Use generic Item with typed content to reduce cache misses

package.json

@@ -13,7 +13,7 @@
     "lint": "standard && tsc",
     "docs": "rm -rf docs; jsdoc --configure ./.jsdoc.json --verbose --readme ./README.v13.md --package ./package.json || true",
     "serve-docs": "npm run docs && serve ./docs/",
-    "preversion": "PRODUCTION=1 npm run dist && npm run docs && node ./dist/tests.js --repitition-time 1000",
+    "preversion": "npm run lint && PRODUCTION=1 npm run dist && npm run docs && node ./dist/tests.js --repitition-time 1000",
     "postversion": "git push && git push --tags",
     "debug": "concurrently 'live-server --port=3443 --entry-file=test.html' 'npm run watch'",
     "trace-deopt": "clear && rollup -c  && node --trace-deopt dist/test.js",
@@ -59,9 +59,7 @@
     "live-server": "^1.2.1",
     "rollup": "^1.11.3",
     "rollup-cli": "^1.0.9",
-    "rollup-plugin-commonjs": "^9.3.4",
     "rollup-plugin-node-resolve": "^4.2.4",
-    "rollup-plugin-terser": "^4.0.4",
     "standard": "^11.0.1",
     "tui-jsdoc-template": "^1.2.2",
     "typescript": "^3.4.5",

rollup.config.js

@@ -1,6 +1,6 @@
 import nodeResolve from 'rollup-plugin-node-resolve'
-import commonjs from 'rollup-plugin-commonjs'
+
-import { terser } from 'rollup-plugin-terser'
+const localImports = process.env.LOCALIMPORTS
 
 const customModules = new Set([
   'y-websocket',
@@ -23,33 +23,18 @@ const debugResolve = {
     if (importee === 'yjs') {
       return `${process.cwd()}/src/index.js`
     }
-    /*
+    if (localImports) {
       if (customModules.has(importee.split('/')[0])) {
         return `${process.cwd()}/../${importee}/src/${importee}.js`
       }
       if (customLibModules.has(importee.split('/')[0])) {
         return `${process.cwd()}/../${importee}`
       }
-    */
+    }
     return null
   }
 }
 
-const minificationPlugins = process.env.PRODUCTION ? [terser({
-  module: true,
-  compress: {
-    hoist_vars: true,
-    module: true,
-    passes: 5,
-    pure_getters: true,
-    unsafe_comps: true,
-    unsafe_undefined: true
-  },
-  mangle: {
-    toplevel: true
-  }
-})] : []
-
 export default [{
   input: './src/index.js',
   output: [{
@@ -84,6 +69,5 @@ export default [{
       sourcemap: true,
       mainFields: ['module', 'browser', 'main']
     })
-    // commonjs()
   ]
 }]

src/index.js

@@ -13,16 +13,16 @@ export {
   YMapEvent,
   YArrayEvent,
   YEvent,
-  AbstractItem,
+  Item,
   AbstractStruct,
   GC,
-  ItemBinary,
+  ContentBinary,
-  ItemDeleted,
+  ContentDeleted,
-  ItemEmbed,
+  ContentEmbed,
-  ItemFormat,
+  ContentFormat,
-  ItemJSON,
+  ContentJSON,
-  ItemString,
+  ContentString,
-  ItemType,
+  ContentType,
   AbstractType,
   RelativePosition,
   createRelativePositionFromTypeIndex,

src/internals.js

@@ -21,14 +21,14 @@ export * from './types/YXmlHook.js'
 export * from './types/YXmlText.js'
 
 export * from './structs/AbstractStruct.js'
-export * from './structs/AbstractItem.js'
 export * from './structs/GC.js'
-export * from './structs/ItemBinary.js'
+export * from './structs/ContentBinary.js'
-export * from './structs/ItemDeleted.js'
+export * from './structs/ContentDeleted.js'
-export * from './structs/ItemEmbed.js'
+export * from './structs/ContentEmbed.js'
-export * from './structs/ItemFormat.js'
+export * from './structs/ContentFormat.js'
-export * from './structs/ItemJSON.js'
+export * from './structs/ContentJSON.js'
-export * from './structs/ItemString.js'
+export * from './structs/ContentString.js'
-export * from './structs/ItemType.js'
+export * from './structs/ContentType.js'
+export * from './structs/Item.js'
 
 export * from './utils/encoding.js'

src/structs/AbstractStruct.js

@@ -12,14 +12,16 @@ import * as error from 'lib0/error.js'
 export class AbstractStruct {
   /**
    * @param {ID} id
+   * @param {number} length
    */
-  constructor (id) {
+  constructor (id, length) {
     /**
      * The uniqe identifier of this struct.
      * @type {ID}
      * @readonly
      */
     this.id = id
+    this.length = length
     this.deleted = false
   }
   /**
@@ -32,12 +34,6 @@ export class AbstractStruct {
   mergeWith (right) {
     return false
   }
-  /**
-   * @type {number}
-   */
-  get length () {
-    throw error.methodUnimplemented()
-  }
   /**
    * @param {encoding.Encoder} encoder The encoder to write data to.
    * @param {number} offset
@@ -89,10 +85,4 @@ export class AbstractStructRef {
   toStruct (transaction, store, offset) {
     throw error.methodUnimplemented()
   }
-  /**
-   * @type {number}
-   */
-  get length () {
-    return 1
-  }
 }

src/structs/ContentBinary.js

@@ -0,0 +1,92 @@
+import {
+  StructStore, Item, Transaction // eslint-disable-line
+} from '../internals.js'
+
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+import * as buffer from 'lib0/buffer.js'
+import * as error from 'lib0/error.js'
+
+/**
+ * @private
+ */
+export class ContentBinary {
+  /**
+   * @param {Uint8Array} content
+   */
+  constructor (content) {
+    this.content = content
+  }
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return 1
+  }
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return [this.content]
+  }
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+  /**
+   * @return {ContentBinary}
+   */
+  copy () {
+    return new ContentBinary(this.content)
+  }
+  /**
+   * @param {number} offset
+   * @return {ContentBinary}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {ContentBinary} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    return false
+  }
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarUint8Array(encoder, this.content)
+  }
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 3
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentBinary}
+ */
+export const readContentBinary = decoder => new ContentBinary(buffer.copyUint8Array(decoding.readVarUint8Array(decoder)))

