null) {
         const right = this.left.right
@@ -366,44 +453,47 @@ export class Item extends AbstractStruct {
         this.left.right = this
       } else {
         let r
-      if (parentSub !== null) {
+        if (this.parentSub !== null) {
-        r = parent._map.get(parentSub) || null
+          r = /** @type {AbstractType<any>} */ (this.parent)._map.get(this.parentSub) || null
           while (r !== null && r.left !== null) {
             r = r.left
           }
         } else {
-        r = parent._start
+          r = /** @type {AbstractType<any>} */ (this.parent)._start
-        parent._start = this
+          ;/** @type {AbstractType<any>} */ (this.parent)._start = this
         }
         this.right = r
       }
       if (this.right !== null) {
         this.right.left = this
-    } else if (parentSub !== null) {
+      } else if (this.parentSub !== null) {
         // set as current parent value if right === null and this is parentSub
-      parent._map.set(parentSub, this)
+        /** @type {AbstractType<any>} */ (this.parent)._map.set(this.parentSub, this)
         if (this.left !== null) {
           // this is the current attribute value of parent. delete right
           this.left.delete(transaction)
         }
       }
       // adjust length of parent
-    if (parentSub === null && this.countable && !this.deleted) {
+      if (this.parentSub === null && this.countable && !this.deleted) {
-      parent._length += length
+        /** @type {AbstractType<any>} */ (this.parent)._length += this.length
       }
-    addStruct(store, this)
+      addStruct(transaction.doc.store, this)
       this.content.integrate(transaction, this)
       // add parent to transaction.changed
-    addChangedTypeToTransaction(transaction, parent, parentSub)
+      addChangedTypeToTransaction(transaction, /** @type {AbstractType<any>} */ (this.parent), this.parentSub)
-    if ((parent._item !== null && parent._item.deleted) || (this.right !== null && parentSub !== null)) {
+      if ((/** @type {AbstractType<any>} */ (this.parent)._item !== null && /** @type {AbstractType<any>} */ (this.parent)._item.deleted) || (this.right !== null && this.parentSub !== null)) {
         // delete if parent is deleted or if this is not the current attribute value of parent
         this.delete(transaction)
       }
+    } else {
+      // parent is not defined. Integrate GC struct instead
+      new GC(this.id, this.length).integrate(transaction, 0)
+    }
   }
 
   /**
    * Returns the next non-deleted item
-   * @private
    */
   get next () {
     let n = this.right
@@ -415,7 +505,6 @@ export class Item extends AbstractStruct {
 
   /**
    * Returns the previous non-deleted item
-   * @private
    */
   get prev () {
     let n = this.left
@@ -429,7 +518,8 @@ export class Item extends AbstractStruct {
    * Computes the last content address of this Item.
    */
   get lastId () {
-    return createID(this.id.client, this.id.clock + this.length - 1)
+    // allocating ids is pretty costly because of the amount of ids created, so we try to reuse whenever possible
+    return this.length === 1 ? this.id : createID(this.id.client, this.id.clock + this.length - 1)
   }
 
   /**
@@ -471,12 +561,12 @@ export class Item extends AbstractStruct {
    */
   delete (transaction) {
     if (!this.deleted) {
-      const parent = this.parent
+      const parent = /** @type {AbstractType<any>} */ (this.parent)
       // adjust the length of parent
       if (this.countable && this.parentSub === null) {
         parent._length -= this.length
       }
-      this.deleted = true
+      this.markDeleted()
       addToDeleteSet(transaction.deleteSet, this.id, this.length)
       maplib.setIfUndefined(transaction.changed, parent, set.create).add(this.parentSub)
       this.content.delete(transaction)
@@ -486,8 +576,6 @@ export class Item extends AbstractStruct {
   /**
    * @param {StructStore} store
    * @param {boolean} parentGCd
-   *
-   * @private
    */
   gc (store, parentGCd) {
     if (!this.deleted) {
@@ -509,8 +597,6 @@ export class Item extends AbstractStruct {
    *
    * @param {encoding.Encoder} encoder The encoder to write data to.
    * @param {number} offset
-   *
-   * @private
    */
   write (encoder, offset) {
     const origin = offset > 0 ? createID(this.id.client, this.id.clock + offset - 1) : this.origin
@@ -528,8 +614,9 @@ export class Item extends AbstractStruct {
       writeID(encoder, rightOrigin)
     }
     if (origin === null && rightOrigin === null) {
-      const parent = this.parent
+      const parent = /** @type {AbstractType<any>} */ (this.parent)
-      if (parent._item === null) {
+      const parentItem = parent._item
+      if (parentItem === null) {
         // parent type on y._map
         // find the correct key
         const ykey = findRootTypeKey(parent)
@@ -537,7 +624,7 @@ export class Item extends AbstractStruct {
         encoding.writeVarString(encoder, ykey)
       } else {
         encoding.writeVarUint(encoder, 0) // write parent id
-        writeID(encoder, parent._item.id)
+        writeID(encoder, parentItem.id)
       }
       if (parentSub !== null) {
         encoding.writeVarString(encoder, parentSub)
@@ -663,26 +750,22 @@ export class AbstractContent {
 }
 
 /**
- * @private
- */
-export class ItemRef extends AbstractStructRef {
-  /**
  * @param {decoding.Decoder} decoder
  * @param {ID} id
  * @param {number} info
+ * @param {Doc} doc
  */
-  constructor (decoder, id, info) {
+export const readItem = (decoder, id, info, doc) => {
-    super(id)
   /**
    * The item that was originally to the left of this item.
    * @type {ID | null}
    */
-    this.left = (info & binary.BIT8) === binary.BIT8 ? readID(decoder) : null
+  const origin = (info & binary.BIT8) === binary.BIT8 ? readID(decoder) : null
   /**
    * The item that was originally to the right of this item.
    * @type {ID | null}
    */
-    this.right = (info & binary.BIT7) === binary.BIT7 ? readID(decoder) : null
+  const rightOrigin = (info & binary.BIT7) === binary.BIT7 ? readID(decoder) : null
   const canCopyParentInfo = (info & (binary.BIT7 | binary.BIT8)) === 0
   const hasParentYKey = canCopyParentInfo ? decoding.readVarUint(decoder) === 1 : false
   /**
@@ -691,95 +774,12 @@ export class ItemRef extends AbstractStructRef {
    * It indicates how we store/retrieve parent from `y.share`
    * @type {string|null}
    */
-    this.parentYKey = canCopyParentInfo && hasParentYKey ? decoding.readVarString(decoder) : null
+  const parentYKey = canCopyParentInfo && hasParentYKey ? decoding.readVarString(decoder) : null
-    /**
-     * The parent type.
-     * @type {ID | null}
-     */
-    this.parent = canCopyParentInfo && !hasParentYKey ? readID(decoder) : null
-    /**
-     * If the parent refers to this item with some kind of key (e.g. YMap, the
-     * key is specified here. The key is then used to refer to the list in which
-     * to insert this item. If `parentSub = null` type._start is the list in
-     * which to insert to. Otherwise it is `parent._map`.
-     * @type {String | null}
-     */
-    this.parentSub = canCopyParentInfo && (info & binary.BIT6) === binary.BIT6 ? decoding.readVarString(decoder) : null
-    const missing = this._missing
-    if (this.left !== null) {
-      missing.push(this.left)
-    }
-    if (this.right !== null) {
-      missing.push(this.right)
-    }
-    if (this.parent !== null) {
-      missing.push(this.parent)
-    }
-    /**
-     * @type {AbstractContent}
-     */
-    this.content = readItemContent(decoder, info)
-    this.length = this.content.getLength()
-  }
 
-  /**
+  return new Item(
-   * @param {Transaction} transaction
+    id, null, origin, null, rightOrigin,
-   * @param {StructStore} store
+    canCopyParentInfo && !hasParentYKey ? readID(decoder) : (parentYKey ? doc.get(parentYKey) : null), // parent
-   * @param {number} offset
+    canCopyParentInfo && (info & binary.BIT6) === binary.BIT6 ? decoding.readVarString(decoder) : null, // parentSub
-   * @return {Item|GC}
+    /** @type {AbstractContent} */ (readItemContent(decoder, info)) // item content
-   */
-  toStruct (transaction, store, offset) {
-    if (offset > 0) {
-      /**
-       * @type {ID}
-       */
-      const id = this.id
-      this.id = createID(id.client, id.clock + offset)
-      this.left = createID(this.id.client, this.id.clock - 1)
-      this.content = this.content.splice(offset)
-      this.length -= offset
-    }
-
-    const left = this.left === null ? null : getItemCleanEnd(transaction, store, this.left)
-    const right = this.right === null ? null : getItemCleanStart(transaction, this.right)
-    let parent = null
-    let parentSub = this.parentSub
-    if (this.parent !== null) {
-      const parentItem = getItem(store, this.parent)
-      // Edge case: toStruct is called with an offset > 0. In this case left is defined.
-      // Depending in which order structs arrive, left may be GC'd and the parent not
-      // deleted. This is why we check if left is GC'd. Strictly we don't have
-      // to check if right is GC'd, but we will in case we run into future issues
-      if (!parentItem.deleted && (left === null || left.constructor !== GC) && (right === null || right.constructor !== GC)) {
-        parent = /** @type {ContentType} */ (parentItem.content).type
-      }
-    } else if (this.parentYKey !== null) {
-      parent = transaction.doc.get(this.parentYKey)
-    } else if (left !== null) {
-      if (left.constructor !== GC) {
-        parent = left.parent
-        parentSub = left.parentSub
-      }
-    } else if (right !== null) {
-      if (right.constructor !== GC) {
-        parent = right.parent
-        parentSub = right.parentSub
-      }
-    } else {
-      throw error.unexpectedCase()
-    }
-
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new Item(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.content
   )
-  }
 }

src/types/AbstractType.js

@@ -4,14 +4,14 @@ import {
   callEventHandlerListeners,
   addEventHandlerListener,
   createEventHandler,
-  nextID,
+  getState,
   isVisible,
   ContentType,
+  createID,
   ContentAny,
   ContentBinary,
-  createID,
   getItemCleanStart,
-  Doc, Snapshot, Transaction, EventHandler, YEvent, Item, // eslint-disable-line
+  ID, Doc, Snapshot, Transaction, EventHandler, YEvent, Item, // eslint-disable-line
 } from '../internals.js'
 
 import * as map from 'lib0/map.js'
@@ -19,10 +19,25 @@ import * as iterator from 'lib0/iterator.js'
 import * as error from 'lib0/error.js'
 import * as encoding from 'lib0/encoding.js' // eslint-disable-line
 
