13.6.17

Readme fixes

INTERNALS.md

@@ -26,7 +26,7 @@ article](https://blog.kevinjahns.de/are-crdts-suitable-for-shared-editing/).
 
 Each client is assigned a unique *clientID* property on first insert. This is a
 random 53-bit integer (53 bits because that fits in the javascript safe integer
-range).
+range \[JavaScript uses IEEE 754 floats\]).
 
 ## List items
 
@@ -88,7 +88,7 @@ When a local insert happens, Yjs needs to map the insert position in the
 document (eg position 1000) to an ID. With just the linked list, this would
 require a slow O(n) linear scan of the list. But when editing a document, most
 inserts are either at the same position as the last insert, or nearby. To
-improve performance, Yjs stores a cache of the 10 most recently looked up
+improve performance, Yjs stores a cache of the 80 most recently looked up
 insert positions in the document. This is consulted and updated when a position
 is looked up to improve performance in the average case. The cache is updated
 using a heuristic that is still changing (currently, it is updated when a new

README.md

@@ -49,12 +49,16 @@ Showcase](https://yjs-diagram.synergy.codes/).
 ## Who is using Yjs
 
 * [AFFiNE](https://affine.pro/) A local-first, privacy-first, open source
-  knowledge base. 🏅
+  knowledge base. :star2:
+* [Huly](https://huly.io/) - Open Source All-in-One Project Management Platform :star2:
 * [Cargo](https://cargo.site/) Site builder for designers and artists :star2:
 * [Gitbook](https://gitbook.com) Knowledge management for technical teams :star2:
 * [Evernote](https://evernote.com) Note-taking app :star2:
 * [Lessonspace](https://thelessonspace.com) Enterprise platform for virtual
   classrooms and online training :star2:
+* [Ellipsus](ellipsus.com) - Collaborative writing app for storytelling etc.
+  Supports versioning, change attribution, and "blame". A solution for the whole
+  publishing process (also selling) :star:
 * [Dynaboard](https://dynaboard.com/) Build web apps collaboratively. :star:
 * [Relm](https://www.relm.us/) A collaborative gameworld for teamwork and
   community. :star:
@@ -64,11 +68,15 @@ Showcase](https://yjs-diagram.synergy.codes/).
   Nimbus Web. :star:
 * [Pluxbox RadioManager](https://getradiomanager.com/) A web-based app to
   collaboratively organize radio broadcasts. :star:
+* [modyfi](https://www.modyfi.com) - Modyfi is the design platform built for
+  multidisciplinary designers. Design, generate, animate, and more — without
+  switching between apps. :star:
 * [Sana](https://sanalabs.com/) A learning platform with collaborative text
   editing powered by Yjs.
 * [Serenity Notes](https://www.serenity.re/en/notes) End-to-end encrypted
   collaborative notes app.
-* [PRSM](https://prsm.uk/) Collaborative mind-mapping and system visualisation. *[(source)](https://github.com/micrology/prsm)*
+* [PRSM](https://prsm.uk/) Collaborative mind-mapping and system visualisation.
+  *[(source)](https://github.com/micrology/prsm)*
 * [Alldone](https://alldone.app/) A next-gen project management and
   collaboration platform.
 * [Living Spec](https://livingspec.com/) A modern way for product teams to collaborate.
@@ -91,6 +99,21 @@ Showcase](https://yjs-diagram.synergy.codes/).
 * [AWS SageMaker](https://aws.amazon.com/sagemaker/) Tools for building Machine
   Learning Models
 * [linear](https://linear.app) Streamline issues, projects, and product roadmaps.
+* [btw](https://www.btw.so) - Personal website builder
+* [AWS SageMaker](https://aws.amazon.com/sagemaker/) - Machine Learning Service
+* [Arkiter](https://www.arkiter.com/) - Live interview software
+* [Appflowy](https://www.appflowy.io/) - They use Yrs
+* [Multi.app](https://multi.app) - Multiplayer app sharing: Point, draw and edit
+  in shared apps as if they're on your computer. They are using Yrs.
+* [AppMaster](https://appmaster.io) A No-Code platform for creating
+  production-ready applications with source code generation.
+* [Synthesia](https://www.synthesia.io) - Collaborative Video Editor
+* [thinkdeli](https://thinkdeli.com) - A fast and simple notes app powered by AI
+* [ourboard](https://github.com/raimohanska/ourboard) - A collaborative whiteboard
+  applicaiton
+* [Ellie.ai](https://ellie.ai) - Data Product Design and Collaboration
+* [GoPeer](https://gopeer.org/) - Collaborative tutoring
+* [screen.garden](https://screen.garden) Collaborative backend for PKM apps.
 