src/structs/ContentDeleted.js

@@ -0,0 +1,98 @@
+
+import {
+  addToDeleteSet,
+  StructStore, Item, Transaction // eslint-disable-line
+} from '../internals.js'
+
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+
+/**
+ * @private
+ */
+export class ContentDeleted {
+  /**
+   * @param {number} len
+   */
+  constructor (len) {
+    this.len = len
+  }
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return this.len
+  }
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return []
+  }
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return false
+  }
+  /**
+   * @return {ContentDeleted}
+   */
+  copy () {
+    return new ContentDeleted(this.len)
+  }
+  /**
+   * @param {number} offset
+   * @return {ContentDeleted}
+   */
+  splice (offset) {
+    const right = new ContentDeleted(this.len - offset)
+    this.len = offset
+    return right
+  }
+  /**
+   * @param {ContentDeleted} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    this.len += right.len
+    return true
+  }
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {
+    addToDeleteSet(transaction.deleteSet, item.id, this.len)
+    item.deleted = true
+  }
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarUint(encoder, this.len - offset)
+  }
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 1
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentDeleted}
+ */
+export const readContentDeleted = decoder => new ContentDeleted(decoding.readVarUint(decoder))

src/structs/ContentEmbed.js

@@ -0,0 +1,92 @@
+
+import {
+  StructStore, Item, Transaction // eslint-disable-line
+} from '../internals.js'
+
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+import * as error from 'lib0/error.js'
+
+/**
+ * @private
+ */
+export class ContentEmbed {
+  /**
+   * @param {Object} embed
+   */
+  constructor (embed) {
+    this.embed = embed
+  }
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return 1
+  }
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return [this.embed]
+  }
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+  /**
+   * @return {ContentEmbed}
+   */
+  copy () {
+    return new ContentEmbed(this.embed)
+  }
+  /**
+   * @param {number} offset
+   * @return {ContentEmbed}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {ContentEmbed} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    return false
+  }
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarString(encoder, JSON.stringify(this.embed))
+  }
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 5
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentEmbed}
+ */
+export const readContentEmbed = decoder => new ContentEmbed(JSON.parse(decoding.readVarString(decoder)))

src/structs/ContentFormat.js

@@ -0,0 +1,95 @@
+
+import {
+  Item, StructStore, Transaction // eslint-disable-line
+} from '../internals.js'
+
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+import * as error from 'lib0/error.js'
+
+/**
+ * @private
+ */
+export class ContentFormat {
+  /**
+   * @param {string} key
+   * @param {Object} value
+   */
+  constructor (key, value) {
+    this.key = key
+    this.value = value
+  }
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return 1
+  }
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return []
+  }
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return false
+  }
+  /**
+   * @return {ContentFormat}
+   */
+  copy () {
+    return new ContentFormat(this.key, this.value)
+  }
+  /**
+   * @param {number} offset
+   * @return {ContentFormat}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {ContentFormat} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    return false
+  }
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarString(encoder, this.key)
+    encoding.writeVarString(encoder, JSON.stringify(this.value))
+  }
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 6
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentFormat}
+ */
+export const readContentFormat = decoder => new ContentFormat(decoding.readVarString(decoder), JSON.parse(decoding.readVarString(decoder)))

src/structs/ContentJSON.js

@@ -0,0 +1,113 @@
+import {
+  Transaction, Item, StructStore // eslint-disable-line
+} from '../internals.js'
+
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+
+/**
+ * @private
+ */
+export class ContentJSON {
+  /**
+   * @param {Array<any>} arr
+   */
+  constructor (arr) {
+    /**
+     * @type {Array<any>}
+     */
+    this.arr = arr
+  }
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return this.arr.length
+  }
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return this.arr
+  }
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+  /**
+   * @return {ContentJSON}
+   */
+  copy () {
+    return new ContentJSON(this.arr)
+  }
+  /**
+   * @param {number} offset
+   * @return {ContentJSON}
+   */
+  splice (offset) {
+    const right = new ContentJSON(this.arr.slice(offset))
+    this.arr = this.arr.slice(0, offset)
+    return right
+  }
+  /**
+   * @param {ContentJSON} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    this.arr = this.arr.concat(right.arr)
+    return true
+  }
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    const len = this.arr.length
+    encoding.writeVarUint(encoder, len - offset)
+    for (let i = offset; i < len; i++) {
+      const c = this.arr[i]
+      encoding.writeVarString(encoder, c === undefined ? 'undefined' : JSON.stringify(c))
+    }
+  }
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 2
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentJSON}
+ */
+export const readContentJSON = decoder => {
+  const len = decoding.readVarUint(decoder)
+  const cs = []
+  for (let i = 0; i < len; i++) {
+    const c = decoding.readVarString(decoder)
+    if (c === 'undefined') {
+      cs.push(undefined)
+    } else {
+      cs.push(JSON.parse(c))
+    }
+  }
+  return new ContentJSON(cs)
+}

src/structs/ContentString.js

@@ -0,0 +1,96 @@
+import {
+  Transaction, Item, StructStore // eslint-disable-line
+} from '../internals.js'
+
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+
+/**
+ * @private
+ */
+export class ContentString {
+  /**
+   * @param {string} str
+   */
+  constructor (str) {
+    /**
+     * @type {string}
+     */
+    this.str = str
+  }
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return this.str.length
+  }
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return this.str.split('')
+  }
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+  /**
+   * @return {ContentString}
+   */
+  copy () {
+    return new ContentString(this.str)
+  }
+  /**
+   * @param {number} offset
+   * @return {ContentString}
+   */
+  splice (offset) {
+    const right = new ContentString(this.str.slice(offset))
+    this.str = this.str.slice(0, offset)
+    return right
+  }
+  /**
+   * @param {ContentString} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    this.str += right.str
+    return true
+  }
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {}
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {}
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {}
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    encoding.writeVarString(encoder, offset === 0 ? this.str : this.str.slice(offset))
+  }
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 4
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentString}
+ */
+export const readContentString = decoder => new ContentString(decoding.readVarString(decoder))