+/**
+ * Accumulate all (list) children of a type and return them as an Array.
+ *
+ * @param {AbstractType<any>} t
+ * @return {Array<Item>}
+ */
+export const getTypeChildren = t => {
+  let s = t._start
+  const arr = []
+  while (s) {
+    arr.push(s)
+    s = s.right
+  }
+  return arr
+}
+
 /**
  * Call event listeners with an event. This will also add an event to all
  * parents (for `.observeDeep` handlers).
- * @private
  *
  * @template EventType
  * @param {AbstractType<EventType>} type
@@ -38,7 +53,7 @@ export const callTypeObservers = (type, transaction, event) => {
     if (type._item === null) {
       break
     }
-    type = type._item.parent
+    type = /** @type {AbstractType<any>} */ (type._item.parent)
   }
   callEventHandlerListeners(changedType._eH, event, transaction)
 }
@@ -54,17 +69,14 @@ export class AbstractType {
      */
     this._item = null
     /**
-     * @private
      * @type {Map<string,Item>}
      */
     this._map = new Map()
     /**
-     * @private
      * @type {Item|null}
      */
     this._start = null
     /**
-     * @private
      * @type {Doc|null}
      */
     this.doc = null
@@ -90,7 +102,6 @@ export class AbstractType {
    *
    * @param {Doc} y The Yjs instance
    * @param {Item|null} item
-   * @private
    */
   _integrate (y, item) {
     this.doc = y
@@ -99,7 +110,6 @@ export class AbstractType {
 
   /**
    * @return {AbstractType<EventType>}
-   * @private
    */
   _copy () {
     throw error.methodUnimplemented()
@@ -107,7 +117,6 @@ export class AbstractType {
 
   /**
    * @param {encoding.Encoder} encoder
-   * @private
    */
   _write (encoder) { }
 
@@ -128,8 +137,6 @@ export class AbstractType {
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
-   *
-   * @private
    */
   _callObserver (transaction, parentSubs) { /* skip if no type is specified */ }
 
@@ -368,6 +375,9 @@ export const typeListGet = (type, index) => {
  */
 export const typeListInsertGenericsAfter = (transaction, parent, referenceItem, content) => {
   let left = referenceItem
+  const doc = transaction.doc
+  const ownClientId = doc.clientID
+  const store = doc.store
   const right = referenceItem === null ? parent._start : referenceItem.right
   /**
    * @type {Array<Object|Array<any>|number>}
@@ -375,8 +385,8 @@ export const typeListInsertGenericsAfter = (transaction, parent, referenceItem,
   let jsonContent = []
   const packJsonContent = () => {
     if (jsonContent.length > 0) {
-      left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentAny(jsonContent))
+      left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentAny(jsonContent))
-      left.integrate(transaction)
+      left.integrate(transaction, 0)
       jsonContent = []
     }
   }
@@ -394,13 +404,13 @@ export const typeListInsertGenericsAfter = (transaction, parent, referenceItem,
         switch (c.constructor) {
           case Uint8Array:
           case ArrayBuffer:
-            left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentBinary(new Uint8Array(/** @type {Uint8Array} */ (c))))
+            left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentBinary(new Uint8Array(/** @type {Uint8Array} */ (c))))
-            left.integrate(transaction)
+            left.integrate(transaction, 0)
             break
           default:
             if (c instanceof AbstractType) {
-              left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentType(c))
+              left = new Item(createID(ownClientId, getState(store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentType(c))
-              left.integrate(transaction)
+              left.integrate(transaction, 0)
             } else {
               throw new Error('Unexpected content type in insert operation')
             }
@@ -502,6 +512,8 @@ export const typeMapDelete = (transaction, parent, key) => {
  */
 export const typeMapSet = (transaction, parent, key, value) => {
   const left = parent._map.get(key) || null
+  const doc = transaction.doc
+  const ownClientId = doc.clientID
   let content
   if (value == null) {
     content = new ContentAny([value])
@@ -525,7 +537,7 @@ export const typeMapSet = (transaction, parent, key, value) => {
         }
     }
   }
-  new Item(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, content).integrate(transaction)
+  new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, null, null, parent, key, content).integrate(transaction, 0)
 }
 
 /**

src/types/YArray.js

@@ -40,7 +40,7 @@ export class YArrayEvent extends YEvent {
  * A shared Array implementation.
  * @template T
  * @extends AbstractType<YArrayEvent<T>>
- * @implements {IterableIterator<T>}
+ * @implements {Iterable<T>}
  */
 export class YArray extends AbstractType {
   constructor () {
@@ -61,8 +61,6 @@ export class YArray extends AbstractType {
    *
    * @param {Doc} y The Yjs instance
    * @param {Item} item
-   *
-   * @private
    */
   _integrate (y, item) {
     super._integrate(y, item)
@@ -83,8 +81,6 @@ export class YArray extends AbstractType {
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
-   *
-   * @private
    */
   _callObserver (transaction, parentSubs) {
     callTypeObservers(this, transaction, new YArrayEvent(this, transaction))
@@ -125,6 +121,15 @@ export class YArray extends AbstractType {
     this.insert(this.length, content)
   }
 
+  /**
+   * Preppends content to this YArray.
+   *
+   * @param {Array<T>} content Array of content to preppend.
+   */
+  unshift (content) {
+    this.insert(0, content)
+  }
+
   /**
    * Deletes elements starting from an index.
    *
@@ -200,7 +205,6 @@ export class YArray extends AbstractType {
 
   /**
    * @param {encoding.Encoder} encoder
-   * @private
    */
   _write (encoder) {
     encoding.writeVarUint(encoder, YArrayRefID)

src/types/YMap.js

@@ -42,16 +42,26 @@ export class YMapEvent extends YEvent {
  * A shared Map implementation.
  *
  * @extends AbstractType<YMapEvent<T>>
- * @implements {IterableIterator}
+ * @implements {Iterable<T>}
  */
 export class YMap extends AbstractType {
-  constructor () {
+  /**
+   *
+   * @param {Iterable<readonly [string, any]>=} entries - an optional iterable to initialize the YMap
+   */
+  constructor (entries) {
     super()
     /**
      * @type {Map<string,any>?}
      * @private
      */
+    this._prelimContent = null
+
+    if (entries === undefined) {
       this._prelimContent = new Map()
+    } else {
+      this._prelimContent = new Map(entries)
+    }
   }
 
   /**
@@ -63,8 +73,6 @@ export class YMap extends AbstractType {
    *
    * @param {Doc} y The Yjs instance
    * @param {Item} item
-   *
-   * @private
    */
   _integrate (y, item) {
     super._integrate(y, item)
@@ -83,8 +91,6 @@ export class YMap extends AbstractType {
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
-   *
-   * @private
    */
   _callObserver (transaction, parentSubs) {
     callTypeObservers(this, transaction, new YMapEvent(this, transaction, parentSubs))
@@ -109,6 +115,15 @@ export class YMap extends AbstractType {
     return map
   }
 
+  /**
+   * Returns the size of the YMap (count of key/value pairs)
+   *
+   * @return {number}
+   */
+  get size () {
+    return [...createMapIterator(this._map)].length
+  }
+
   /**
    * Returns the keys for each element in the YMap Type.
    *
@@ -137,7 +152,7 @@ export class YMap extends AbstractType {
   }
 
   /**
-   * Executes a provided function on once on overy key-value pair.
+   * Executes a provided function on once on every key-value pair.
    *
    * @param {function(T,string,YMap<T>):void} f A function to execute on every element of this YArray.
    */
@@ -215,8 +230,6 @@ export class YMap extends AbstractType {
 
   /**
    * @param {encoding.Encoder} encoder
-   *
-   * @private
    */
   _write (encoder) {
     encoding.writeVarUint(encoder, YMapRefID)

src/types/YText.js

@@ -6,23 +6,27 @@
 import {
   YEvent,
   AbstractType,
-  nextID,
-  createID,
   getItemCleanStart,
+  getState,
   isVisible,
+  createID,
   YTextRefID,
   callTypeObservers,
   transact,
   ContentEmbed,
+  GC,
   ContentFormat,
   ContentString,
   splitSnapshotAffectedStructs,
+  iterateDeletedStructs,
+  iterateStructs,
   ID, Doc, Item, Snapshot, Transaction // eslint-disable-line
 } from '../internals.js'
 
 import * as decoding from 'lib0/decoding.js' // eslint-disable-line
 import * as encoding from 'lib0/encoding.js'
 import * as object from 'lib0/object.js'
+import * as map from 'lib0/map.js'
 
 /**
  * @param {any} a
@@ -122,15 +126,14 @@ const findPosition = (transaction, parent, index) => {
  *
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {Item|null} left
+ * @param {ItemListPosition} currPos
- * @param {Item|null} right
  * @param {Map<string,any>} negatedAttributes
- * @return {ItemListPosition}
  *
  * @private
  * @function
  */
-const insertNegatedAttributes = (transaction, parent, left, right, negatedAttributes) => {
+const insertNegatedAttributes = (transaction, parent, currPos, negatedAttributes) => {
+  let { left, right } = currPos
   // check if we really need to remove attributes
   while (
     right !== null && (
@@ -146,11 +149,14 @@ const insertNegatedAttributes = (transaction, parent, left, right, negatedAttrib
     left = right
     right = right.right
   }
+  const doc = transaction.doc
+  const ownClientId = doc.clientID
   for (const [key, val] of negatedAttributes) {
-    left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentFormat(key, val))
+    left = 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)
+    left.integrate(transaction, 0)
   }
-  return { left, right }
+  currPos.left = left
+  currPos.right = right
 }
 
 /**
@@ -170,17 +176,16 @@ const updateCurrentAttributes = (currentAttributes, format) => {
 }
 
 /**
- * @param {Item|null} left
+ * @param {ItemListPosition} currPos
- * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {Object<string,any>} attributes
- * @return {ItemListPosition}
  *
  * @private
  * @function
  */
-const minimizeAttributeChanges = (left, right, currentAttributes, attributes) => {
+const minimizeAttributeChanges = (currPos, currentAttributes, attributes) => {
   // go right while attributes[right.key] === right.value (or right is deleted)
+  let { left, right } = currPos
   while (true) {
     if (right === null) {
       break
@@ -195,22 +200,24 @@ const minimizeAttributeChanges = (left, right, currentAttributes, attributes) =>
     left = right
     right = right.right
   }
-  return new ItemListPosition(left, right)
+  currPos.left = left
+  currPos.right = right
 }
 
