13.1.1

Add sanitize option

.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

@@ -25,6 +25,43 @@ 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)
+
+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.
+
 ## Table of Contents
 
 * [Overview](#Overview)
@@ -52,13 +89,10 @@ 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/) |
-| [Quill](https://quilljs.com/) | ✔ | [y-quill](http://github.com/yjs/y-quill) | [demo](https://yjs-demos.now.sh/quill/) |
-| [CodeMirror](https://codemirror.net/) | ✔ | [y-codemirror](http://github.com/yjs/y-codemirror) | [demo](https://yjs-demos.now.sh/codemirror/) |
-| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](http://github.com/yjs/y-monaco) | [demo](https://yjs-demos.now.sh/monaco/) |
-| [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/) |
+| [ProseMirror](https://prosemirror.net/) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; | ✔ | [y-prosemirror](http://github.com/yjs/y-prosemirror) | [demo](https://demos.yjs.dev/prosemirror/prosemirror.html) |
+| [Quill](https://quilljs.com/) | ✔ | [y-quill](http://github.com/yjs/y-quill) | [demo](https://demos.yjs.dev/quill/quill.html) |
+| [CodeMirror](https://codemirror.net/) | ✔ | [y-codemirror](http://github.com/yjs/y-codemirror) | [demo](https://demos.yjs.dev/codemirror/codemirror.html) |
+| [Monaco](https://microsoft.github.io/monaco-editor/) | ✔ | [y-monaco](http://github.com/yjs/y-monaco) | [demo](https://demos.yjs.dev/monaco/monaco.html) |
 
 ### Providers
 
@@ -140,6 +174,54 @@ 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
@@ -161,11 +243,13 @@ 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>
@@ -311,8 +395,12 @@ YTextEvents compute changes as deltas.
     <dd></dd>
     <b><code>format(index:number, length:number, formattingAttributes:Object&lt;string,string&gt;)</code></b>
     <dd>Assign formatting attributes to a range in the text</dd>
-    <b><code>applyDelta(delta)</code></b>
-    <dd>See <a href="https://quilljs.com/docs/delta/">Quill Delta</a></dd>
+    <b><code>applyDelta(delta, opts:Object&lt;string,any&gt;)</code></b>
+    <dd>
+        See <a href="https://quilljs.com/docs/delta/">Quill Delta</a>
+        Can set options for preventing remove ending newLines, default is true.
+        <pre>ytext.applyDelta(delta, { sanitize: false })</pre>
+    </dd>
     <b><code>length:number</code></b>
     <dd></dd>
     <b><code>toString():string</code></b>
@@ -466,6 +554,12 @@ 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
@@ -642,7 +736,7 @@ Yjs ships with an Undo/Redo manager for selective undo/redo of of changes on a
 Yjs type. The changes can be optionally scoped to transaction origins.
 
 ```js
-const ytext = doc.getArray('array')
+const ytext = doc.getText('text')
 const undoManager = new Y.UndoManager(ytext)
 
 ytext.insert(0, 'abc')
@@ -653,8 +747,8 @@ ytext.toString() // => 'abc'
 ```
 
 <dl>
-  <b><code>constructor(scope:Y.AbstractType|Array&lt;Y.AbstractType&gt;,
-  [[{captureTimeout:number,trackedOrigins:Set&lt;any&gt;,deleteFilter:function(item):boolean}]])</code></b>
+  <b><code>constructor(scope:Y.AbstractType|Array&lt;Y.AbstractType&gt;
+  [, {captureTimeout:number,trackedOrigins:Set&lt;any&gt;,deleteFilter:function(item):boolean}])</code></b>
   <dd>Accepts either single type as scope or an array of types.</dd>
   <b><code>undo()</code></b>
   <dd></dd>
@@ -694,28 +788,30 @@ 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 undoManager = new Y.UndoManager(ytext, new Set([42, CustomBinding]))
+const ytext = doc.getText('text')
+const undoManager = new Y.UndoManager(ytext, {
+  trackedOrigins: new Set([42, CustomBinding])
+})
 