src/structs/ContentType.js

@@ -0,0 +1,161 @@
+
+import {
+  readYArray,
+  readYMap,
+  readYText,
+  readYXmlElement,
+  readYXmlFragment,
+  readYXmlHook,
+  readYXmlText,
+  StructStore, Transaction, Item, YEvent, AbstractType // eslint-disable-line
+} from '../internals.js'
+
+import * as encoding from 'lib0/encoding.js' // eslint-disable-line
+import * as decoding from 'lib0/decoding.js'
+import * as error from 'lib0/error.js'
+
+/**
+ * @type {Array<function(decoding.Decoder):AbstractType<any>>}
+ * @private
+ */
+export const typeRefs = [
+  readYArray,
+  readYMap,
+  readYText,
+  readYXmlElement,
+  readYXmlFragment,
+  readYXmlHook,
+  readYXmlText
+]
+
+export const YArrayRefID = 0
+export const YMapRefID = 1
+export const YTextRefID = 2
+export const YXmlElementRefID = 3
+export const YXmlFragmentRefID = 4
+export const YXmlHookRefID = 5
+export const YXmlTextRefID = 6
+
+/**
+ * @private
+ */
+export class ContentType {
+  /**
+   * @param {AbstractType<YEvent>} type
+   */
+  constructor (type) {
+    this.type = type
+  }
+  /**
+   * @return {number}
+   */
+  getLength () {
+    return 1
+  }
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    return [this.type]
+  }
+  /**
+   * @return {boolean}
+   */
+  isCountable () {
+    return true
+  }
+  /**
+   * @return {ContentType}
+   */
+  copy () {
+    return new ContentType(this.type._copy())
+  }
+  /**
+   * @param {number} offset
+   * @return {ContentType}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {ContentType} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    return false
+  }
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {
+    this.type._integrate(transaction.doc, item)
+  }
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {
+    let item = this.type._start
+    while (item !== null) {
+      if (!item.deleted) {
+        item.delete(transaction)
+      } else {
+        // Whis will be gc'd later and we want to merge it if possible
+        // 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)
+      }
+      item = item.right
+    }
+    this.type._map.forEach(item => {
+      if (!item.deleted) {
+        item.delete(transaction)
+      } else {
+        // same as above
+        transaction._mergeStructs.add(item.id)
+      }
+    })
+    transaction.changed.delete(this.type)
+    transaction.changedParentTypes.delete(this.type)
+  }
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {
+    let item = this.type._start
+    while (item !== null) {
+      item.gc(store, true)
+      item = item.right
+    }
+    this.type._start = null
+    this.type._map.forEach(/** @param {Item | null} item */ (item) => {
+      while (item !== null) {
+        item.gc(store, true)
+        item = item.left
+      }
+    })
+    this.type._map = new Map()
+  }
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    this.type._write(encoder)
+  }
+  /**
+   * @return {number}
+   */
+  getRef () {
+    return 7
+  }
+}
+
+/**
+ * @private
+ *
+ * @param {decoding.Decoder} decoder
+ * @return {ContentType}
+ */
+export const readContentType = decoder => new ContentType(typeRefs[decoding.readVarUint(decoder)](decoder))

src/structs/GC.js

@@ -21,26 +21,18 @@ export class GC extends AbstractStruct {
    * @param {number} length
    */
   constructor (id, length) {
-    super(id)
+    super(id, length)
-    /**
-     * @type {number}
-     */
-    this._len = length
     this.deleted = true
   }
 
-  get length () {
-    return this._len
-  }
-
   delete () {}
 
   /**
-   * @param {AbstractStruct} right
+   * @param {GC} right
    * @return {boolean}
    */
   mergeWith (right) {
-    this._len += right.length
+    this.length += right.length
     return true
   }
 
@@ -57,7 +49,7 @@ export class GC extends AbstractStruct {
    */
   write (encoder, offset) {
     encoding.writeUint8(encoder, structGCRefNumber)
-    encoding.writeVarUint(encoder, this._len - offset)
+    encoding.writeVarUint(encoder, this.length - offset)
   }
 }
 
@@ -75,15 +67,7 @@ export class GCRef extends AbstractStructRef {
     /**
      * @type {number}
      */
-    this._len = decoding.readVarUint(decoder)
+    this.length = decoding.readVarUint(decoder)
-  }
-  get length () {
-    return this._len
-  }
-  missing () {
-    return [
-      createID(this.id.client, this.id.clock - 1)
-    ]
   }
   /**
    * @param {Transaction} transaction
@@ -95,11 +79,11 @@ export class GCRef extends AbstractStructRef {
     if (offset > 0) {
       // @ts-ignore
       this.id = createID(this.id.client, this.id.clock + offset)
-      this._len = this._len - offset
+      this.length -= offset
     }
     return new GC(
       this.id,
-      this._len
+      this.length
     )
   }
 }

src/structs/Item.js

@@ -10,14 +10,19 @@ import {
   replaceStruct,
   addStruct,
   addToDeleteSet,
-  ItemDeleted,
   findRootTypeKey,
   compareIDs,
   getItem,
-  getItemType,
   getItemCleanEnd,
   getItemCleanStart,
-  YEvent, StructStore, ID, AbstractType, Transaction // eslint-disable-line
+  readContentDeleted,
+  readContentBinary,
+  readContentJSON,
+  readContentString,
+  readContentEmbed,
+  readContentFormat,
+  readContentType,
+  ContentType, ContentDeleted, StructStore, ID, AbstractType, Transaction // eslint-disable-line
 } from '../internals.js'
 
 import * as error from 'lib0/error.js'
@@ -27,28 +32,12 @@ import * as maplib from 'lib0/map.js'
 import * as set from 'lib0/set.js'
 import * as binary from 'lib0/binary.js'
 