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {Item|null} left
+ * @param {ItemListPosition} currPos
- * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {Object<string,any>} attributes
- * @return {ItemInsertionResult}
+ * @return {Map<string,any>}
  *
  * @private
  * @function
  **/
-const insertAttributes = (transaction, parent, left, right, currentAttributes, attributes) => {
+const insertAttributes = (transaction, parent, currPos, currentAttributes, attributes) => {
+  const doc = transaction.doc
+  const ownClientId = doc.clientID
   const negatedAttributes = new Map()
   // insert format-start items
   for (const key in attributes) {
@@ -219,62 +226,60 @@ const insertAttributes = (transaction, parent, left, right, currentAttributes, a
     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))
+      const { left, right } = currPos
-      left.integrate(transaction)
+      currPos.left = new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentFormat(key, val))
+      currPos.left.integrate(transaction, 0)
     }
   }
-  return new ItemInsertionResult(left, right, negatedAttributes)
+  return negatedAttributes
 }
 
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {Item|null} left
+ * @param {ItemListPosition} currPos
- * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {string|object} text
  * @param {Object<string,any>} attributes
- * @return {ItemListPosition}
  *
  * @private
  * @function
  **/
-const insertText = (transaction, parent, left, right, currentAttributes, text, attributes) => {
+const insertText = (transaction, parent, currPos, currentAttributes, text, attributes) => {
   for (const [key] of currentAttributes) {
     if (attributes[key] === undefined) {
       attributes[key] = null
     }
   }
-  const minPos = minimizeAttributeChanges(left, right, currentAttributes, attributes)
+  const doc = transaction.doc
-  const insertPos = insertAttributes(transaction, parent, minPos.left, minPos.right, currentAttributes, attributes)
+  const ownClientId = doc.clientID
-  left = insertPos.left
+  minimizeAttributeChanges(currPos, currentAttributes, attributes)
-  right = insertPos.right
+  const negatedAttributes = insertAttributes(transaction, parent, currPos, currentAttributes, attributes)
   // insert content
-  const content = text.constructor === String ? new ContentString(text) : new ContentEmbed(text)
+  const content = text.constructor === String ? new ContentString(/** @type {string} */ (text)) : new ContentEmbed(text)
-  left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, content)
+  const { left, right } = currPos
-  left.integrate(transaction)
+  currPos.left = new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, content)
-  return insertNegatedAttributes(transaction, parent, left, insertPos.right, insertPos.negatedAttributes)
+  currPos.left.integrate(transaction, 0)
+  return insertNegatedAttributes(transaction, parent, currPos, negatedAttributes)
 }
 
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {Item|null} left
+ * @param {ItemListPosition} currPos
- * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {number} length
  * @param {Object<string,any>} attributes
- * @return {ItemListPosition}
  *
  * @private
  * @function
  */
-const formatText = (transaction, parent, left, right, currentAttributes, length, attributes) => {
+const formatText = (transaction, parent, currPos, currentAttributes, length, attributes) => {
-  const minPos = minimizeAttributeChanges(left, right, currentAttributes, attributes)
+  const doc = transaction.doc
-  const insertPos = insertAttributes(transaction, parent, minPos.left, minPos.right, currentAttributes, attributes)
+  const ownClientId = doc.clientID
-  const negatedAttributes = insertPos.negatedAttributes
+  minimizeAttributeChanges(currPos, currentAttributes, attributes)
-  left = insertPos.left
+  const negatedAttributes = insertAttributes(transaction, parent, currPos, currentAttributes, attributes)
-  right = insertPos.right
+  let { left, right } = currPos
   // iterate until first non-format or null is found
   // delete all formats with attributes[format.key] != null
   while (length > 0 && right !== null) {
@@ -314,16 +319,121 @@ const formatText = (transaction, parent, left, right, currentAttributes, length,
     for (; length > 0; length--) {
       newlines += '\n'
     }
-    left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentString(newlines))
+    left = new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, new ContentString(newlines))
-    left.integrate(transaction)
+    left.integrate(transaction, 0)
   }
-  return insertNegatedAttributes(transaction, parent, left, right, negatedAttributes)
+  currPos.left = left
+  currPos.right = right
+  insertNegatedAttributes(transaction, parent, currPos, negatedAttributes)
+}
+
+/**
+ * Call this function after string content has been deleted in order to
+ * clean up formatting Items.
+ *
+ * @param {Transaction} transaction
+ * @param {Item} start
+ * @param {Item|null} end exclusive end, automatically iterates to the next Content Item
+ * @param {Map<string,any>} startAttributes
+ * @param {Map<string,any>} endAttributes This attribute is modified!
+ * @return {number} The amount of formatting Items deleted.
+ *
+ * @function
+ */
+const cleanupFormattingGap = (transaction, start, end, startAttributes, endAttributes) => {
+  while (end && end.content.constructor !== ContentString && end.content.constructor !== ContentEmbed) {
+    if (!end.deleted && end.content.constructor === ContentFormat) {
+      updateCurrentAttributes(endAttributes, /** @type {ContentFormat} */ (end.content))
+    }
+    end = end.right
+  }
+  let cleanups = 0
+  while (start !== end) {
+    if (!start.deleted) {
+      const content = start.content
+      switch (content.constructor) {
+        case ContentFormat: {
+          const { key, value } = /** @type {ContentFormat} */ (content)
+          if ((endAttributes.get(key) || null) !== value || (startAttributes.get(key) || null) === value) {
+            // Either this format is overwritten or it is not necessary because the attribute already existed.
+            start.delete(transaction)
+            cleanups++
+          }
+          break
+        }
+      }
+    }
+    start = /** @type {Item} */ (start.right)
+  }
+  return cleanups
 }
 
 /**
  * @param {Transaction} transaction
- * @param {Item|null} left
+ * @param {Item | null} item
- * @param {Item|null} right
+ */
+const cleanupContextlessFormattingGap = (transaction, item) => {
+  // iterate until item.right is null or content
+  while (item && item.right && (item.right.deleted || (item.right.content.constructor !== ContentString && item.right.content.constructor !== ContentEmbed))) {
+    item = item.right
+  }
+  const attrs = new Set()
+  // iterate back until a content item is found
+  while (item && (item.deleted || (item.content.constructor !== ContentString && item.content.constructor !== ContentEmbed))) {
+    if (!item.deleted && item.content.constructor === ContentFormat) {
+      const key = /** @type {ContentFormat} */ (item.content).key
+      if (attrs.has(key)) {
+        item.delete(transaction)
+      } else {
+        attrs.add(key)
+      }
+    }
+    item = item.left
+  }
+}
+
+/**
+ * This function is experimental and subject to change / be removed.
+ *
+ * Ideally, we don't need this function at all. Formatting attributes should be cleaned up
+ * automatically after each change. This function iterates twice over the complete YText type
+ * and removes unnecessary formatting attributes. This is also helpful for testing.
+ *
+ * This function won't be exported anymore as soon as there is confidence that the YText type works as intended.
+ *
+ * @param {YText} type
+ * @return {number} How many formatting attributes have been cleaned up.
+ */
+export const cleanupYTextFormatting = type => {
+  let res = 0
+  transact(/** @type {Doc} */ (type.doc), transaction => {
+    let start = /** @type {Item} */ (type._start)
+    let end = type._start
+    let startAttributes = map.create()
+    const currentAttributes = map.copy(startAttributes)
+    while (end) {
+      if (end.deleted === false) {
+        switch (end.content.constructor) {
+          case ContentFormat:
+            updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (end.content))
+            break
+          case ContentEmbed:
+          case ContentString:
+            res += cleanupFormattingGap(transaction, start, end, startAttributes, currentAttributes)
+            startAttributes = map.copy(currentAttributes)
+            start = end
+            break
+        }
+      }
+      end = end.right
+    }
+  })
+  return res
+}
+
+/**
+ * @param {Transaction} transaction
+ * @param {ItemListPosition} currPos
  * @param {Map<string,any>} currentAttributes
  * @param {number} length
  * @return {ItemListPosition}
@@ -331,7 +441,10 @@ const formatText = (transaction, parent, left, right, currentAttributes, length,
  * @private
  * @function
  */
-const deleteText = (transaction, left, right, currentAttributes, length) => {
+const deleteText = (transaction, currPos, currentAttributes, length) => {
+  const startAttrs = map.copy(currentAttributes)
+  const start = currPos.right
+  let { left, right } = currPos
   while (length > 0 && right !== null) {
     if (right.deleted === false) {
       switch (right.content.constructor) {
@@ -351,7 +464,12 @@ const deleteText = (transaction, left, right, currentAttributes, length) => {
     left = right
     right = right.right
   }
-  return { left, right }
+  if (start) {
+    cleanupFormattingGap(transaction, start, right, startAttrs, map.copy(currentAttributes))
+  }
+  currPos.left = left
+  currPos.right = right
+  return currPos
 }
 
 /**
@@ -400,7 +518,6 @@ export class YTextEvent extends YEvent {
   constructor (ytext, transaction) {
     super(ytext, transaction)
     /**
-     * @private
      * @type {Array<DeltaItem>|null}
      */
     this._delta = null
@@ -612,7 +729,6 @@ export class YText extends AbstractType {
     /**
      * Array of pending operations on this type
      * @type {Array<function():void>?}
-     * @private
      */
     this._pending = string !== undefined ? [() => this.insert(0, string)] : []
   }
@@ -629,8 +745,6 @@ export class YText extends AbstractType {
   /**
    * @param {Doc} y
    * @param {Item} item
-   *
-   * @private
    */
   _integrate (y, item) {
     super._integrate(y, item)
@@ -651,11 +765,50 @@ export class YText extends AbstractType {
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
-   *
-   * @private
    */
   _callObserver (transaction, parentSubs) {
-    callTypeObservers(this, transaction, new YTextEvent(this, transaction))
+    const event = new YTextEvent(this, transaction)
+    const doc = transaction.doc
+    // If a remote change happened, we try to cleanup potential formatting duplicates.
+    if (!transaction.local) {
+      // check if another formatting item was inserted
+      let foundFormattingItem = false
+      for (const [client, afterClock] of transaction.afterState) {
+        const clock = transaction.beforeState.get(client) || 0
+        if (afterClock === clock) {
+          continue
+        }
+        iterateStructs(transaction, /** @type {Array<Item|GC>} */ (doc.store.clients.get(client)), clock, afterClock, item => {
+          // @ts-ignore
+          if (!item.deleted && item.content.constructor === ContentFormat) {
+            foundFormattingItem = true
+          }
+        })
+        if (foundFormattingItem) {
+          break
+        }
+      }
+      transact(doc, t => {
+        if (foundFormattingItem) {
+          // If a formatting item was inserted, we simply clean the whole type.
+          // We need to compute currentAttributes for the current position anyway.
+          cleanupYTextFormatting(this)
+        } else {
+          // If no formatting attribute was inserted, we can make due with contextless
+          // formatting cleanups.
+          // Contextless: it is not necessary to compute currentAttributes for the affected position.
+          iterateDeletedStructs(t, transaction.deleteSet, item => {
+            if (item instanceof GC) {
+              return
+            }
+            if (item.parent === this) {
+              cleanupContextlessFormattingGap(t, item)
+            }
+          })
+        }
+      })
+    }
+    callTypeObservers(this, transaction, event)
   }
 