 ## Table of Contents
 
@@ -145,9 +168,10 @@ collaborative app.
   <dt><a href="https://github.com/yjs/y-websocket">y-websocket</a></dt>
   <dd>
 A module that contains a simple websocket backend and a websocket client that
-connects to that backend. The backend can be extended to persist updates in a
-leveldb database. <b>y-sweet</b> and <b>ypy-websocket</b> (see below) are
-compatible to the y-wesocket protocol.
+connects to that backend. <a href="https://github.com/yjs/y-redis/"><b>y-redis</b></a>,
+<b>y-sweet</b>, <b>ypy-websocket</b> and <a href="https://tiptap.dev/docs/hocuspocus/introduction">
+<b>Hocuspocus</b></a> (see below) are alternative
+backends to y-websocket.
   </dd>
   <dt><a href="https://github.com/yjs/y-webrtc">y-webrtc</a></dt>
   <dd>
@@ -169,6 +193,10 @@ browser DevTools extension.
   <dd>
 A standalone yjs server with persistence to S3 or filesystem. They offer a
 <a href="https://y-sweet.cloud">cloud service</a> as well.
+  </dd>
+  <dt><a href="https://github.com/ueberdosis/hocuspocus">Hocuspocus</a></dt>
+  <dd>
+A standalone extensible yjs server with sqlite persistence, webhooks, auth and more.
   </dd>
   <dt><a href="https://docs.partykit.io/reference/y-partykit-api/">PartyKit</a></dt>
   <dd>
@@ -205,6 +233,15 @@ An ActionCable companion for Yjs clients. There is a fitting
   <dd>
 Websocket backend, written in Python.
   </dd>
+  <dt><a href="https://tinybase.org/">Tinybase</a></dt>
+  <dd>
+The reactive data store for local-first apps. They support multiple CRDTs and
+    different network technologies.
+  </dd>
+  <dt><a href="https://codeberg.org/webxdc/y-webxdc">y-webxdc</a></dt>
+  <dd>
+Provider for sharing data in <a href="https://webxdc.org">webxdc chat apps</a>.
+  </dd>
 </dl>
 
 #### Persistence Providers
@@ -230,6 +267,17 @@ Like y-indexeddb, but with sub-documents support and fully TypeScript.
   <dd>
 A database and connection provider for Yjs based on Firestore.
   </dd>
+  <dt><a href="https://github.com/malte-j/y-op-sqlite">y-op-sqlite</a></dt>
+  <dd>
+  Persist YJS updates in your React Native app using
+   <a href="https://github.com/OP-Engineering/op-sqlite">op-sqlite</a>
+  , the fastest SQLite library for React Native.  
+  </dd>
+  <dt><a href="https://github.com/MaxNoetzold/y-postgresql">y-postgresql</a></dt>
+  <dd>
+  Provides persistent storage for a web server using PostgreSQL and
+  is easily compatible with y-websocket.  
+  </dd>
 </dl>
 
 # Ports
@@ -259,7 +307,7 @@ 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

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "yjs",
-  "version": "13.6.14",
+  "version": "13.6.17",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "yjs",
-      "version": "13.6.14",
+      "version": "13.6.17",
       "license": "MIT",
       "dependencies": {
         "lib0": "^0.2.86"

package.json

@@ -1,6 +1,6 @@
 {
   "name": "yjs",
-  "version": "13.6.14",
+  "version": "13.6.17",
   "description": "Shared Editing Library",
   "main": "./dist/yjs.cjs",
   "module": "./dist/yjs.mjs",

src/index.js

@@ -100,6 +100,7 @@ export {
   UpdateDecoderV1,
   UpdateDecoderV2,
   equalDeleteSets,
+  mergeDeleteSets,
   snapshotContainsUpdate
 } from './internals.js'
 

src/types/AbstractType.js

@@ -316,6 +316,10 @@ export class AbstractType {
   }
 
   /**
+   * Makes a copy of this data type that can be included somewhere else.
+   *
+   * Note that the content is only readable _after_ it has been included somewhere in the Ydoc.
+   *
    * @return {AbstractType<EventType>}
    */
   clone () {
@@ -477,7 +481,7 @@ export const typeListToArraySnapshot = (type, snapshot) => {
 }
 