-/**
- * @param {AbstractItem} left
- * @param {AbstractItem} right
- * @return {boolean} If true, right is removed from the linked list and should be discarded
- */
-export const mergeItemWith = (left, right) => {
-  if (compareIDs(right.origin, left.lastId) && left.right === right && compareIDs(left.rightOrigin, right.rightOrigin)) {
-    left.right = right.right
-    if (left.right !== null) {
-      left.right.left = left
-    }
-    return true
-  }
-  return false
-}
-
 /**
  * Split leftItem into two items
  * @param {Transaction} transaction
- * @param {AbstractItem} leftItem
+ * @param {Item} leftItem
  * @param {number} diff
- * @return {AbstractItem}
+ * @return {Item}
  *
  * @function
  * @private
@@ -56,14 +45,15 @@ export const mergeItemWith = (left, right) => {
 export const splitItem = (transaction, leftItem, diff) => {
   const id = leftItem.id
   // create rightItem
-  const rightItem = leftItem.copy(
+  const rightItem = new Item(
     createID(id.client, id.clock + diff),
     leftItem,
     createID(id.client, id.clock + diff - 1),
     leftItem.right,
     leftItem.rightOrigin,
     leftItem.parent,
-    leftItem.parentSub
+    leftItem.parentSub,
+    leftItem.content.splice(diff)
   )
   if (leftItem.deleted) {
     rightItem.deleted = true
@@ -80,24 +70,26 @@ export const splitItem = (transaction, leftItem, diff) => {
   if (rightItem.parentSub !== null && rightItem.right === null) {
     rightItem.parent._map.set(rightItem.parentSub, rightItem)
   }
+  leftItem.length = diff
   return rightItem
 }
 
 /**
  * Abstract class that represents any content.
  */
-export class AbstractItem extends AbstractStruct {
+export class Item extends AbstractStruct {
   /**
    * @param {ID} id
-   * @param {AbstractItem | null} left
+   * @param {Item | null} left
    * @param {ID | null} origin
-   * @param {AbstractItem | null} right
+   * @param {Item | null} right
    * @param {ID | null} rightOrigin
    * @param {AbstractType<any>} parent
    * @param {string | null} parentSub
+   * @param {AbstractContent} content
    */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub) {
+  constructor (id, left, origin, right, rightOrigin, parent, parentSub, content) {
-    super(id)
+    super(id, content.getLength())
     /**
      * The item that was originally to the left of this item.
      * @type {ID | null}
@@ -106,12 +98,12 @@ export class AbstractItem extends AbstractStruct {
     this.origin = origin
     /**
      * The item that is currently to the left of this item.
-     * @type {AbstractItem | null}
+     * @type {Item | null}
      */
     this.left = left
     /**
      * The item that is currently to the right of this item.
-     * @type {AbstractItem | null}
+     * @type {Item | null}
      */
     this.right = right
     /**
@@ -143,9 +135,12 @@ export class AbstractItem extends AbstractStruct {
     /**
      * If this type's effect is reundone this type refers to the type that undid
      * this operation.
-     * @type {AbstractItem | null}
+     * @type {Item | null}
      */
     this.redone = null
+    this.content = content
+    this.length = content.getLength()
+    this.countable = content.isCountable()
   }
 
   /**
@@ -159,7 +154,7 @@ export class AbstractItem extends AbstractStruct {
     const parentSub = this.parentSub
     const length = this.length
     /**
-     * @type {AbstractItem|null}
+     * @type {Item|null}
      */
     let o
     // set o to the first conflicting item
@@ -175,11 +170,11 @@ export class AbstractItem extends AbstractStruct {
     }
     // TODO: use something like DeleteSet here (a tree implementation would be best)
     /**
-     * @type {Set<AbstractItem>}
+     * @type {Set<Item>}
      */
     const conflictingItems = new Set()
     /**
-     * @type {Set<AbstractItem>}
+     * @type {Set<Item>}
      */
     const itemsBeforeOrigin = new Set()
     // Let c in conflictingItems, b in itemsBeforeOrigin
@@ -238,8 +233,8 @@ export class AbstractItem extends AbstractStruct {
       parent._length += length
     }
     addStruct(store, this)
+    this.content.integrate(transaction, this)
     maplib.setIfUndefined(transaction.changed, parent, set.create).add(parentSub)
-    // @ts-ignore
     if ((parent._item !== null && parent._item.deleted) || (this.right !== null && parentSub !== null)) {
       // delete if parent is deleted or if this is not the current attribute value of parent
       this.delete(transaction)
@@ -270,29 +265,11 @@ export class AbstractItem extends AbstractStruct {
     return n
   }
 
-  /**
-   * Creates an Item with the same effect as this Item (without position effect)
-   *
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @return {AbstractItem}
-   *
-   * @private
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    throw error.methodUnimplemented()
-  }
-
   /**
    * Redoes the effect of this operation.
    *
    * @param {Transaction} transaction The Yjs instance.
-   * @param {Set<AbstractItem>} redoitems
+   * @param {Set<Item>} redoitems
    *
    * @private
    */
@@ -343,7 +320,7 @@ export class AbstractItem extends AbstractStruct {
         right = right.right
       }
     }
-    this.redone = this.copy(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, this.parentSub)
+    this.redone = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, this.parentSub, this.content.copy())
     this.redone.integrate(transaction)
     return true
   }
@@ -354,46 +331,31 @@ export class AbstractItem extends AbstractStruct {
   get lastId () {
     return createID(this.id.client, this.id.clock + this.length - 1)
   }
-
   /**
-   * Computes the length of this Item.
+   * Try to merge two items
-   */
-  get length () {
-    return 1
-  }
-
-  /**
-   * Should return false if this Item is some kind of meta information
-   * (e.g. format information).
    *
-   * * Whether this Item should be addressable via `yarray.get(i)`
+   * @param {Item} right
-   * * Whether this Item should be counted when computing yarray.length
+   * @return {boolean}
    */
-  get countable () {
+  mergeWith (right) {
+    if (
+      compareIDs(right.origin, this.lastId) &&
+      this.right === right &&
+      compareIDs(this.rightOrigin, right.rightOrigin) &&
+      this.id.client === right.id.client &&
+      this.id.clock + this.length === right.id.clock &&
+      this.deleted === right.deleted &&
+      this.content.constructor === right.content.constructor &&
+      this.content.mergeWith(right.content)
+    ) {
+      this.right = right.right
+      if (this.right !== null) {
+        this.right.left = this
+      }
+      this.length += right.length
       return true
     }
-
+    return false
-  /**
-   * Do not call directly. Always split via StructStore!
-   *
-   * Splits this Item so that another Item can be inserted in-between.
-   * This must be overwritten if _length > 1
-   * Returns right part after split
-   *
-   * (see {@link ItemJSON}/{@link ItemString} for implementation)
-   *
-   * Does not integrate the struct, nor store it in struct store.
-   *
-   * This method should only be cally by StructStore.
-   *
-   * @param {Transaction} transaction
-   * @param {number} diff
-   * @return {AbstractItem}
-   *
-   * @private
-   */
-  splitAt (transaction, diff) {
-    throw error.methodUnimplemented()
   }
 