   /**
@@ -692,16 +845,19 @@ export class YText extends AbstractType {
    * Apply a {@link Delta} on this shared YText type.
    *
    * @param {any} delta The changes to apply on this element.
+   * @param {object}  [opts]
+   * @param {boolean} [opts.sanitize] Sanitize input delta. Removes ending newlines if set to true.
+   *
    *
    * @public
    */
-  applyDelta (delta) {
+  applyDelta (delta, { sanitize = true } = {}) {
     if (this.doc !== null) {
       transact(this.doc, transaction => {
         /**
          * @type {ItemListPosition}
          */
-        let pos = new ItemListPosition(null, this._start)
+        const currPos = new ItemListPosition(null, this._start)
         const currentAttributes = new Map()
         for (let i = 0; i < delta.length; i++) {
           const op = delta[i]
@@ -711,14 +867,14 @@ export class YText extends AbstractType {
             // there is a newline at the end of the content.
             // If we omit this step, clients will see a different number of
             // paragraphs, but nothing bad will happen.
-            const ins = (typeof op.insert === 'string' && i === delta.length - 1 && pos.right === null && op.insert.slice(-1) === '\n') ? op.insert.slice(0, -1) : op.insert
+            const ins = (!sanitize && typeof op.insert === 'string' && i === delta.length - 1 && currPos.right === null && op.insert.slice(-1) === '\n') ? op.insert.slice(0, -1) : op.insert
             if (typeof ins !== 'string' || ins.length > 0) {
-              pos = insertText(transaction, this, pos.left, pos.right, currentAttributes, ins, op.attributes || {})
+              insertText(transaction, this, currPos, currentAttributes, ins, op.attributes || {})
             }
           } else if (op.retain !== undefined) {
-            pos = formatText(transaction, this, pos.left, pos.right, currentAttributes, op.retain, op.attributes || {})
+            formatText(transaction, this, currPos, currentAttributes, op.retain, op.attributes || {})
           } else if (op.delete !== undefined) {
-            pos = deleteText(transaction, pos.left, pos.right, currentAttributes, op.delete)
+            deleteText(transaction, currPos, currentAttributes, op.delete)
           }
         }
       })
@@ -800,12 +956,24 @@ export class YText extends AbstractType {
               str += /** @type {ContentString} */ (n.content).str
               break
             }
-            case ContentEmbed:
+            case ContentEmbed: {
               packStr()
-              ops.push({
+              /**
+               * @type {Object<string,any>}
+               */
+              const op = {
                 insert: /** @type {ContentEmbed} */ (n.content).embed
-              })
+              }
+              if (currentAttributes.size > 0) {
+                const attrs = /** @type {Object<string,any>} */ ({})
+                op.attributes = attrs
+                for (const [key, value] of currentAttributes) {
+                  attrs[key] = value
+                }
+              }
+              ops.push(op)
               break
+            }
             case ContentFormat:
               if (isVisible(n, snapshot)) {
                 packStr()
@@ -844,7 +1012,7 @@ export class YText extends AbstractType {
           // @ts-ignore
           currentAttributes.forEach((v, k) => { attributes[k] = v })
         }
-        insertText(transaction, this, left, right, currentAttributes, text, attributes)
+        insertText(transaction, this, new ItemListPosition(left, right), currentAttributes, text, attributes)
       })
     } else {
       /** @type {Array<function>} */ (this._pending).push(() => this.insert(index, text, attributes))
@@ -869,7 +1037,7 @@ export class YText extends AbstractType {
     if (y !== null) {
       transact(y, transaction => {
         const { left, right, currentAttributes } = findPosition(transaction, this, index)
-        insertText(transaction, this, left, right, currentAttributes, embed, attributes)
+        insertText(transaction, this, new ItemListPosition(left, right), currentAttributes, embed, attributes)
       })
     } else {
       /** @type {Array<function>} */ (this._pending).push(() => this.insertEmbed(index, embed, attributes))
@@ -892,7 +1060,7 @@ export class YText extends AbstractType {
     if (y !== null) {
       transact(y, transaction => {
         const { left, right, currentAttributes } = findPosition(transaction, this, index)
-        deleteText(transaction, left, right, currentAttributes, length)
+        deleteText(transaction, new ItemListPosition(left, right), currentAttributes, length)
       })
     } else {
       /** @type {Array<function>} */ (this._pending).push(() => this.delete(index, length))
@@ -910,6 +1078,9 @@ export class YText extends AbstractType {
    * @public
    */
   format (index, length, attributes) {
+    if (length === 0) {
+      return
+    }
     const y = this.doc
     if (y !== null) {
       transact(y, transaction => {
@@ -917,7 +1088,7 @@ export class YText extends AbstractType {
         if (right === null) {
           return
         }
-        formatText(transaction, this, left, right, currentAttributes, length, attributes)
+        formatText(transaction, this, new ItemListPosition(left, right), currentAttributes, length, attributes)
       })
     } else {
       /** @type {Array<function>} */ (this._pending).push(() => this.format(index, length, attributes))
@@ -926,8 +1097,6 @@ export class YText extends AbstractType {
 
   /**
    * @param {encoding.Encoder} encoder
-   *
-   * @private
    */
   _write (encoder) {
     encoding.writeVarUint(encoder, YTextRefID)

src/types/YXmlElement.js

@@ -27,7 +27,6 @@ export class YXmlElement extends YXmlFragment {
     this.nodeName = nodeName
     /**
      * @type {Map<string, any>|null}
-     * @private
      */
     this._prelimAttrs = new Map()
   }
@@ -41,7 +40,6 @@ export class YXmlElement extends YXmlFragment {
    *
    * @param {Doc} y The Yjs instance
    * @param {Item} item
-   * @private
    */
   _integrate (y, item) {
     super._integrate(y, item)
@@ -55,7 +53,6 @@ export class YXmlElement extends YXmlFragment {
    * Creates an Item with the same effect as this Item (without position effect)
    *
    * @return {YXmlElement}
-   * @private
    */
   _copy () {
     return new YXmlElement(this.nodeName)
@@ -184,7 +181,6 @@ export class YXmlElement extends YXmlFragment {
    *
    * This is called when this Item is sent to a remote peer.
    *
-   * @private
    * @param {encoding.Encoder} encoder The encoder to write data to.
    */
   _write (encoder) {
@@ -197,7 +193,6 @@ export class YXmlElement extends YXmlFragment {
  * @param {decoding.Decoder} decoder
  * @return {YXmlElement}
  *
- * @private
  * @function
  */
 export const readYXmlElement = decoder => new YXmlElement(decoding.readVarString(decoder))

src/types/YXmlFragment.js

@@ -48,7 +48,7 @@ import * as decoding from 'lib0/decoding.js' // eslint-disable-line
  * Can be created with {@link YXmlFragment#createTreeWalker}
  *
  * @public
- * @implements {IterableIterator}
+ * @implements {Iterable<YXmlElement|YXmlText|YXmlElement|YXmlHook>}
  */
 export class YXmlTreeWalker {
   /**
@@ -81,10 +81,10 @@ export class YXmlTreeWalker {
      * @type {Item|null}
      */
     let n = this._currentNode
-    let type = /** @type {ContentType} */ (n.content).type
+    let type = /** @type {any} */ (n.content).type
     if (n !== null && (!this._firstCall || n.deleted || !this._filter(type))) { // if first call, we check if we can use the first item
       do {
-        type = /** @type {ContentType} */ (n.content).type
+        type = /** @type {any} */ (n.content).type
         if (!n.deleted && (type.constructor === YXmlElement || type.constructor === YXmlFragment) && type._start !== null) {
           // walk down in the tree
           n = type._start
@@ -97,7 +97,7 @@ export class YXmlTreeWalker {
             } else if (n.parent === this._root) {
               n = null
             } else {
-              n = n.parent._item
+              n = /** @type {AbstractType<any>} */ (n.parent)._item
             }
           }
         }
@@ -127,7 +127,6 @@ export class YXmlFragment extends AbstractType {
     super()
     /**
      * @type {Array<any>|null}
-     * @private
      */
     this._prelimContent = []
   }
@@ -141,7 +140,6 @@ export class YXmlFragment extends AbstractType {
    *
    * @param {Doc} y The Yjs instance
    * @param {Item} item
-   * @private
    */
   _integrate (y, item) {
     super._integrate(y, item)
@@ -224,7 +222,6 @@ export class YXmlFragment extends AbstractType {
 
   /**
    * Creates YXmlEvent and calls observers.
-   * @private
    *
    * @param {Transaction} transaction
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
@@ -328,7 +325,6 @@ export class YXmlFragment extends AbstractType {
    *
    * This is called when this Item is sent to a remote peer.
    *
-   * @private
    * @param {encoding.Encoder} encoder The encoder to write data to.
    */
   _write (encoder) {

src/types/YXmlHook.js

@@ -25,8 +25,6 @@ export class YXmlHook extends YMap {
 
   /**
    * Creates an Item with the same effect as this Item (without position effect)
-   *
-   * @private
    */
   _copy () {
     return new YXmlHook(this.hookName)
@@ -69,8 +67,6 @@ export class YXmlHook extends YMap {
    * This is called when this Item is sent to a remote peer.
    *
    * @param {encoding.Encoder} encoder The encoder to write data to.
-   *
-   * @private
    */
   _write (encoder) {
     super._write(encoder)

src/types/YXmlText.js

@@ -79,8 +79,6 @@ export class YXmlText extends YText {
 
   /**
    * @param {encoding.Encoder} encoder
-   *
-   * @private
    */
   _write (encoder) {
     encoding.writeVarUint(encoder, YXmlTextRefID)

src/utils/DeleteSet.js

@@ -1,11 +1,11 @@
 
 import {
   findIndexSS,
-  createID,
   getState,
   splitItem,
+  createID,
   iterateStructs,
-  Item, GC, StructStore, Transaction, ID // eslint-disable-line
+  Item, AbstractStruct, GC, StructStore, Transaction, ID // eslint-disable-line
 } from '../internals.js'
 
 import * as array from 'lib0/array.js'
@@ -42,7 +42,6 @@ export class DeleteSet {
   constructor () {
     /**
      * @type {Map<number,Array<DeleteItem>>}
-     * @private
      */
     this.clients = new Map()
   }

src/utils/Doc.js

@@ -17,6 +17,8 @@ import { Observable } from 'lib0/observable.js'
 import * as random from 'lib0/random.js'
 import * as map from 'lib0/map.js'
 