 /**
- * Executes a provided function on once on overy element of this YArray.
+ * Executes a provided function on once on every element of this YArray.
  *
  * @param {AbstractType<any>} type
  * @param {function(any,number,any):void} f A function to execute on every element of this YArray.
@@ -569,7 +573,7 @@ export const typeListCreateIterator = type => {
 }
 
 /**
- * Executes a provided function on once on overy element of this YArray.
+ * Executes a provided function on once on every element of this YArray.
  * Operates on a snapshotted state of the document.
  *
  * @param {AbstractType<any>} type

src/types/YArray.js

@@ -25,16 +25,7 @@ import { typeListSlice } from './AbstractType.js'
  * @template T
  * @extends YEvent<YArray<T>>
  */
-export class YArrayEvent extends YEvent {
-  /**
-   * @param {YArray<T>} yarray The changed type
-   * @param {Transaction} transaction The transaction object
-   */
-  constructor (yarray, transaction) {
-    super(yarray, transaction)
-    this._transaction = transaction
-  }
-}
+export class YArrayEvent extends YEvent {}
 
 /**
  * A shared Array implementation.
@@ -95,6 +86,10 @@ export class YArray extends AbstractType {
   }
 
   /**
+   * Makes a copy of this data type that can be included somewhere else.
+   *
+   * Note that the content is only readable _after_ it has been included somewhere in the Ydoc.
+   *
    * @return {YArray<T>}
    */
   clone () {
@@ -167,9 +162,9 @@ export class YArray extends AbstractType {
   }
 
   /**
-   * Preppends content to this YArray.
+   * Prepends content to this YArray.
    *
-   * @param {Array<T>} content Array of content to preppend.
+   * @param {Array<T>} content Array of content to prepend.
    */
   unshift (content) {
     this.insert(0, content)
@@ -211,7 +206,8 @@ export class YArray extends AbstractType {
   }
 
   /**
-   * Transforms this YArray to a JavaScript Array.
+   * Returns a portion of this YArray into a JavaScript Array selected
+   * from start to end (end not included).
    *
    * @param {number} [start]
    * @param {number} [end]
@@ -244,7 +240,7 @@ export class YArray extends AbstractType {
   }
 
   /**
-   * Executes a provided function once on overy element of this YArray.
+   * Executes a provided function once on every element of this YArray.
    *
    * @param {function(T,number,YArray<T>):void} f A function to execute on every element of this YArray.
    */

src/types/YMap.js

@@ -88,6 +88,10 @@ export class YMap extends AbstractType {
   }
 
   /**
+   * Makes a copy of this data type that can be included somewhere else.
+   *
+   * Note that the content is only readable _after_ it has been included somewhere in the Ydoc.
+   *
    * @return {YMap<MapType>}
    */
   clone () {

src/types/YText.js

@@ -897,6 +897,10 @@ export class YText extends AbstractType {
   }
 
   /**
+   * Makes a copy of this data type that can be included somewhere else.
+   *
+   * Note that the content is only readable _after_ it has been included somewhere in the Ydoc.
+   *
    * @return {YText}
    */
   clone () {

src/types/YXmlElement.js

@@ -81,6 +81,10 @@ export class YXmlElement extends YXmlFragment {
   }
 
   /**
+   * Makes a copy of this data type that can be included somewhere else.
+   *
+   * Note that the content is only readable _after_ it has been included somewhere in the Ydoc.
+   *
    * @return {YXmlElement<KV>}
    */
   clone () {

src/types/YXmlFragment.js

@@ -163,6 +163,10 @@ export class YXmlFragment extends AbstractType {
   }
 
   /**
+   * Makes a copy of this data type that can be included somewhere else.
+   *
+   * Note that the content is only readable _after_ it has been included somewhere in the Ydoc.
+   *
    * @return {YXmlFragment}
    */
   clone () {
@@ -376,9 +380,9 @@ export class YXmlFragment extends AbstractType {
   }
 