   /**
@@ -411,16 +373,10 @@ export class AbstractItem extends AbstractStruct {
       this.deleted = true
       addToDeleteSet(transaction.deleteSet, this.id, this.length)
       maplib.setIfUndefined(transaction.changed, parent, set.create).add(this.parentSub)
+      this.content.delete(transaction)
     }
   }
 
-  /**
-   * @param {StructStore} store
-   *
-   * @private
-   */
-  gcChildren (store) { }
-
   /**
    * @param {StructStore} store
    * @param {boolean} parentGCd
@@ -431,30 +387,12 @@ export class AbstractItem extends AbstractStruct {
     if (!this.deleted) {
       throw error.unexpectedCase()
     }
-    let r
+    this.content.gc(store)
     if (parentGCd) {
-      r = new GC(this.id, this.length)
+      replaceStruct(store, this, new GC(this.id, this.length))
     } else {
-      r = new ItemDeleted(this.id, this.left, this.origin, this.right, this.rightOrigin, this.parent, this.parentSub, this.length)
+      this.content = new ContentDeleted(this.length)
-      if (r.right !== null) {
-        r.right.left = r
-      } else if (r.parentSub !== null) {
-        r.parent._map.set(r.parentSub, r)
     }
-      if (r.left !== null) {
-        r.left.right = r
-      } else if (r.parentSub === null) {
-        r.parent._start = r
-      }
-    }
-    replaceStruct(store, this, r)
-  }
-
-  /**
-   * @return {Array<any>}
-   */
-  getContent () {
-    throw error.methodUnimplemented()
   }
 
   /**
@@ -465,15 +403,14 @@ export class AbstractItem extends AbstractStruct {
    *
    * @param {encoding.Encoder} encoder The encoder to write data to.
    * @param {number} offset
-   * @param {number} encodingRef
    *
    * @private
    */
-  write (encoder, offset, encodingRef) {
+  write (encoder, offset) {
     const origin = offset > 0 ? createID(this.id.client, this.id.clock + offset - 1) : this.origin
     const rightOrigin = this.rightOrigin
     const parentSub = this.parentSub
-    const info = (encodingRef & binary.BITS5) |
+    const info = (this.content.getRef() & binary.BITS5) |
       (origin === null ? 0 : binary.BIT8) | // origin is defined
       (rightOrigin === null ? 0 : binary.BIT7) | // right origin is defined
       (parentSub === null ? 0 : binary.BIT6) // parentSub is non-null
@@ -489,26 +426,129 @@ export class AbstractItem extends AbstractStruct {
       if (parent._item === null) {
         // parent type on y._map
         // find the correct key
-        // @ts-ignore we know that y exists
         const ykey = findRootTypeKey(parent)
         encoding.writeVarUint(encoder, 1) // write parentYKey
         encoding.writeVarString(encoder, ykey)
       } else {
         encoding.writeVarUint(encoder, 0) // write parent id
-        // @ts-ignore _item is defined because parent is integrated
         writeID(encoder, parent._item.id)
       }
       if (parentSub !== null) {
         encoding.writeVarString(encoder, parentSub)
       }
     }
+    this.content.write(encoder, offset)
+  }
+}
+
+/**
+ * @param {decoding.Decoder} decoder
+ * @param {number} info
+ */
+const readItemContent = (decoder, info) => contentRefs[info & binary.BITS5](decoder)
+
+/**
+ * A lookup map for reading Item content.
+ *
+ * @type {Array<function(decoding.Decoder):AbstractContent>}
+ */
+export const contentRefs = [
+  () => { throw error.unexpectedCase() }, // GC is not ItemContent
+  readContentDeleted,
+  readContentJSON,
+  readContentBinary,
+  readContentString,
+  readContentEmbed,
+  readContentFormat,
+  readContentType
+]
+
+/**
+ * Do not implement this class!
+ */
+export class AbstractContent {
+  /**
+   * @return {number}
+   */
+  getLength () {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @return {Array<any>}
+   */
+  getContent () {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * Should return false if this Item is some kind of meta information
+   * (e.g. format information).
+   *
+   * * Whether this Item should be addressable via `yarray.get(i)`
+   * * Whether this Item should be counted when computing yarray.length
+   *
+   * @return {boolean}
+   */
+  isCountable () {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @return {AbstractContent}
+   */
+  copy () {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {number} offset
+   * @return {AbstractContent}
+   */
+  splice (offset) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {AbstractContent} right
+   * @return {boolean}
+   */
+  mergeWith (right) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {Transaction} transaction
+   * @param {Item} item
+   */
+  integrate (transaction, item) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {Transaction} transaction
+   */
+  delete (transaction) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {StructStore} store
+   */
+  gc (store) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @param {encoding.Encoder} encoder
+   * @param {number} offset
+   */
+  write (encoder, offset) {
+    throw error.methodUnimplemented()
+  }
+  /**
+   * @return {number}
+   */
+  getRef () {
+    throw error.methodUnimplemented()
   }
 }
 