+export const generateNewClientId = random.uint32
+
 /**
  * A Yjs instance handles the state of shared data.
  * @extends Observable<string>
@@ -31,7 +33,7 @@ export class Doc extends Observable {
     super()
     this.gc = gc
     this.gcFilter = gcFilter
-    this.clientID = random.uint32()
+    this.clientID = generateNewClientId()
     /**
      * @type {Map<string, AbstractType<YEvent>>}
      */
@@ -39,12 +41,10 @@ export class Doc extends Observable {
     this.store = new StructStore()
     /**
      * @type {Transaction | null}
-     * @private
      */
     this._transaction = null
     /**
      * @type {Array<Transaction>}
-     * @private
      */
     this._transactionCleanups = []
   }
@@ -65,17 +65,17 @@ export class Doc extends Observable {
   }
 
   /**
-   * Define a shared data type.
+   * Get a shared data type by name. If it does not yet exist, define its type.
    *
    * Multiple calls of `y.get(name, TypeConstructor)` yield the same result
-   * and do not overwrite each other. I.e.
+   * and do not overwrite each other, i.e.
-   * `y.define(name, Y.Array) === y.define(name, Y.Array)`
+   *   `y.get(name, Y.Array) === y.get(name, Y.Array)`
    *
    * After this method is called, the type is also available on `y.share.get(name)`.
    *
    * *Best Practices:*
    * Define all types right after the Yjs instance is created and store them in a separate object.
-   * Also use the typed methods `getText(name)`, `getArray(name)`, ..
+   * Also use the typed methods `getText(name)`, `getArray(name)`, `getMap(name)`, etc.
    *
    * @example
    *   const y = new Y(..)
@@ -105,6 +105,7 @@ export class Doc extends Observable {
         t._map = type._map
         type._map.forEach(/** @param {Item?} n */ n => {
           for (; n !== null; n = n.left) {
+            // @ts-ignore
             n.parent = t
           }
         })
@@ -170,8 +171,6 @@ export class Doc extends Observable {
 
   /**
    * Emit `destroy` event and unregister all event handlers.
-   *
-   * @protected
    */
   destroy () {
     this.emit('destroyed', [true])

src/utils/RelativePosition.js

@@ -1,12 +1,12 @@
 
 import {
-  createID,
   writeID,
   readID,
   compareIDs,
   getState,
   findRootTypeKey,
   Item,
+  createID,
   ContentType,
   followRedone,
   ID, Doc, AbstractType // eslint-disable-line
@@ -107,7 +107,7 @@ export const createRelativePosition = (type, item) => {
   if (type._item === null) {
     tname = findRootTypeKey(type)
   } else {
-    typeid = type._item.id
+    typeid = createID(type._item.id.client, type._item.id.clock)
   }
   return new RelativePosition(typeid, tname, item)
 }
@@ -227,7 +227,7 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
     if (!(right instanceof Item)) {
       return null
     }
-    type = right.parent
+    type = /** @type {AbstractType<any>} */ (right.parent)
     if (type._item === null || !type._item.deleted) {
       index = right.deleted || !right.countable ? 0 : res.diff
       let n = right.left

src/utils/Snapshot.js

@@ -4,13 +4,13 @@ import {
   createDeleteSetFromStructStore,
   getStateVector,
   getItemCleanStart,
-  createID,
   iterateDeletedStructs,
   writeDeleteSet,
   writeStateVector,
   readDeleteSet,
   readStateVector,
   createDeleteSet,
+  createID,
   getState,
   Transaction, Doc, DeleteSet, Item // eslint-disable-line
 } from '../internals.js'
@@ -28,13 +28,11 @@ export class Snapshot {
   constructor (ds, sv) {
     /**
      * @type {DeleteSet}
-     * @private
      */
     this.ds = ds
     /**
      * State Map
      * @type {Map<number,number>}
-     * @private
      */
     this.sv = sv
   }

src/utils/StructStore.js

@@ -2,7 +2,7 @@
 import {
   GC,
   splitItem,
-  GCRef, ItemRef, Transaction, ID, Item // eslint-disable-line
+  AbstractStruct, Transaction, ID, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as math from 'lib0/math.js'
@@ -13,7 +13,6 @@ export class StructStore {
   constructor () {
     /**
      * @type {Map<number,Array<GC|Item>>}
-     * @private
      */
     this.clients = new Map()
     /**
@@ -22,20 +21,17 @@ export class StructStore {
      * We could shift the array of refs instead, but shift is incredible
      * slow in Chrome for arrays with more than 100k elements
      * @see tryResumePendingStructRefs
-     * @type {Map<number,{i:number,refs:Array<GCRef|ItemRef>}>}
+     * @type {Map<number,{i:number,refs:Array<GC|Item>}>}
-     * @private
      */
     this.pendingClientsStructRefs = new Map()
     /**
      * Stack of pending structs waiting for struct dependencies
      * Maximum length of stack is structReaders.size
-     * @type {Array<GCRef|ItemRef>}
+     * @type {Array<GC|Item>}
-     * @private
      */
     this.pendingStack = []
     /**
      * @type {Array<decoding.Decoder>}
-     * @private
      */
     this.pendingDeleteReaders = []
   }
@@ -118,7 +114,7 @@ export const addStruct = (store, struct) => {
 
 /**
  * Perform a binary search on a sorted array
- * @param {Array<any>} structs
+ * @param {Array<Item|GC>} structs
  * @param {number} clock
  * @return {number}
  *
@@ -128,10 +124,18 @@ export const addStruct = (store, struct) => {
 export const findIndexSS = (structs, clock) => {
   let left = 0
   let right = structs.length - 1
+  let mid = structs[right]
+  let midclock = mid.id.clock
+  if (midclock === clock) {
+    return right
+  }
+  // @todo does it even make sense to pivot the search?
+  // If a good split misses, it might actually increase the time to find the correct item.
+  // Currently, the only advantage is that search with pivoting might find the item on the first try.
+  let midindex = math.floor((clock / (midclock + mid.length - 1)) * right) // pivoting the search
   while (left <= right) {
-    const midindex = math.floor((left + right) / 2)
+    mid = structs[midindex]
-    const mid = structs[midindex]
+    midclock = mid.id.clock
-    const midclock = mid.id.clock
     if (midclock <= clock) {
       if (clock < midclock + mid.length) {
         return midindex
@@ -140,6 +144,7 @@ export const findIndexSS = (structs, clock) => {
     } else {
       right = midindex - 1
     }
+    midindex = math.floor((left + right) / 2)
   }
   // Always check state before looking for a struct in StructStore
   // Therefore the case of not finding a struct is unexpected
@@ -167,16 +172,10 @@ export const find = (store, id) => {
 
 /**
  * Expects that id is actually in store. This function throws or is an infinite loop otherwise.
- *
- * @param {StructStore} store
- * @param {ID} id
- * @return {Item}
- *
  * @private
  * @function
  */
-// @ts-ignore
+export const getItem = /** @type {function(StructStore,ID):Item} */ (find)
-export const getItem = (store, id) => find(store, id)
 
 /**
  * @param {Transaction} transaction

src/utils/Transaction.js

@@ -1,7 +1,6 @@
 
 import {
   getState,
-  createID,
   writeStructsFromTransaction,
   writeDeleteSet,
   DeleteSet,
@@ -10,13 +9,16 @@ import {
   findIndexSS,
   callEventHandlerListeners,
   Item,
-  StructStore, ID, AbstractType, AbstractStruct, YEvent, Doc // eslint-disable-line
+  generateNewClientId,
+  createID,
+  GC, StructStore, ID, AbstractType, AbstractStruct, YEvent, Doc // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
 import * as map from 'lib0/map.js'
 import * as math from 'lib0/math.js'
 import * as set from 'lib0/set.js'
+import * as logging from 'lib0/logging.js'
 import { callAll } from 'lib0/function.js'
 
 /**
@@ -84,10 +86,9 @@ export class Transaction {
      */
     this.changedParentTypes = new Map()
     /**
-     * @type {Set<ID>}
+     * @type {Array<AbstractStruct>}
-     * @private
      */
-    this._mergeStructs = new Set()
+    this._mergeStructs = []
     /**
      * @type {any}
      */
@@ -155,8 +156,8 @@ const tryToMergeWithLeft = (structs, pos) => {
   if (left.deleted === right.deleted && left.constructor === right.constructor) {
     if (left.mergeWith(right)) {
       structs.splice(pos, 1)
-      if (right instanceof Item && right.parentSub !== null && right.parent._map.get(right.parentSub) === right) {
+      if (right instanceof Item && right.parentSub !== null && /** @type {AbstractType<any>} */ (right.parent)._map.get(right.parentSub) === right) {
-        right.parent._map.set(right.parentSub, /** @type {Item} */ (left))
+        /** @type {AbstractType<any>} */ (right.parent)._map.set(right.parentSub, /** @type {Item} */ (left))
       }
     }
   }
@@ -169,7 +170,7 @@ const tryToMergeWithLeft = (structs, pos) => {
  */
 const tryGcDeleteSet = (ds, store, gcFilter) => {
   for (const [client, deleteItems] of ds.clients) {
-    const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
+    const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
     for (let di = deleteItems.length - 1; di >= 0; di--) {
       const deleteItem = deleteItems[di]
       const endDeleteItemClock = deleteItem.clock + deleteItem.len
@@ -198,7 +199,7 @@ const tryMergeDeleteSet = (ds, store) => {
   // try to merge deleted / gc'd items
   // merge from right to left for better efficiecy and so we don't miss any merge targets
   for (const [client, deleteItems] of ds.clients) {
-    const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
+    const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
     for (let di = deleteItems.length - 1; di >= 0; di--) {
       const deleteItem = deleteItems[di]
       // start with merging the item next to the last deleted item
@@ -234,6 +235,7 @@ const cleanupTransactions = (transactionCleanups, i) => {
     const doc = transaction.doc
     const store = doc.store
     const ds = transaction.deleteSet
+    const mergeStructs = transaction._mergeStructs
     try {
       sortAndMergeDeleteSet(ds)
       transaction.afterState = getStateVector(transaction.doc.store)
@@ -291,7 +293,7 @@ const cleanupTransactions = (transactionCleanups, i) => {
       for (const [client, clock] of transaction.afterState) {
         const beforeClock = transaction.beforeState.get(client) || 0
         if (beforeClock !== clock) {
-          const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
+          const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
           // we iterate from right to left so we can safely remove entries
           const firstChangePos = math.max(findIndexSS(structs, beforeClock), 1)
           for (let i = structs.length - 1; i >= firstChangePos; i--) {
@@ -302,10 +304,9 @@ const cleanupTransactions = (transactionCleanups, i) => {
       // try to merge mergeStructs
       // @todo: it makes more sense to transform mergeStructs to a DS, sort it, and merge from right to left
       //        but at the moment DS does not handle duplicates
-      for (const mid of transaction._mergeStructs) {
+      for (let i = 0; i < mergeStructs.length; i++) {
-        const client = mid.client
+        const { client, clock } = mergeStructs[i].id
-        const clock = mid.clock
+        const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
-        const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
         const replacedStructPos = findIndexSS(structs, clock)
         if (replacedStructPos + 1 < structs.length) {
           tryToMergeWithLeft(structs, replacedStructPos + 1)
@@ -314,6 +315,10 @@ const cleanupTransactions = (transactionCleanups, i) => {
           tryToMergeWithLeft(structs, replacedStructPos)
         }
       }
+      if (!transaction.local && transaction.afterState.get(doc.clientID) !== transaction.beforeState.get(doc.clientID)) {
+        doc.clientID = generateNewClientId()
+        logging.print(logging.ORANGE, logging.BOLD, '[yjs] ', logging.UNBOLD, logging.RED, 'Changed the client-id because another client seems to be using it.')
+      }
       // @todo Merge all the transactions into one and provide send the data as a single update message
       doc.emit('afterTransactionCleanup', [transaction, doc])
       if (doc._observers.has('update')) {
@@ -338,7 +343,6 @@ const cleanupTransactions = (transactionCleanups, i) => {
  * @param {function(Transaction):void} f
  * @param {any} [origin=true]
  *
- * @private
  * @function
  */
 export const transact = (doc, f, origin = null, local = true) => {