 ytext.insert(0, 'abc')
 undoManager.undo()
@@ -752,8 +848,10 @@ 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 undoManager = new Y.UndoManager(ytext, new Set([42, CustomBinding]))
+const ytext = doc.getText('text')
+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": "13.0.5",
+  "version": "13.1.1",
   "description": "Shared Editing Library",
   "main": "./dist/yjs.cjs",
   "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": "^0.2.22"
+    "lib0": "^0.2.27"
   },
   "devDependencies": {
-    "@rollup/plugin-commonjs": "^11.0.1",
-    "@rollup/plugin-node-resolve": "^7.0.0",
+    "@rollup/plugin-commonjs": "^11.1.0",
+    "@rollup/plugin-node-resolve": "^7.1.3",
     "concurrently": "^3.6.1",
-    "http-server": "^0.12.1",
-    "jsdoc": "^3.6.3",
-    "markdownlint-cli": "^0.19.0",
-    "rollup": "^1.30.0",
+    "http-server": "^0.12.3",
+    "jsdoc": "^3.6.4",
+    "markdownlint-cli": "^0.23.1",
+    "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": "^0.2.3"
   }
 }

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,

src/structs/AbstractStruct.js

@@ -12,11 +12,6 @@ export class AbstractStruct {
    * @param {number} length
    */
   constructor (id, length) {
-    /**
-     * The uniqe identifier of this struct.
-     * @type {ID}
-     * @readonly
-     */
     this.id = id
     this.length = length
     this.deleted = false
@@ -55,15 +50,11 @@ export class AbstractStructRef {
    * @param {ID} id
    */
   constructor (id) {
+    this.id = id
     /**
      * @type {Array<ID>}
      */
     this._missing = []
-    /**
-     * The uniqe identifier of this type.
-     * @type {ID}
-     */
-    this.id = id
   }
 
   /**

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

@@ -2,7 +2,6 @@
 import {
   AbstractStructRef,
   AbstractStruct,
-  createID,
   addStruct,
   StructStore, Transaction, ID // eslint-disable-line
 } from '../internals.js'
@@ -78,8 +77,7 @@ export class GCRef extends AbstractStructRef {
    */
   toStruct (transaction, store, offset) {
     if (offset > 0) {
-      // @ts-ignore
-      this.id = createID(this.id.client, this.id.clock + offset)
+      this.id.clock += offset
       this.length -= offset
     }
     return new GC(

src/structs/Item.js

@@ -1,10 +1,9 @@
 
 import {
   readID,
-  createID,
   writeID,
   GC,
-  nextID,
+  getState,
   AbstractStructRef,
   AbstractStruct,
   replaceStruct,
@@ -21,6 +20,7 @@ import {
   readContentAny,
   readContentString,
   readContentEmbed,
+  createID,
   readContentFormat,
   readContentType,
   addChangedTypeToTransaction,
@@ -88,12 +88,12 @@ 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,
@@ -116,7 +116,7 @@ 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)
@@ -137,8 +137,12 @@ export const splitItem = (transaction, leftItem, diff) => {
  * @private
  */
 export const redoItem = (transaction, item, redoitems) => {
-  if (item.redone !== null) {
-    return getItemCleanStart(transaction, item.redone)
+  const doc = transaction.doc
+  const store = doc.store
+  const ownClientID = doc.clientID
+  const redone = item.redone
+  if (redone !== null) {
+    return getItemCleanStart(transaction, redone)
   }
   let parentItem = item.parent._item
   /**
@@ -158,7 +162,7 @@ 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
@@ -212,15 +216,17 @@ export const redoItem = (transaction, item, redoitems) => {
       right = right.right
     }
   }
+  const nextClock = getState(store, ownClientID)
+  const nextId = createID(ownClientID, nextClock)
   const redoneItem = new Item(
-    nextID(transaction),
-    left, left === null ? null : left.lastId,
-    right, right === null ? null : right.id,
+    nextId,
+    left, left && left.lastId,
+    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)
   return redoneItem
@@ -294,30 +300,35 @@ export class Item extends AbstractStruct {
      * @type {AbstractContent}
      */
     this.content = content
-    this.length = content.getLength()
-    this.countable = content.isCountable()
     /**
      * If true, do not garbage collect this Item.
      */
     this.keep = false
   }
 