 /**
  * @private
  */
-export class AbstractItemRef extends AbstractStructRef {
+export class ItemRef extends AbstractStructRef {
   /**
    * @param {decoding.Decoder} decoder
    * @param {ID} id
@@ -558,73 +598,44 @@ export class AbstractItemRef extends AbstractStructRef {
     if (this.parent !== null) {
       missing.push(this.parent)
     }
-  }
-}
-
-/**
- * @param {AbstractItemRef} item
- * @param {number} offset
- *
- * @function
- * @private
- */
-export const changeItemRefOffset = (item, offset) => {
-  item.id = createID(item.id.client, item.id.clock + offset)
-  item.left = createID(item.id.client, item.id.clock - 1)
-}
-
-export class ItemParams {
     /**
-   * @param {AbstractItem?} left
+     * @type {AbstractContent}
-   * @param {AbstractItem?} right
-   * @param {AbstractType<YEvent>?} parent
-   * @param {string|null} parentSub
      */
-  constructor (left, right, parent, parentSub) {
+    this.content = readItemContent(decoder, info)
-    this.left = left
+    this.length = this.content.getLength()
-    this.right = right
-    this.parent = parent
-    this.parentSub = parentSub
   }
-}
+  /**
-
-/**
- * Outsourcing some of the logic of computing the item params from a received struct.
- * If parent === null, it is expected to gc the read struct. Otherwise apply it.
- *
    * @param {Transaction} transaction
    * @param {StructStore} store
- * @param {ID|null} leftid
+   * @param {number} offset
- * @param {ID|null} rightid
+   * @return {Item|GC}
- * @param {ID|null} parentid
- * @param {string|null} parentSub
- * @param {string|null} parentYKey
- * @return {ItemParams}
- *
- * @private
- * @function
    */
-export const computeItemParams = (transaction, store, leftid, rightid, parentid, parentSub, parentYKey) => {
+  toStruct (transaction, store, offset) {
-  const left = leftid === null ? null : getItemCleanEnd(transaction, store, leftid)
+    if (offset > 0) {
-  const right = rightid === null ? null : getItemCleanStart(transaction, store, rightid)
+      /**
+       * @type {ID}
+       */
+      const id = this.id
+      this.id = createID(id.client, id.clock + offset)
+      this.left = createID(this.id.client, this.id.clock - 1)
+      this.content = this.content.splice(offset)
+    }
+
+    const left = this.left === null ? null : getItemCleanEnd(transaction, store, this.left)
+    const right = this.right === null ? null : getItemCleanStart(transaction, store, this.right)
     let parent = null
-  if (parentid !== null) {
+    let parentSub = this.parentSub
-    const parentItem = getItemType(store, parentid)
+    if (this.parent !== null) {
-    switch (parentItem.constructor) {
+      const parentItem = getItem(store, this.parent)
-      case ItemDeleted:
-      case GC:
-        break
-      default:
       // 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 probably don't have
+      // deleted. This is why we check if left is GC'd. Strictly we don't have
       // to check if right is GC'd, but we will in case we run into future issues
       if (!parentItem.deleted && (left === null || left.constructor !== GC) && (right === null || right.constructor !== GC)) {
-          parent = parentItem.type
+        parent = /** @type {ContentType} */ (parentItem.content).type
       }
-    }
+    } else if (this.parentYKey !== null) {
-  } else if (parentYKey !== null) {
+      parent = transaction.doc.get(this.parentYKey)
-    parent = transaction.doc.get(parentYKey)
     } else if (left !== null) {
       if (left.constructor !== GC) {
         parent = left.parent
@@ -638,5 +649,18 @@ export const computeItemParams = (transaction, store, leftid, rightid, parentid,
     } else {
       throw error.unexpectedCase()
     }
-  return new ItemParams(left, right, parent, parentSub)
+
+    return parent === null
+      ? new GC(this.id, this.length)
+      : new Item(
+        this.id,
+        left,
+        this.left,
+        right,
+        this.right,
+        parent,
+        parentSub,
+        this.content
+      )
+  }
 }

src/structs/ItemBinary.js

@@ -1,99 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  GC,
-  StructStore, Transaction, AbstractType, ID // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-import * as buffer from 'lib0/buffer.js'
-
-/**
- * @private
- */
-export const structBinaryRefNumber = 1
-
-/**
- * @private
- */
-export class ItemBinary extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {Uint8Array} content
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, content) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this.content = content
-  }
-  getContent () {
-    return [this.content]
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemBinary(id, left, origin, right, rightOrigin, parent, parentSub, this.content)
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structBinaryRefNumber)
-    encoding.writeVarUint8Array(encoder, this.content)
-  }
-}
-
-/**
- * @private
- */
-export class ItemBinaryRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {Uint8Array}
-     */
-    this.content = buffer.copyUint8Array(decoding.readVarUint8Array(decoder))
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemBinary|GC}
-   */
-  toStruct (transaction, store, offset) {
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemBinary(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.content
-      )
-  }
-}

src/structs/ItemDeleted.js

@@ -1,155 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  changeItemRefOffset,
-  GC,
-  splitItem,
-  addToDeleteSet,
-  mergeItemWith,
-  StructStore, Transaction, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structDeletedRefNumber = 2
-
-/**
- * @private
- */
-export class ItemDeleted extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {number} length
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, length) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this._len = length
-    this.deleted = true
-  }
-  get length () {
-    return this._len
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemDeleted(id, left, origin, right, rightOrigin, parent, parentSub, this.length)
-  }
-  /**
-   * @param {Transaction} transaction
-   */
-  integrate (transaction) {
-    super.integrate(transaction)
-    addToDeleteSet(transaction.deleteSet, this.id, this.length)
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {number} diff
-   */
-  splitAt (transaction, diff) {
-    /**
-     * @type {ItemDeleted}
-     */
-    // @ts-ignore
-    const right = splitItem(transaction, this, diff)
-    right._len -= diff
-    this._len = diff
-    return right
-  }
-  /**
-   * @param {ItemDeleted} right
-   * @return {boolean}
-   */
-  mergeWith (right) {
-    if (mergeItemWith(this, right)) {
-      this._len += right._len
-      return true
-    }
-    return false
-  }
-
-  /**
-   * @param {StructStore} store
-   * @param {boolean} parentGCd
-   *
-   * @private
-   */
-  gc (store, parentGCd) {
-    if (parentGCd) {
-      super.gc(store, parentGCd)
-    }
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structDeletedRefNumber)
-    encoding.writeVarUint(encoder, this.length - offset)
-  }
-}
-
-/**
- * @private
- */
-export class ItemDeletedRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {number}
-     */
-    this.len = decoding.readVarUint(decoder)
-  }
-  get length () {
-    return this.len
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemDeleted|GC}
-   */
-  toStruct (transaction, store, offset) {
-    if (offset > 0) {
-      changeItemRefOffset(this, offset)
-      this.len = this.len - offset
-    }
-
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemDeleted(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.len
-      )
-  }
-}