   /**
-   * Preppends content to this YArray.
+   * Prepends content to this YArray.
    *
-   * @param {Array<YXmlElement|YXmlText>} content Array of content to preppend.
+   * @param {Array<YXmlElement|YXmlText>} content Array of content to prepend.
    */
   unshift (content) {
     this.insert(0, content)
@@ -395,7 +399,8 @@ export class YXmlFragment extends AbstractType {
   }
 
   /**
-   * Transforms this YArray to a JavaScript Array.
+   * Returns a portion of this YXmlFragment into a JavaScript Array selected
+   * from start to end (end not included).
    *
    * @param {number} [start]
    * @param {number} [end]
@@ -406,7 +411,7 @@ export class YXmlFragment extends AbstractType {
   }
 
   /**
-   * Executes a provided function on once on overy child element.
+   * Executes a provided function on once on every child element.
    *
    * @param {function(YXmlElement|YXmlText,number, typeof self):void} f A function to execute on every element of this YArray.
    */

src/types/YXmlHook.js

@@ -29,6 +29,10 @@ export class YXmlHook extends YMap {
   }
 
   /**
+   * Makes a copy of this data type that can be included somewhere else.
+   *
+   * Note that the content is only readable _after_ it has been included somewhere in the Ydoc.
+   *
    * @return {YXmlHook}
    */
   clone () {

src/types/YXmlText.js

@@ -30,6 +30,10 @@ export class YXmlText extends YText {
   }
 
   /**
+   * Makes a copy of this data type that can be included somewhere else.
+   *
+   * Note that the content is only readable _after_ it has been included somewhere in the Ydoc.
+   *
    * @return {YXmlText}
    */
   clone () {

src/utils/Doc.js

@@ -187,22 +187,22 @@ export class Doc extends ObservableV2 {
   /**
    * Define a shared data type.
    *
-   * Multiple calls of `y.get(name, TypeConstructor)` yield the same result
+   * Multiple calls of `ydoc.get(name, TypeConstructor)` yield the same result
    * and do not overwrite each other. I.e.
-   * `y.define(name, Y.Array) === y.define(name, Y.Array)`
+   * `ydoc.get(name, Y.Array) === ydoc.get(name, Y.Array)`
    *
-   * After this method is called, the type is also available on `y.share.get(name)`.
+   * After this method is called, the type is also available on `ydoc.share.get(name)`.
    *
    * *Best Practices:*
-   * Define all types right after the Yjs instance is created and store them in a separate object.
+   * Define all types right after the Y.Doc instance is created and store them in a separate object.
    * Also use the typed methods `getText(name)`, `getArray(name)`, ..
    *
    * @template {typeof AbstractType<any>} Type
    * @example
-   *   const y = new Y(..)
+   *   const ydoc = new Y.Doc(..)
    *   const appState = {
-   *     document: y.getText('document')
-   *     comments: y.getArray('comments')
+   *     document: ydoc.getText('document')
+   *     comments: ydoc.getArray('comments')
    *   }
    *
    * @param {string} name

src/utils/RelativePosition.js

@@ -8,6 +8,7 @@ import {
   createID,
   ContentType,
   followRedone,
+  getItem,
   ID, Doc, AbstractType // eslint-disable-line
 } from '../internals.js'
 
@@ -101,7 +102,7 @@ export const relativePositionToJSON = rpos => {
  *
  * @function
  */
-export const createRelativePositionFromJSON = json => new RelativePosition(json.type == null ? null : createID(json.type.client, json.type.clock), json.tname || null, json.item == null ? null : createID(json.item.client, json.item.clock), json.assoc == null ? 0 : json.assoc)
+export const createRelativePositionFromJSON = json => new RelativePosition(json.type == null ? null : createID(json.type.client, json.type.clock), json.tname ?? null, json.item == null ? null : createID(json.item.client, json.item.clock), json.assoc == null ? 0 : json.assoc)
 
 export class AbsolutePosition {
   /**
@@ -256,13 +257,24 @@ export const readRelativePosition = decoder => {
 export const decodeRelativePosition = uint8Array => readRelativePosition(decoding.createDecoder(uint8Array))
 