+  get countable () {
+    return this.content.isCountable()
+  }
+
   /**
    * @param {Transaction} transaction
    */
   integrate (transaction) {
     const store = transaction.doc.store
-    const id = this.id
     const parent = this.parent
     const parentSub = this.parentSub
     const length = this.length
+    /**
+     * @type {Item|null}
+     */
+    let left = this.left
     /**
      * @type {Item|null}
      */
     let o
     // set o to the first conflicting item
-    if (this.left !== null) {
-      o = this.left.right
+    if (left !== null) {
+      o = left.right
     } else if (parentSub !== null) {
       o = parent._map.get(parentSub) || null
       while (o !== null && o.left !== null) {
@@ -343,14 +354,14 @@ export class Item extends AbstractStruct {
       conflictingItems.add(o)
       if (compareIDs(this.origin, o.origin)) {
         // case 1
-        if (o.id.client < id.client) {
-          this.left = o
+        if (o.id.client < this.id.client) {
+          left = o
           conflictingItems.clear()
         }
       } else if (o.origin !== null && itemsBeforeOrigin.has(getItem(store, o.origin))) {
         // case 2
         if (o.origin === null || !conflictingItems.has(getItem(store, o.origin))) {
-          this.left = o
+          left = o
           conflictingItems.clear()
         }
       } else {
@@ -358,11 +369,12 @@ 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
+    if (left !== null) {
+      const right = left.right
       this.right = right
-      this.left.right = this
+      left.right = this
     } else {
       let r
       if (parentSub !== null) {
@@ -381,9 +393,9 @@ export class Item extends AbstractStruct {
     } else if (parentSub !== null) {
       // set as current parent value if right === null and this is parentSub
       parent._map.set(parentSub, this)
-      if (this.left !== null) {
+      if (left !== null) {
         // this is the current attribute value of parent. delete right
-        this.left.delete(transaction)
+        left.delete(transaction)
       }
     }
     // adjust length of parent
@@ -522,7 +534,8 @@ export class Item extends AbstractStruct {
     }
     if (origin === null && rightOrigin === null) {
       const parent = 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)
@@ -530,7 +543,7 @@ 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)
@@ -699,10 +712,12 @@ export class ItemRef extends AbstractStructRef {
      */
     this.parentSub = canCopyParentInfo && (info & binary.BIT6) === binary.BIT6 ? decoding.readVarString(decoder) : null
     const missing = this._missing
-    if (this.left !== null) {
+    // Only add items to missing if they don't preceed this item (indicating that it has already been added).
+    // @todo Creating missing items could be done outside this constructor
+    if (this.left !== null && this.left.client !== id.client) {
       missing.push(this.left)
     }
-    if (this.right !== null) {
+    if (this.right !== null && this.right.client !== id.client) {
       missing.push(this.right)
     }
     if (this.parent !== null) {
@@ -723,11 +738,7 @@ export class ItemRef extends AbstractStructRef {
    */
   toStruct (transaction, store, offset) {
     if (offset > 0) {
-      /**
-       * @type {ID}
-       */
-      const id = this.id
-      this.id = createID(id.client, id.clock + offset)
+      this.id.clock += offset
       this.left = createID(this.id.client, this.id.clock - 1)
       this.content = this.content.splice(offset)
       this.length -= offset
@@ -735,10 +746,11 @@ export class ItemRef extends AbstractStructRef {
 
     const left = this.left === null ? null : getItemCleanEnd(transaction, store, this.left)
     const right = this.right === null ? null : getItemCleanStart(transaction, this.right)
+    const parentId = this.parent
     let parent = null
     let parentSub = this.parentSub
-    if (this.parent !== null) {
-      const parentItem = getItem(store, this.parent)
+    if (parentId !== null) {
+      const parentItem = getItem(store, parentId)
       // 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
@@ -767,9 +779,9 @@ export class ItemRef extends AbstractStructRef {
       : new Item(
         this.id,
         left,
-        this.left,
+        left && left.lastId,
         right,
-        this.right,
+        right && right.id,
         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'
@@ -19,6 +19,22 @@ 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).
@@ -359,6 +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>}
@@ -366,7 +385,7 @@ 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)
       jsonContent = []
     }
@@ -385,12 +404,12 @@ 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)
             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)
             } else {
               throw new Error('Unexpected content type in insert operation')
@@ -493,6 +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])
@@ -516,7 +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)
 }
 