src/structs/ItemEmbed.js

@@ -1,95 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  GC,
-  Transaction, StructStore, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structEmbedRefNumber = 3
-
-/**
- * @private
- */
-export class ItemEmbed extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {Object} embed
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, embed) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this.embed = embed
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemEmbed(id, left, origin, right, rightOrigin, parent, parentSub, this.embed)
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structEmbedRefNumber)
-    encoding.writeVarString(encoder, JSON.stringify(this.embed))
-  }
-}
-
-/**
- * @private
- */
-export class ItemEmbedRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {Object}
-     */
-    this.embed = JSON.parse(decoding.readVarString(decoder))
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemEmbed|GC}
-   */
-  toStruct (transaction, store, offset) {
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemEmbed(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.embed
-      )
-  }
-}

src/structs/ItemFormat.js

@@ -1,103 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  GC,
-  Transaction, StructStore, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structFormatRefNumber = 4
-
-/**
- * @private
- */
-export class ItemFormat extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {string} key
-   * @param {any} value
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, key, value) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this.key = key
-    this.value = value
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemFormat(id, left, origin, right, rightOrigin, parent, parentSub, this.key, this.value)
-  }
-  get countable () {
-    return false
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structFormatRefNumber)
-    encoding.writeVarString(encoder, this.key)
-    encoding.writeVarString(encoder, JSON.stringify(this.value))
-  }
-}
-
-/**
- * @private
- */
-export class ItemFormatRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {string}
-     */
-    this.key = decoding.readVarString(decoder)
-    this.value = JSON.parse(decoding.readVarString(decoder))
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemFormat|GC}
-   */
-  toStruct (transaction, store, offset) {
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemFormat(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.key,
-        this.value
-      )
-  }
-}

src/structs/ItemJSON.js

@@ -1,153 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  splitItem,
-  changeItemRefOffset,
-  GC,
-  mergeItemWith,
-  Transaction, StructStore, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structJSONRefNumber = 5
-
-/**
- * @private
- */
-export class ItemJSON extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {Array<any>} content
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, content) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    /**
-     * @type {Array<any>}
-     */
-    this.content = content
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemJSON(id, left, origin, right, rightOrigin, parent, parentSub, this.content)
-  }
-  get length () {
-    return this.content.length
-  }
-  getContent () {
-    return this.content
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {number} diff
-   */
-  splitAt (transaction, diff) {
-    /**
-     * @type {ItemJSON}
-     */
-    // @ts-ignore
-    const right = splitItem(transaction, this, diff)
-    right.content = this.content.splice(diff)
-    return right
-  }
-  /**
-   * @param {ItemJSON} right
-   * @return {boolean}
-   */
-  mergeWith (right) {
-    if (mergeItemWith(this, right)) {
-      this.content = this.content.concat(right.content)
-      return true
-    }
-    return false
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structJSONRefNumber)
-    const len = this.content.length
-    encoding.writeVarUint(encoder, len - offset)
-    for (let i = offset; i < len; i++) {
-      const c = this.content[i]
-      encoding.writeVarString(encoder, c === undefined ? 'undefined' : JSON.stringify(c))
-    }
-  }
-}
-
-/**
- * @private
- */
-export class ItemJSONRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    const len = decoding.readVarUint(decoder)
-    const cs = []
-    for (let i = 0; i < len; i++) {
-      const c = decoding.readVarString(decoder)
-      if (c === 'undefined') {
-        cs.push(undefined)
-      } else {
-        cs.push(JSON.parse(c))
-      }
-    }
-    /**
-     * @type {Array<any>}
-     */
-    this.content = cs
-  }
-  get length () {
-    return this.content.length
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemJSON|GC}
-   */
-  toStruct (transaction, store, offset) {
-    if (offset > 0) {
-      changeItemRefOffset(this, offset)
-      this.content = this.content.slice(offset)
-    }
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemJSON(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.content
-      )
-  }
-}

src/structs/ItemString.js

@@ -1,138 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  splitItem,
-  changeItemRefOffset,
-  GC,
-  mergeItemWith,
-  Transaction, StructStore, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js'
-import * as decoding from 'lib0/decoding.js'
-
-export const structStringRefNumber = 6
-
-/**
- * @private
- */
-export class ItemString extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {string} string
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, string) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    /**
-     * @type {string}
-     */
-    this.string = string
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemString(id, left, origin, right, rightOrigin, parent, parentSub, this.string)
-  }
-  getContent () {
-    return this.string.split('')
-  }
-  get length () {
-    return this.string.length
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {number} diff
-   * @return {ItemString}
-   */
-  splitAt (transaction, diff) {
-    /**
-     * @type {ItemString}
-     */
-    // @ts-ignore
-    const right = splitItem(transaction, this, diff)
-    right.string = this.string.slice(diff)
-    this.string = this.string.slice(0, diff)
-    return right
-  }
-  /**
-   * @param {ItemString} right
-   * @return {boolean}
-   */
-  mergeWith (right) {
-    if (mergeItemWith(this, right)) {
-      this.string += right.string
-      return true
-    }
-    return false
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structStringRefNumber)
-    encoding.writeVarString(encoder, offset === 0 ? this.string : this.string.slice(offset))
-  }
-}
-
-/**
- * @private
- */
-export class ItemStringRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    /**
-     * @type {string}
-     */
-    this.string = decoding.readVarString(decoder)
-  }
-  get length () {
-    return this.string.length
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemString|GC}
-   */
-  toStruct (transaction, store, offset) {
-    if (offset > 0) {
-      changeItemRefOffset(this, offset)
-      this.string = this.string.slice(offset)
-    }
-
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemString(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.string
-      )
-  }
-}