src/utils/UndoManager.js

@@ -3,14 +3,14 @@ import {
   iterateDeletedStructs,
   keepItem,
   transact,
+  createID,
   redoItem,
   iterateStructs,
   isParentOf,
-  createID,
   followRedone,
   getItemCleanStart,
   getState,
-  Transaction, Doc, Item, GC, DeleteSet, AbstractType // eslint-disable-line
+  ID, Transaction, Doc, Item, GC, DeleteSet, AbstractType // eslint-disable-line
 } from '../internals.js'
 
 import * as time from 'lib0/time.js'
@@ -19,13 +19,13 @@ import { Observable } from 'lib0/observable.js'
 class StackItem {
   /**
    * @param {DeleteSet} ds
-   * @param {number} start clock start of the local client
+   * @param {Map<number,number>} beforeState
-   * @param {number} len
+   * @param {Map<number,number>} afterState
    */
-  constructor (ds, start, len) {
+  constructor (ds, beforeState, afterState) {
     this.ds = ds
-    this.start = start
+    this.beforeState = beforeState
-    this.len = len
+    this.afterState = afterState
     /**
      * Use this to save and restore metadata like selection range
      */
@@ -50,47 +50,37 @@ const popStackItem = (undoManager, stack, eventType) => {
   transact(doc, transaction => {
     while (stack.length > 0 && result === null) {
       const store = doc.store
-      const clientID = doc.clientID
       const stackItem = /** @type {StackItem} */ (stack.pop())
-      const stackStartClock = stackItem.start
+      /**
-      const stackEndClock = stackItem.start + stackItem.len
+       * @type {Set<Item>}
+       */
       const itemsToRedo = new Set()
-      // @todo iterateStructs should not need the structs parameter
-      const structs = /** @type {Array<GC|Item>} */ (store.clients.get(clientID))
-      let performedChange = false
-      if (stackStartClock !== stackEndClock) {
-        // make sure structs don't overlap with the range of created operations [stackItem.start, stackItem.start + stackItem.end)
-        getItemCleanStart(transaction, createID(clientID, stackStartClock))
-        if (stackEndClock < getState(doc.store, clientID)) {
-          getItemCleanStart(transaction, createID(clientID, stackEndClock))
-        }
-      }
-      iterateDeletedStructs(transaction, stackItem.ds, struct => {
-        if (
-          struct instanceof Item &&
-          scope.some(type => isParentOf(type, struct)) &&
-          // Never redo structs in [stackItem.start, stackItem.start + stackItem.end) because they were created and deleted in the same capture interval.
-          !(struct.id.client === clientID && struct.id.clock >= stackStartClock && struct.id.clock < stackEndClock)
-        ) {
-          itemsToRedo.add(struct)
-        }
-      })
-      itemsToRedo.forEach(struct => {
-        performedChange = redoItem(transaction, struct, itemsToRedo) !== null || performedChange
-      })
       /**
        * @type {Array<Item>}
        */
       const itemsToDelete = []
-      iterateStructs(transaction, structs, stackStartClock, stackItem.len, struct => {
+      let performedChange = false
+      stackItem.afterState.forEach((endClock, client) => {
+        const startClock = stackItem.beforeState.get(client) || 0
+        const len = endClock - startClock
+        // @todo iterateStructs should not need the structs parameter
+        const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
+        if (startClock !== endClock) {
+          // make sure structs don't overlap with the range of created operations [stackItem.start, stackItem.start + stackItem.end)
+          // this must be executed before deleted structs are iterated.
+          getItemCleanStart(transaction, createID(client, startClock))
+          if (endClock < getState(doc.store, client)) {
+            getItemCleanStart(transaction, createID(client, endClock))
+          }
+          iterateStructs(transaction, structs, startClock, len, struct => {
             if (struct instanceof Item) {
               if (struct.redone !== null) {
                 let { item, diff } = followRedone(store, struct.id)
                 if (diff > 0) {
                   item = getItemCleanStart(transaction, createID(item.id.client, item.id.clock + diff))
                 }
-            if (item.length > stackItem.len) {
+                if (item.length > len) {
-              getItemCleanStart(transaction, createID(item.id.client, stackEndClock))
+                  getItemCleanStart(transaction, createID(item.id.client, endClock))
                 }
                 struct = item
               }
@@ -99,6 +89,26 @@ const popStackItem = (undoManager, stack, eventType) => {
               }
             }
           })
+        }
+      })
+      iterateDeletedStructs(transaction, stackItem.ds, struct => {
+        const id = struct.id
+        const clock = id.clock
+        const client = id.client
+        const startClock = stackItem.beforeState.get(client) || 0
+        const endClock = stackItem.afterState.get(client) || 0
+        if (
+          struct instanceof Item &&
+          scope.some(type => isParentOf(type, struct)) &&
+          // Never redo structs in [stackItem.start, stackItem.start + stackItem.end) because they were created and deleted in the same capture interval.
+          !(clock >= startClock && clock < endClock)
+        ) {
+          itemsToRedo.add(struct)
+        }
+      })
+      itemsToRedo.forEach(struct => {
+        performedChange = redoItem(transaction, struct, itemsToRedo) !== null || performedChange
+      })
       // We want to delete in reverse order so that children are deleted before
       // parents, so we have more information available when items are filtered.
       for (let i = itemsToDelete.length - 1; i >= 0; i--) {
@@ -181,17 +191,17 @@ export class UndoManager extends Observable {
         // neither undoing nor redoing: delete redoStack
         this.redoStack = []
       }
-      const beforeState = transaction.beforeState.get(this.doc.clientID) || 0
+      const beforeState = transaction.beforeState
-      const afterState = transaction.afterState.get(this.doc.clientID) || 0
+      const afterState = transaction.afterState
       const now = time.getUnixTime()
       if (now - this.lastChange < captureTimeout && stack.length > 0 && !undoing && !redoing) {
         // append change to last stack op
         const lastOp = stack[stack.length - 1]
         lastOp.ds = mergeDeleteSets([lastOp.ds, transaction.deleteSet])
-        lastOp.len = afterState - lastOp.start
+        lastOp.afterState = afterState
       } else {
         // create a new stack op
-        stack.push(new StackItem(transaction.deleteSet, beforeState, afterState - beforeState))
+        stack.push(new StackItem(transaction.deleteSet, beforeState, afterState))
       }
       if (!undoing && !redoing) {
         this.lastChange = now

src/utils/YEvent.js

@@ -211,7 +211,7 @@ const getPathTo = (parent, child) => {
     } else {
       // parent is array-ish
       let i = 0
-      let c = child._item.parent._start
+      let c = /** @type {AbstractType<any>} */ (child._item.parent)._start
       while (c !== child._item && c !== null) {
         if (!c.deleted) {
           i++
@@ -220,7 +220,7 @@ const getPathTo = (parent, child) => {
       }
       path.unshift(i)
     }
-    child = child._item.parent
+    child = /** @type {AbstractType<any>} */ (child._item.parent)
   }
   return path
 }

src/utils/encoding.js

@@ -16,18 +16,17 @@
 
 import {
   findIndexSS,
-  GCRef,
-  ItemRef,
   writeID,
-  createID,
   readID,
   getState,
+  createID,
   getStateVector,
   readAndApplyDeleteSet,
   writeDeleteSet,
   createDeleteSetFromStructStore,
   transact,
-  Doc, Transaction, AbstractStruct, StructStore, ID // eslint-disable-line
+  readItem,
+  Doc, Transaction, GC, Item, StructStore, ID // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -36,7 +35,7 @@ import * as binary from 'lib0/binary.js'
 
 /**
  * @param {encoding.Encoder} encoder
- * @param {Array<AbstractStruct>} structs All structs by `client`
+ * @param {Array<GC|Item>} structs All structs by `client`
  * @param {number} client
  * @param {number} clock write structs starting with `ID(client,clock)`
  *
@@ -50,35 +49,12 @@ const writeStructs = (encoder, structs, client, clock) => {
   writeID(encoder, createID(client, clock))
   const firstStruct = structs[startNewStructs]
   // write first struct with an offset
-  firstStruct.write(encoder, clock - firstStruct.id.clock, 0)
+  firstStruct.write(encoder, clock - firstStruct.id.clock)
   for (let i = startNewStructs + 1; i < structs.length; i++) {
-    structs[i].write(encoder, 0, 0)
+    structs[i].write(encoder, 0)
   }
 }
 