 /**

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 () {
@@ -121,6 +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.
    *

src/types/YMap.js

@@ -42,7 +42,7 @@ export class YMapEvent extends YEvent {
  * A shared Map implementation.
  *
  * @extends AbstractType<YMapEvent<T>>
- * @implements {IterableIterator}
+ * @implements {Iterable<T>}
  */
 export class YMap extends AbstractType {
   constructor () {

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
@@ -146,8 +150,10 @@ 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)
   }
   return { left, right }
@@ -211,6 +217,8 @@ const minimizeAttributeChanges = (left, right, currentAttributes, attributes) =>
  * @function
  **/
 const insertAttributes = (transaction, parent, left, right, currentAttributes, attributes) => {
+  const doc = transaction.doc
+  const ownClientId = doc.clientID
   const negatedAttributes = new Map()
   // insert format-start items
   for (const key in attributes) {
@@ -219,7 +227,7 @@ 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))
+      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)
     }
   }
@@ -245,13 +253,15 @@ const insertText = (transaction, parent, left, right, currentAttributes, text, a
       attributes[key] = null
     }
   }
+  const doc = transaction.doc
+  const ownClientId = doc.clientID
   const minPos = minimizeAttributeChanges(left, right, currentAttributes, attributes)
   const insertPos = insertAttributes(transaction, parent, minPos.left, minPos.right, currentAttributes, attributes)
   left = insertPos.left
   right = insertPos.right
   // insert content
   const content = text.constructor === String ? new ContentString(/** @type {string} */ (text)) : new ContentEmbed(text)
-  left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, content)
+  left = new Item(createID(ownClientId, getState(doc.store, ownClientId)), left, left && left.lastId, right, right && right.id, parent, null, content)
   left.integrate(transaction)
   return insertNegatedAttributes(transaction, parent, left, insertPos.right, insertPos.negatedAttributes)
 }
@@ -270,6 +280,8 @@ const insertText = (transaction, parent, left, right, currentAttributes, text, a
  * @function
  */
 const formatText = (transaction, parent, left, right, currentAttributes, length, attributes) => {
+  const doc = transaction.doc
+  const ownClientId = doc.clientID
   const minPos = minimizeAttributeChanges(left, right, currentAttributes, attributes)
   const insertPos = insertAttributes(transaction, parent, minPos.left, minPos.right, currentAttributes, attributes)
   const negatedAttributes = insertPos.negatedAttributes
@@ -314,12 +326,116 @@ 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)
   }
   return insertNegatedAttributes(transaction, parent, left, right, 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} item
+ */
+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 {Item|null} left
@@ -332,6 +448,8 @@ const formatText = (transaction, parent, left, right, currentAttributes, length,
  * @function
  */
 const deleteText = (transaction, left, right, currentAttributes, length) => {
+  const startAttrs = map.copy(currentAttributes)
+  const start = right
   while (length > 0 && right !== null) {
     if (right.deleted === false) {
       switch (right.content.constructor) {
@@ -351,6 +469,9 @@ const deleteText = (transaction, left, right, currentAttributes, length) => {
     left = right
     right = right.right
   }
+  if (start) {
+    cleanupFormattingGap(transaction, start, right, startAttrs, map.copy(currentAttributes))
+  }
   return { left, right }
 }
 
@@ -649,7 +770,48 @@ export class YText extends AbstractType {
    * @param {Set<null|string>} parentSubs Keys changed on this type. `null` if list was modified.
    */
   _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)
   }
 
   /**
@@ -686,10 +848,13 @@ 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 => {
         /**
@@ -705,7 +870,7 @@ 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 && pos.right === null && op.insert.slice(-1) === '\n') ? op.insert.slice(0, -1) : op.insert
             if (typeof ins !== 'string' || ins.length > 0) {
               pos = insertText(transaction, this, pos.left, pos.right, currentAttributes, ins, op.attributes || {})
             }
@@ -916,6 +1081,9 @@ export class YText extends AbstractType {
    * @public
    */
   format (index, length, attributes) {
+    if (length === 0) {
+      return
+    }
     const y = this.doc
     if (y !== null) {
       transact(y, transaction => {

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

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'