 /**
+ * Transform a relative position to an absolute position.
+ *
+ * If you want to share the relative position with other users, you should set
+ * `followUndoneDeletions` to false to get consistent results across all clients.
+ *
+ * When calculating the absolute position, we try to follow the "undone deletions". This yields
+ * better results for the user who performed undo. However, only the user who performed the undo
+ * will get the better results, the other users don't know which operations recreated a deleted
+ * range of content. There is more information in this ticket: https://github.com/yjs/yjs/issues/638
+ *
  * @param {RelativePosition} rpos
  * @param {Doc} doc
+ * @param {boolean} followUndoneDeletions - whether to follow undone deletions - see https://github.com/yjs/yjs/issues/638
  * @return {AbsolutePosition|null}
  *
  * @function
  */
-export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
+export const createAbsolutePositionFromRelativePosition = (rpos, doc, followUndoneDeletions = true) => {
   const store = doc.store
   const rightID = rpos.item
   const typeID = rpos.type
@@ -274,7 +286,7 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
     if (getState(store, rightID.client) <= rightID.clock) {
       return null
     }
-    const res = followRedone(store, rightID)
+    const res = followUndoneDeletions ? followRedone(store, rightID) : { item: getItem(store, rightID), diff: 0 }
     const right = res.item
     if (!(right instanceof Item)) {
       return null
@@ -298,7 +310,7 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
         // type does not exist yet
         return null
       }
-      const { item } = followRedone(store, typeID)
+      const { item } = followUndoneDeletions ? followRedone(store, typeID) : { item: getItem(store, typeID) }
       if (item instanceof Item && item.content instanceof ContentType) {
         type = item.content.type
       } else {

src/utils/Transaction.js

@@ -28,7 +28,8 @@ import { callAll } from 'lib0/function'
  * possible. Here is an example to illustrate the advantages of bundling:
  *
  * @example
- * const map = y.define('map', YMap)
+ * const ydoc = new Y.Doc()
+ * const map = ydoc.getMap('map')
  * // Log content when change is triggered
  * map.observe(() => {
  *   console.log('change triggered')
@@ -37,7 +38,7 @@ import { callAll } from 'lib0/function'
  * map.set('a', 0) // => "change triggered"
  * map.set('b', 0) // => "change triggered"
  * // When put in a transaction, it will trigger the log after the transaction:
- * y.transact(() => {
+ * ydoc.transact(() => {
  *   map.set('a', 1)
  *   map.set('b', 1)
  * }) // => "change triggered"
@@ -224,7 +225,7 @@ const tryGcDeleteSet = (ds, store, gcFilter) => {
  */
 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
+  // merge from right to left for better efficiency and so we don't miss any merge targets
   ds.clients.forEach((deleteItems, client) => {
     const structs = /** @type {Array<GC|Item>} */ (store.clients.get(client))
     for (let di = deleteItems.length - 1; di >= 0; di--) {

src/utils/YEvent.js

@@ -264,8 +264,8 @@ const getPathTo = (parent, child) => {
       let i = 0
       let c = /** @type {AbstractType<any>} */ (child._item.parent)._start
       while (c !== child._item && c !== null) {
-        if (!c.deleted) {
-          i++
+        if (!c.deleted && c.countable) {
+          i += c.length
         }
         c = c.right
       }

src/utils/encoding.js

@@ -154,7 +154,7 @@ export const readClientsStructRefs = (decoder, doc) => {
           // @type {string|null}
           const struct = new Item(
             createID(client, clock),
-            null, // leftd
+            null, // left
             (info & binary.BIT8) === binary.BIT8 ? decoder.readLeftID() : null, // origin
             null, // right
             (info & binary.BIT7) === binary.BIT7 ? decoder.readRightID() : null, // right origin
@@ -178,7 +178,7 @@ export const readClientsStructRefs = (decoder, doc) => {
 
           const struct = new Item(
             createID(client, clock),
-            null, // leftd
+            null, // left
             origin, // origin
             null, // right
             rightOrigin, // right origin
@@ -370,7 +370,7 @@ export const writeStructsFromTransaction = (encoder, transaction) => writeClient
 /**
  * Read and apply a document update.
  *
- * This function has the same effect as `applyUpdate` but accepts an decoder.
+ * This function has the same effect as `applyUpdate` but accepts a decoder.
  *
  * @param {decoding.Decoder} decoder
  * @param {Doc} ydoc
@@ -451,7 +451,7 @@ export const readUpdateV2 = (decoder, ydoc, transactionOrigin, structDecoder = n
 /**
  * Read and apply a document update.
  *
- * This function has the same effect as `applyUpdate` but accepts an decoder.
+ * This function has the same effect as `applyUpdate` but accepts a decoder.
  *
  * @param {decoding.Decoder} decoder
  * @param {Doc} ydoc