-/**
- * @param {decoding.Decoder} decoder
- * @param {number} numOfStructs
- * @param {ID} nextID
- * @return {Array<GCRef|ItemRef>}
- *
- * @private
- * @function
- */
-const readStructRefs = (decoder, numOfStructs, nextID) => {
-  /**
-   * @type {Array<GCRef|ItemRef>}
-   */
-  const refs = []
-  for (let i = 0; i < numOfStructs; i++) {
-    const info = decoding.readUint8(decoder)
-    const ref = (binary.BITS5 & info) === 0 ? new GCRef(decoder, nextID, info) : new ItemRef(decoder, nextID, info)
-    nextID = createID(nextID.client, nextID.clock + ref.length)
-    refs.push(ref)
-  }
-  return refs
-}
-
 /**
  * @param {encoding.Encoder} encoder
  * @param {StructStore} store
@@ -103,7 +79,9 @@ export const writeClientsStructs = (encoder, store, _sm) => {
   })
   // write # states that were updated
   encoding.writeVarUint(encoder, sm.size)
-  sm.forEach((clock, client) => {
+  // Write items with higher client ids first
+  // This heavily improves the conflict algorithm.
+  Array.from(sm.entries()).sort((a, b) => b[0] - a[0]).forEach(([client, clock]) => {
     // @ts-ignore
     writeStructs(encoder, store.clients.get(client), client, clock)
   })
@@ -111,22 +89,30 @@ export const writeClientsStructs = (encoder, store, _sm) => {
 
 /**
  * @param {decoding.Decoder} decoder The decoder object to read data from.
- * @return {Map<number,Array<GCRef|ItemRef>>}
+ * @param {Map<number,Array<GC|Item>>} clientRefs
+ * @param {Doc} doc
+ * @return {Map<number,Array<GC|Item>>}
  *
  * @private
  * @function
  */
-export const readClientsStructRefs = decoder => {
+export const readClientsStructRefs = (decoder, clientRefs, doc) => {
-  /**
-   * @type {Map<number,Array<GCRef|ItemRef>>}
-   */
-  const clientRefs = new Map()
   const numOfStateUpdates = decoding.readVarUint(decoder)
   for (let i = 0; i < numOfStateUpdates; i++) {
     const numberOfStructs = decoding.readVarUint(decoder)
-    const nextID = readID(decoder)
+    /**
-    const refs = readStructRefs(decoder, numberOfStructs, nextID)
+     * @type {Array<GC|Item>}
-    clientRefs.set(nextID.client, refs)
+     */
+    const refs = []
+    let { client, clock } = readID(decoder)
+    let info, struct
+    clientRefs.set(client, refs)
+    for (let i = 0; i < numberOfStructs; i++) {
+      info = decoding.readUint8(decoder)
+      struct = (binary.BITS5 & info) === 0 ? new GC(createID(client, clock), decoding.readVarUint(decoder)) : readItem(decoder, createID(client, clock), info, doc)
+      refs.push(struct)
+      clock += struct.length
+    }
   }
   return clientRefs
 }
@@ -159,28 +145,36 @@ export const readClientsStructRefs = decoder => {
 const resumeStructIntegration = (transaction, store) => {
   const stack = store.pendingStack
   const clientsStructRefs = store.pendingClientsStructRefs
+  // sort them so that we take the higher id first, in case of conflicts the lower id will probably not conflict with the id from the higher user.
+  const clientsStructRefsIds = Array.from(clientsStructRefs.keys()).sort((a, b) => a - b)
+  let curStructsTarget = /** @type {{i:number,refs:Array<GC|Item>}} */ (clientsStructRefs.get(clientsStructRefsIds[clientsStructRefsIds.length - 1]))
   // iterate over all struct readers until we are done
-  while (stack.length !== 0 || clientsStructRefs.size !== 0) {
+  while (stack.length !== 0 || clientsStructRefsIds.length > 0) {
     if (stack.length === 0) {
       // take any first struct from clientsStructRefs and put it on the stack
-      const [client, structRefs] = clientsStructRefs.entries().next().value
+      if (curStructsTarget.i < curStructsTarget.refs.length) {
-      stack.push(structRefs.refs[structRefs.i++])
+        stack.push(curStructsTarget.refs[curStructsTarget.i++])
-      if (structRefs.refs.length === structRefs.i) {
+      } else {
-        clientsStructRefs.delete(client)
+        clientsStructRefsIds.pop()
+        if (clientsStructRefsIds.length > 0) {
+          curStructsTarget = /** @type {{i:number,refs:Array<GC|Item>}} */ (clientsStructRefs.get(clientsStructRefsIds[clientsStructRefsIds.length - 1]))
+        }
+        continue
       }
     }
     const ref = stack[stack.length - 1]
-    const m = ref._missing
+    const refID = ref.id
-    const client = ref.id.client
+    const client = refID.client
+    const refClock = refID.clock
     const localClock = getState(store, client)
-    const offset = ref.id.clock < localClock ? localClock - ref.id.clock : 0
+    const offset = refClock < localClock ? localClock - refClock : 0
-    if (ref.id.clock + offset !== localClock) {
+    if (refClock + offset !== localClock) {
       // A previous message from this client is missing
       // check if there is a pending structRef with a smaller clock and switch them
-      const structRefs = clientsStructRefs.get(client)
+      const structRefs = clientsStructRefs.get(client) || { refs: [], i: 0 }
-      if (structRefs !== undefined) {
+      if (structRefs.refs.length !== structRefs.i) {
         const r = structRefs.refs[structRefs.i]
-        if (r.id.clock < ref.id.clock) {
+        if (r.id.clock < refClock) {
           // put ref with smaller clock on stack instead and continue
           structRefs.refs[structRefs.i] = ref
           stack[stack.length - 1] = r
@@ -193,31 +187,23 @@ const resumeStructIntegration = (transaction, store) => {
       // wait until missing struct is available
       return
     }
-    while (m.length > 0) {
+    const missing = ref.getMissing(transaction, store)
-      const missing = m[m.length - 1]
+    if (missing !== null) {
-      if (getState(store, missing.client) <= missing.clock) {
-        const client = missing.client
       // get the struct reader that has the missing struct
-        const structRefs = clientsStructRefs.get(client)
+      const structRefs = clientsStructRefs.get(missing) || { refs: [], i: 0 }
-        if (structRefs === undefined) {
+      if (structRefs.refs.length === structRefs.i) {
         // This update message causally depends on another update message.
         return
       }
       stack.push(structRefs.refs[structRefs.i++])
-        if (structRefs.i === structRefs.refs.length) {
+    } else {
-          clientsStructRefs.delete(client)
-        }
-        break
-      }
-      ref._missing.pop()
-    }
-    if (m.length === 0) {
       if (offset < ref.length) {
-        ref.toStruct(transaction, store, offset).integrate(transaction)
+        ref.integrate(transaction, offset)
       }
       stack.pop()
     }
   }
+  store.pendingClientsStructRefs.clear()
 }
 
 /**
@@ -246,7 +232,7 @@ export const writeStructsFromTransaction = (encoder, transaction) => writeClient
 
 /**
  * @param {StructStore} store
- * @param {Map<number, Array<GCRef|ItemRef>>} clientsStructsRefs
+ * @param {Map<number, Array<GC|Item>>} clientsStructsRefs
  *
  * @private
  * @function
@@ -269,6 +255,21 @@ const mergeReadStructsIntoPendingReads = (store, clientsStructsRefs) => {
   }
 }
 
+/**
+ * @param {Map<number,{refs:Array<GC|Item>,i:number}>} pendingClientsStructRefs
+ */
+const cleanupPendingStructs = pendingClientsStructRefs => {
+  // cleanup pendingClientsStructs if not fully finished
+  for (const [client, refs] of pendingClientsStructRefs) {
+    if (refs.i === refs.refs.length) {
+      pendingClientsStructRefs.delete(client)
+    } else {
+      refs.refs.splice(0, refs.i)
+      refs.i = 0
+    }
+  }
+}
+
 /**
  * Read the next Item in a Decoder and fill this Item with the read data.
  *
@@ -282,9 +283,11 @@ const mergeReadStructsIntoPendingReads = (store, clientsStructsRefs) => {
  * @function
  */
 export const readStructs = (decoder, transaction, store) => {
-  const clientsStructRefs = readClientsStructRefs(decoder)
+  const clientsStructRefs = new Map()
+  readClientsStructRefs(decoder, clientsStructRefs, transaction.doc)
   mergeReadStructsIntoPendingReads(store, clientsStructRefs)
   resumeStructIntegration(transaction, store)
+  cleanupPendingStructs(store.pendingClientsStructRefs)
   tryResumePendingDeleteReaders(transaction, store)
 }
 

src/utils/isParentOf.js

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

tests/consistency.tests.js

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

tests/index.js

@@ -5,6 +5,7 @@ import * as text from './y-text.tests.js'
 import * as xml from './y-xml.tests.js'
 import * as encoding from './encoding.tests.js'
 import * as undoredo from './undo-redo.tests.js'
+import * as consistency from './consistency.tests.js'
 
 import { runTests } from 'lib0/testing.js'
 import { isBrowser, isNode } from 'lib0/environment.js'
@@ -14,7 +15,7 @@ if (isBrowser) {
   log.createVConsole(document.body)
 }
 runTests({
-  map, array, text, xml, encoding, undoredo
+  map, array, text, xml, consistency, encoding, undoredo
 }).then(success => {
   /* istanbul ignore next */
   if (isNode) {

tests/testHelper.js

@@ -330,6 +330,7 @@ export const compareStructStores = (ss1, ss2) => {
         s1.constructor !== s2.constructor ||
         !Y.compareIDs(s1.id, s2.id) ||
         s1.deleted !== s2.deleted ||
+        // @ts-ignore
         s1.length !== s2.length
       ) {
         t.fail('Structs dont match')

tests/y-map.tests.js

@@ -8,6 +8,33 @@ import * as Y from '../src/index.js'
 import * as t from 'lib0/testing.js'
 import * as prng from 'lib0/prng.js'
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testMapHavingIterableAsConstructorParamTests = tc => {
+  const { map0 } = init(tc, { users: 1 })
+
+  const m1 = new Y.Map(Object.entries({ number: 1, string: 'hello' }))
+  map0.set('m1', m1)
+  t.assert(m1.get('number') === 1)
+  t.assert(m1.get('string') === 'hello')
+
+  const m2 = new Y.Map([
+    ['object', { x: 1 }],
+    ['boolean', true]
+  ])
+  map0.set('m2', m2)
+  t.assert(m2.get('object').x === 1)
+  t.assert(m2.get('boolean') === true)
+
+  const m3 = new Y.Map([...m1, ...m2])
+  map0.set('m3', m3)
+  t.assert(m3.get('number') === 1)
+  t.assert(m3.get('string') === 'hello')
+  t.assert(m3.get('object').x === 1)
+  t.assert(m3.get('boolean') === true)
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -33,6 +60,7 @@ export const testBasicMapTests = tc => {
   t.assert(map0.get('boolean1') === true, 'client 0 computed the change (boolean)')
   t.compare(map0.get('object'), { key: { key2: 'value' } }, 'client 0 computed the change (object)')
   t.assert(map0.get('y-map').get('y-array').get(0) === -1, 'client 0 computed the change (type)')
+  t.assert(map0.size === 6, 'client 0 map has correct size')
 
   users[2].connect()
   testConnector.flushAllMessages()
@@ -43,6 +71,7 @@ export const testBasicMapTests = tc => {
   t.assert(map1.get('boolean1') === true, 'client 1 computed the change (boolean)')
   t.compare(map1.get('object'), { key: { key2: 'value' } }, 'client 1 received the update (object)')
   t.assert(map1.get('y-map').get('y-array').get(0) === -1, 'client 1 received the update (type)')
+  t.assert(map1.size === 6, 'client 1 map has correct size')
 