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>>}
      */

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)
 }

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'

src/utils/StructStore.js

@@ -2,7 +2,7 @@
 import {
   GC,
   splitItem,
-  GCRef, ItemRef, Transaction, ID, Item // eslint-disable-line
+  AbstractStruct, GCRef, ItemRef, Transaction, ID, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as math from 'lib0/math.js'
@@ -114,7 +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}
  *
@@ -124,10 +124,15 @@ 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 (mid.id.clock === clock) {
+    return right
+  }
+  let midindex = math.floor((clock / (midclock + mid.length)) * right) // pivoting the search
   while (left <= right) {
-    const midindex = math.floor((left + right) / 2)
-    const mid = structs[midindex]
-    const midclock = mid.id.clock
+    mid = structs[midindex]
+    midclock = mid.id.clock
     if (midclock <= clock) {
       if (clock < midclock + mid.length) {
         return midindex
@@ -136,6 +141,7 @@ export const findIndexSS = (structs, clock) => {
     } else {
       right = midindex - 1
     }
+    midindex = math.floor((left + right) / 2)
   }
   // Always check state before looking for a struct in StructStore
   // Therefore the case of not finding a struct is unexpected
@@ -163,16 +169,10 @@ export const find = (store, id) => {
 
 /**
  * Expects that id is actually in store. This function throws or is an infinite loop otherwise.
- *
- * @param {StructStore} store
- * @param {ID} id
- * @return {Item}
- *
  * @private
  * @function
  */
-// @ts-ignore
-export const getItem = (store, id) => find(store, id)
+export const getItem = /** @type {function(StructStore,ID):Item} */ (find)
 
 /**
  * @param {Transaction} transaction

src/utils/Transaction.js

@@ -1,7 +1,6 @@
 
 import {
   getState,
-  createID,
   writeStructsFromTransaction,
   writeDeleteSet,
   DeleteSet,
@@ -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'
 
 /**
@@ -84,9 +86,9 @@ export class Transaction {
      */
     this.changedParentTypes = new Map()
     /**
-     * @type {Set<ID>}
+     * @type {Array<AbstractStruct>}
      */
-    this._mergeStructs = new Set()
+    this._mergeStructs = []
     /**
      * @type {any}
      */
@@ -168,7 +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
@@ -197,7 +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
@@ -233,6 +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)
@@ -290,7 +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--) {
@@ -301,10 +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) {
-        const client = mid.client
-        const clock = mid.clock
-        const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
+      for (let i = 0; i < mergeStructs.length; i++) {
+        const { client, clock } = mergeStructs[i].id
+        const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
         const replacedStructPos = findIndexSS(structs, clock)
         if (replacedStructPos + 1 < structs.length) {
           tryToMergeWithLeft(structs, replacedStructPos + 1)
@@ -313,6 +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')) {

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 {number} len
+   * @param {Map<number,number>} beforeState
+   * @param {Map<number,number>} afterState
    */
-  constructor (ds, start, len) {
+  constructor (ds, beforeState, afterState) {
     this.ds = ds
-    this.start = start
-    this.len = len
+    this.beforeState = beforeState
+    this.afterState = afterState
     /**
      * Use this to save and restore metadata like selection range
      */
@@ -50,27 +50,58 @@ 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))
+      /**
+       * @type {Array<Item>}
+       */
+      const itemsToDelete = []
       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))
+      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 > len) {
+                  getItemCleanStart(transaction, createID(item.id.client, endClock))
+                }
+                struct = item
+              }
+              if (!struct.deleted && scope.some(type => isParentOf(type, /** @type {Item} */ (struct)))) {
+                itemsToDelete.push(struct)
+              }
+            }
+          })
         }
-      }
+      })
       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.
-          !(struct.id.client === clientID && struct.id.clock >= stackStartClock && struct.id.clock < stackEndClock)
+          !(clock >= startClock && clock < endClock)
         ) {
           itemsToRedo.add(struct)
         }
@@ -78,27 +109,6 @@ const popStackItem = (undoManager, stack, eventType) => {
       itemsToRedo.forEach(struct => {
         performedChange = redoItem(transaction, struct, itemsToRedo) !== null || performedChange
       })
-      /**
-       * @type {Array<Item>}
-       */
-      const itemsToDelete = []
-      iterateStructs(transaction, structs, stackStartClock, stackItem.len, struct => {
-        if (struct instanceof Item) {
-          if (struct.redone !== null) {
-            let { item, diff } = followRedone(store, struct.id)
-            if (diff > 0) {
-              item = getItemCleanStart(transaction, createID(item.id.client, item.id.clock + diff))
-            }
-            if (item.length > stackItem.len) {
-              getItemCleanStart(transaction, createID(item.id.client, stackEndClock))
-            }
-            struct = item
-          }
-          if (!struct.deleted && scope.some(type => isParentOf(type, /** @type {Item} */ (struct)))) {
-            itemsToDelete.push(struct)
-          }
-        }
-      })
       // We want to delete in reverse order so that children are deleted before
       // parents, so we have more information available when items are filtered.
       for (let i = itemsToDelete.length - 1; i >= 0; i--) {
@@ -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 afterState = transaction.afterState.get(this.doc.clientID) || 0
+      const beforeState = transaction.beforeState
+      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/encoding.js