tests/relativePositions.tests.js

@@ -101,3 +101,25 @@ export const testRelativePositionAssociationDifference = tc => {
   t.assert(posRight != null && posRight.index === 2)
   t.assert(posLeft != null && posLeft.index === 1)
 }
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testRelativePositionWithUndo = tc => {
+  const ydoc = new Y.Doc()
+  const ytext = ydoc.getText()
+  ytext.insert(0, 'hello world')
+  const rpos = Y.createRelativePositionFromTypeIndex(ytext, 1)
+  const um = new Y.UndoManager(ytext)
+  ytext.delete(0, 6)
+  t.assert(Y.createAbsolutePositionFromRelativePosition(rpos, ydoc)?.index === 0)
+  um.undo()
+  t.assert(Y.createAbsolutePositionFromRelativePosition(rpos, ydoc)?.index === 1)
+  const posWithoutFollow = Y.createAbsolutePositionFromRelativePosition(rpos, ydoc, false)
+  console.log({ posWithoutFollow })
+  t.assert(Y.createAbsolutePositionFromRelativePosition(rpos, ydoc, false)?.index === 6)
+  const ydocClone = new Y.Doc()
+  Y.applyUpdate(ydocClone, Y.encodeStateAsUpdate(ydoc))
+  t.assert(Y.createAbsolutePositionFromRelativePosition(rpos, ydocClone)?.index === 6)
+  t.assert(Y.createAbsolutePositionFromRelativePosition(rpos, ydocClone, false)?.index === 6)
+}

tests/y-array.tests.js

@@ -330,6 +330,29 @@ export const testObserveDeepEventOrder = tc => {
   }
 }
 
+/**
+ * Correct index when computing event.path in observeDeep - https://github.com/yjs/yjs/issues/457
+ *
+ * @param {t.TestCase} _tc
+ */
+export const testObservedeepIndexes = _tc => {
+  const doc = new Y.Doc()
+  const map = doc.getMap()
+  // Create a field with the array as value
+  map.set('my-array', new Y.Array())
+  // Fill the array with some strings and our Map
+  map.get('my-array').push(['a', 'b', 'c', new Y.Map()])
+  /**
+   * @type {Array<any>}
+   */
+  let eventPath = []
+  map.observeDeep((events) => { eventPath = events[0].path })
+  // set a value on the map inside of our array
+  map.get('my-array').get(3).set('hello', 'world')
+  console.log(eventPath)
+  t.compare(eventPath, ['my-array', 3])
+}
+
 /**
  * @param {t.TestCase} tc
  */

tests/y-text.tests.js

@@ -1746,6 +1746,27 @@ export const testBasicFormat = tc => {
   compare(users)
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testFalsyFormats = tc => {
+  const { users, text0 } = init(tc, { users: 2 })
+  let delta
+  text0.observe(event => {
+    delta = event.delta
+  })
+  text0.insert(0, 'abcde', { falsy: false })
+  t.compare(text0.toDelta(), [{ insert: 'abcde', attributes: { falsy: false } }])
+  t.compare(delta, [{ insert: 'abcde', attributes: { falsy: false } }])
+  text0.format(1, 3, { falsy: true })
+  t.compare(text0.toDelta(), [{ insert: 'a', attributes: { falsy: false } }, { insert: 'bcd', attributes: { falsy: true } }, { insert: 'e', attributes: { falsy: false } }])
+  t.compare(delta, [{ retain: 1 }, { retain: 3, attributes: { falsy: true } }])
+  text0.format(2, 1, { falsy: false })
+  t.compare(text0.toDelta(), [{ insert: 'a', attributes: { falsy: false } }, { insert: 'b', attributes: { falsy: true } }, { insert: 'c', attributes: { falsy: false } }, { insert: 'd', attributes: { falsy: true } }, { insert: 'e', attributes: { falsy: false } }])
+  t.compare(delta, [{ retain: 2 }, { retain: 1, attributes: { falsy: false } }])
+  compare(users)
+}
+
 /**
  * @param {t.TestCase} _tc
  */