   // compare disconnected user
   t.assert(map2.get('number') === 1, 'client 2 received the update (number) - was disconnected')
@@ -130,6 +159,20 @@ export const testGetAndSetOfMapPropertyWithConflict = tc => {
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testSizeAndDeleteOfMapProperty = tc => {
+  const { map0 } = init(tc, { users: 1 })
+  map0.set('stuff', 'c0')
+  map0.set('otherstuff', 'c1')
+  t.assert(map0.size === 2, `map size is ${map0.size} expected 2`)
+  map0.delete('stuff')
+  t.assert(map0.size === 1, `map size after delete is ${map0.size}, expected 1`)
+  map0.delete('otherstuff')
+  t.assert(map0.size === 0, `map size after delete is ${map0.size}, expected 0`)
+}
+
 /**
  * @param {t.TestCase} tc
  */
@@ -454,7 +497,7 @@ const mapTransactions = [
  * @param {t.TestCase} tc
  */
 export const testRepeatGeneratingYmapTests10 = tc => {
-  applyRandomTests(tc, mapTransactions, 10)
+  applyRandomTests(tc, mapTransactions, 3)
 }
 
 /**

tests/y-text.tests.js

@@ -1,5 +1,8 @@
 import * as Y from './testHelper.js'
 import * as t from 'lib0/testing.js'
+import * as prng from 'lib0/prng.js'
+import * as math from 'lib0/math.js'
+
 const { init, compare } = Y
 
 /**
@@ -158,3 +161,248 @@ export const testToJson = tc => {
   text0.insert(0, 'abc', { bold: true })
   t.assert(text0.toJSON() === 'abc', 'toJSON returns the unformatted text')
 }
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testToDeltaEmbedAttributes = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  text0.insert(0, 'ab', { bold: true })
+  text0.insertEmbed(1, { image: 'imageSrc.png' }, { width: 100 })
+  const delta0 = text0.toDelta()
+  t.compare(delta0, [{ insert: 'a', attributes: { bold: true } }, { insert: { image: 'imageSrc.png' }, attributes: { width: 100 } }, { insert: 'b', attributes: { bold: true } }])
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testToDeltaEmbedNoAttributes = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  text0.insert(0, 'ab', { bold: true })
+  text0.insertEmbed(1, { image: 'imageSrc.png' })
+  const delta0 = text0.toDelta()
+  t.compare(delta0, [{ insert: 'a', attributes: { bold: true } }, { insert: { image: 'imageSrc.png' } }, { insert: 'b', attributes: { bold: true } }], 'toDelta does not set attributes key when no attributes are present')
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testFormattingRemoved = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  text0.insert(0, 'ab', { bold: true })
+  text0.delete(0, 2)
+  t.assert(Y.getTypeChildren(text0).length === 1)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testFormattingRemovedInMidText = tc => {
+  const { text0 } = init(tc, { users: 1 })
+  text0.insert(0, '1234')
+  text0.insert(2, 'ab', { bold: true })
+  text0.delete(2, 2)
+  t.assert(Y.getTypeChildren(text0).length === 3)
+}
+
+const tryGc = () => {
+  if (typeof global !== 'undefined' && global.gc) {
+    global.gc()
+  }
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testLargeFragmentedDocument = tc => {
+  const itemsToInsert = 2000000
+  let update = /** @type {any} */ (null)
+  ;(() => {
+    const doc1 = new Y.Doc()
+    const text0 = doc1.getText('txt')
+    tryGc()
+    t.measureTime(`time to insert ${itemsToInsert} items`, () => {
+      doc1.transact(() => {
+        for (let i = 0; i < itemsToInsert; i++) {
+          text0.insert(0, '0')
+        }
+      })
+    })
+    tryGc()
+    t.measureTime('time to encode document', () => {
+      update = Y.encodeStateAsUpdate(doc1)
+    })
+  })()
+  ;(() => {
+    const doc2 = new Y.Doc()
+    tryGc()
+    t.measureTime(`time to apply ${itemsToInsert} updates`, () => {
+      Y.applyUpdate(doc2, update)
+    })
+  })()
+}
+
+// RANDOM TESTS
+
+let charCounter = 0
+
+const marks = [
+  { bold: true },
+  { italic: true },
+  { italic: true, color: '#888' }
+]
+
+const marksChoices = [
+  undefined,
+  ...marks
+]
+
+/**
+ * @type Array<function(any,prng.PRNG):void>
+ */
+const qChanges = [
+  /**
+   * @param {Y.Doc} y
+   * @param {prng.PRNG} gen
+   */
+  (y, gen) => { // insert text
+    const ytext = y.getText('text')
+    const insertPos = prng.int32(gen, 0, ytext.toString().length)
+    const attrs = prng.oneOf(gen, marksChoices)
+    const text = charCounter++ + prng.word(gen)
+    ytext.insert(insertPos, text, attrs)
+  },
+  /**
+   * @param {Y.Doc} y
+   * @param {prng.PRNG} gen
+   */
+  (y, gen) => { // insert embed
+    const ytext = y.getText('text')
+    const insertPos = prng.int32(gen, 0, ytext.toString().length)
+    ytext.insertEmbed(insertPos, { image: 'https://user-images.githubusercontent.com/5553757/48975307-61efb100-f06d-11e8-9177-ee895e5916e5.png' })
+  },
+  /**
+   * @param {Y.Doc} y
+   * @param {prng.PRNG} gen
+   */
+  (y, gen) => { // delete text
+    const ytext = y.getText('text')
+    const contentLen = ytext.toString().length
+    const insertPos = prng.int32(gen, 0, contentLen)
+    const overwrite = math.min(prng.int32(gen, 0, contentLen - insertPos), 2)
+    ytext.delete(insertPos, overwrite)
+  },
+  /**
+   * @param {Y.Doc} y
+   * @param {prng.PRNG} gen
+   */
+  (y, gen) => { // format text
+    const ytext = y.getText('text')
+    const contentLen = ytext.toString().length
+    const insertPos = prng.int32(gen, 0, contentLen)
+    const overwrite = math.min(prng.int32(gen, 0, contentLen - insertPos), 2)
+    const format = prng.oneOf(gen, marks)
+    ytext.format(insertPos, overwrite, format)
+  },
+  /**
+   * @param {Y.Doc} y
+   * @param {prng.PRNG} gen
+   */
+  (y, gen) => { // insert codeblock
+    const ytext = y.getText('text')
+    const insertPos = prng.int32(gen, 0, ytext.toString().length)
+    const text = charCounter++ + prng.word(gen)
+    const ops = []
+    if (insertPos > 0) {
+      ops.push({ retain: insertPos })
+    }
+    ops.push({ insert: text }, { insert: '\n', format: { 'code-block': true } })
+    ytext.applyDelta(ops)
+  }
+]
+
+/**
+ * @param {any} result
+ */
+const checkResult = result => {
+  for (let i = 1; i < result.testObjects.length; i++) {
+    const p1 = result.users[i].getText('text').toDelta()
+    const p2 = result.users[i].getText('text').toDelta()
+    t.compare(p1, p2)
+  }
+  // Uncomment this to find formatting-cleanup issues
+  // const cleanups = Y.cleanupYTextFormatting(result.users[0].getText('text'))
+  // t.assert(cleanups === 0)
+  return result
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRepeatGenerateQuillChanges1 = tc => {
+  const { users } = checkResult(Y.applyRandomTests(tc, qChanges, 1))
+  const cleanups = Y.cleanupYTextFormatting(users[0].getText('text'))
+  t.assert(cleanups === 0)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRepeatGenerateQuillChanges2 = tc => {
+  const { users } = checkResult(Y.applyRandomTests(tc, qChanges, 2))
+  const cleanups = Y.cleanupYTextFormatting(users[0].getText('text'))
+  t.assert(cleanups === 0)
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRepeatGenerateQuillChanges2Repeat = tc => {
+  for (let i = 0; i < 1000; i++) {
+    const { users } = checkResult(Y.applyRandomTests(tc, qChanges, 2))
+    const cleanups = Y.cleanupYTextFormatting(users[0].getText('text'))
+    t.assert(cleanups === 0)
+  }
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRepeatGenerateQuillChanges3 = tc => {
+  checkResult(Y.applyRandomTests(tc, qChanges, 3))
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRepeatGenerateQuillChanges30 = tc => {
+  checkResult(Y.applyRandomTests(tc, qChanges, 30))
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRepeatGenerateQuillChanges40 = tc => {
+  checkResult(Y.applyRandomTests(tc, qChanges, 40))
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRepeatGenerateQuillChanges70 = tc => {
+  checkResult(Y.applyRandomTests(tc, qChanges, 70))
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRepeatGenerateQuillChanges100 = tc => {
+  checkResult(Y.applyRandomTests(tc, qChanges, 100))
+}
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRepeatGenerateQuillChanges300 = tc => {
+  checkResult(Y.applyRandomTests(tc, qChanges, 300))
+}

tsconfig.json

@@ -39,10 +39,7 @@
     "moduleResolution": "node",            /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
     "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
     "paths": {
-      "yjs": ["./src/index.js"],
+      "yjs": ["./src/index.js"]
-      "lib0/*": ["node_modules/lib0/*"],
-      "lib0/set.js": ["node_modules/lib0/set.js"],
-      "lib0/function.js": ["node_modules/lib0/function.js"]
     },                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
     // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
     // "typeRoots": [],                       /* List of folders to include type definitions from. */
@@ -60,9 +57,8 @@
     /* Experimental Options */
     // "experimentalDecorators": true,        /* Enables experimental support for ES7 decorators. */
     // "emitDecoratorMetadata": true,         /* Enables experimental support for emitting type metadata for decorators. */
-    "maxNodeModuleJsDepth": 5,
+    // "maxNodeModuleJsDepth": 0,
     // "types": ["./src/utils/typedefs.js"]
   },
-  "include": ["./src/**/*.js", "./tests/**/*.js"],
+  "include": ["./src/**/*.js", "./tests/**/*.js"]
-  "exclude": ["../lib0/**/*", "node_modules/**/*", "dist", "dist/**/*.js"]
 }