@@ -19,15 +19,15 @@ import {
   GCRef,
   ItemRef,
   writeID,
-  createID,
   readID,
   getState,
+  createID,
   getStateVector,
   readAndApplyDeleteSet,
   writeDeleteSet,
   createDeleteSetFromStructStore,
   transact,
-  Doc, Transaction, AbstractStruct, StructStore, ID // eslint-disable-line
+  Doc, Transaction, GC, Item, StructStore, ID // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -36,7 +36,7 @@ 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 +50,12 @@ 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
@@ -111,22 +88,30 @@ export const writeClientsStructs = (encoder, store, _sm) => {
 
 /**
  * @param {decoding.Decoder} decoder The decoder object to read data from.
+ * @param {Map<number,Array<GCRef|ItemRef>>} clientRefs
  * @return {Map<number,Array<GCRef|ItemRef>>}
  *
  * @private
  * @function
  */
-export const readClientsStructRefs = decoder => {
-  /**
-   * @type {Map<number,Array<GCRef|ItemRef>>}
-   */
-  const clientRefs = new Map()
+export const readClientsStructRefs = (decoder, clientRefs) => {
   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)
-    clientRefs.set(nextID.client, refs)
+    const nextIdClient = nextID.client
+    let nextIdClock = nextID.clock
+    /**
+     * @type {Array<GCRef|ItemRef>}
+     */
+    const refs = []
+    clientRefs.set(nextIdClient, refs)
+    for (let i = 0; i < numberOfStructs; i++) {
+      const info = decoding.readUint8(decoder)
+      const ref = (binary.BITS5 & info) === 0 ? new GCRef(decoder, createID(nextIdClient, nextIdClock), info) : new ItemRef(decoder, createID(nextIdClient, nextIdClock), info)
+      refs.push(ref)
+      nextIdClock += ref.length
+    }
   }
   return clientRefs
 }
@@ -171,16 +156,18 @@ const resumeStructIntegration = (transaction, store) => {
     }
     const ref = stack[stack.length - 1]
     const m = ref._missing
-    const client = ref.id.client
+    const refID = ref.id
+    const client = refID.client
+    const refClock = refID.clock
     const localClock = getState(store, client)
-    const offset = ref.id.clock < localClock ? localClock - ref.id.clock : 0
-    if (ref.id.clock + offset !== localClock) {
+    const offset = refClock < localClock ? localClock - refClock : 0
+    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)
       if (structRefs !== undefined) {
         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
@@ -282,7 +269,8 @@ const mergeReadStructsIntoPendingReads = (store, clientsStructsRefs) => {
  * @function
  */
 export const readStructs = (decoder, transaction, store) => {
-  const clientsStructRefs = readClientsStructRefs(decoder)
+  const clientsStructRefs = new Map()
+  readClientsStructRefs(decoder, clientsStructRefs)
   mergeReadStructsIntoPendingReads(store, clientsStructRefs)
   resumeStructIntegration(transaction, store)
   tryResumePendingDeleteReaders(transaction, store)

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-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
 
 /**
@@ -180,3 +183,206 @@ export const testToDeltaEmbedNoAttributes = tc => {
   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)
+}
+
+/**
+ * @param {t.TestCase} tc
+ *
+export const testLargeFragmentedDocument = tc => {
+  const { text0, text1, testConnector } = init(tc, { users: 2 })
+  // @ts-ignore
+  text0.doc.transact(() => {
+    for (let i = 0; i < 1000000; i++) {
+      text0.insert(0, '0')
+    }
+  })
+  t.measureTime('time to apply', () => {
+    testConnector.flushAllMessages()
+  })
+}
+*/
+
+// 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))
+}