src/structs/ItemType.js

@@ -1,199 +0,0 @@
-
-import {
-  AbstractItem,
-  AbstractItemRef,
-  computeItemParams,
-  readYArray,
-  readYMap,
-  readYText,
-  readYXmlElement,
-  readYXmlFragment,
-  readYXmlHook,
-  readYXmlText,
-  StructStore, GC, Transaction, ID, AbstractType // eslint-disable-line
-} from '../internals.js'
-
-import * as encoding from 'lib0/encoding.js' // eslint-disable-line
-import * as decoding from 'lib0/decoding.js'
-
-/**
- * @private
- */
-export const structTypeRefNumber = 7
-
-/**
- * @type {Array<function(decoding.Decoder):AbstractType<any>>}
- * @private
- */
-export const typeRefs = [
-  readYArray,
-  readYMap,
-  readYText,
-  readYXmlElement,
-  readYXmlFragment,
-  readYXmlHook,
-  readYXmlText
-]
-
-export const YArrayRefID = 0
-export const YMapRefID = 1
-export const YTextRefID = 2
-export const YXmlElementRefID = 3
-export const YXmlFragmentRefID = 4
-export const YXmlHookRefID = 5
-export const YXmlTextRefID = 6
-
-/**
- * @private
- */
-export class ItemType extends AbstractItem {
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @param {AbstractType<any>} type
-   */
-  constructor (id, left, origin, right, rightOrigin, parent, parentSub, type) {
-    super(id, left, origin, right, rightOrigin, parent, parentSub)
-    this.type = type
-  }
-
-  getContent () {
-    return [this.type]
-  }
-  /**
-   * @param {ID} id
-   * @param {AbstractItem | null} left
-   * @param {ID | null} origin
-   * @param {AbstractItem | null} right
-   * @param {ID | null} rightOrigin
-   * @param {AbstractType<any>} parent
-   * @param {string | null} parentSub
-   * @return {ItemType}
-   */
-  copy (id, left, origin, right, rightOrigin, parent, parentSub) {
-    return new ItemType(id, left, origin, right, rightOrigin, parent, parentSub, this.type._copy())
-  }
-  /**
-   * @param {Transaction} transaction
-   */
-  integrate (transaction) {
-    super.integrate(transaction)
-    this.type._integrate(transaction.doc, this)
-  }
-  /**
-   * @param {encoding.Encoder} encoder
-   * @param {number} offset
-   */
-  write (encoder, offset) {
-    super.write(encoder, offset, structTypeRefNumber)
-    this.type._write(encoder)
-  }
-  /**
-   * Mark this Item as deleted.
-   *
-   * @param {Transaction} transaction The Yjs instance
-   * @private
-   */
-  delete (transaction) {
-    if (!this.deleted) {
-      super.delete(transaction)
-      let item = this.type._start
-      while (item !== null) {
-        if (!item.deleted) {
-          item.delete(transaction)
-        } else {
-          // Whis will be gc'd later and we want to merge it if possible
-          // 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)
-        }
-        item = item.right
-      }
-      this.type._map.forEach(item => {
-        if (!item.deleted) {
-          item.delete(transaction)
-        } else {
-          // same as above
-          transaction._mergeStructs.add(item.id)
-        }
-      })
-      transaction.changed.delete(this.type)
-      transaction.changedParentTypes.delete(this.type)
-    }
-  }
-
-  /**
-   * @param {StructStore} store
-   */
-  gcChildren (store) {
-    let item = this.type._start
-    while (item !== null) {
-      item.gc(store, true)
-      item = item.right
-    }
-    this.type._start = null
-    this.type._map.forEach(item => {
-      while (item !== null) {
-        item.gc(store, true)
-        // @ts-ignore
-        item = item.left
-      }
-    })
-    this._map = new Map()
-  }
-
-  /**
-   * @param {StructStore} store
-   * @param {boolean} parentGCd
-   */
-  gc (store, parentGCd) {
-    this.gcChildren(store)
-    super.gc(store, parentGCd)
-  }
-}
-
-/**
- * @private
- */
-export class ItemTypeRef extends AbstractItemRef {
-  /**
-   * @param {decoding.Decoder} decoder
-   * @param {ID} id
-   * @param {number} info
-   */
-  constructor (decoder, id, info) {
-    super(decoder, id, info)
-    const typeRef = decoding.readVarUint(decoder)
-    /**
-     * @type {AbstractType<any>}
-     */
-    this.type = typeRefs[typeRef](decoder)
-  }
-  /**
-   * @param {Transaction} transaction
-   * @param {StructStore} store
-   * @param {number} offset
-   * @return {ItemType|GC}
-   */
-  toStruct (transaction, store, offset) {
-    const { left, right, parent, parentSub } = computeItemParams(transaction, store, this.left, this.right, this.parent, this.parentSub, this.parentYKey)
-    return parent === null
-      ? new GC(this.id, this.length)
-      : new ItemType(
-        this.id,
-        left,
-        this.left,
-        right,
-        this.right,
-        parent,
-        parentSub,
-        this.type
-      )
-  }
-}

src/types/AbstractType.js

@@ -4,14 +4,14 @@ import {
   callEventHandlerListeners,
   addEventHandlerListener,
   createEventHandler,
-  ItemType,
   nextID,
   isVisible,
-  ItemJSON,
+  ContentType,
-  ItemBinary,
+  ContentJSON,
+  ContentBinary,
   createID,
   getItemCleanStart,
-  Doc, Snapshot, Transaction, EventHandler, YEvent, AbstractItem, // eslint-disable-line
+  Doc, Snapshot, Transaction, EventHandler, YEvent, Item, // eslint-disable-line
 } from '../internals.js'
 
 import * as map from 'lib0/map.js'
@@ -49,17 +49,17 @@ export const callTypeObservers = (type, transaction, event) => {
 export class AbstractType {
   constructor () {
     /**
-     * @type {ItemType|null}
+     * @type {Item|null}
      */
     this._item = null
     /**
      * @private
-     * @type {Map<string,AbstractItem>}
+     * @type {Map<string,Item>}
      */
     this._map = new Map()
     /**
      * @private
-     * @type {AbstractItem|null}
+     * @type {Item|null}
      */
     this._start = null
     /**
@@ -88,7 +88,7 @@ export class AbstractType {
    * * Observer functions are fired
    *
    * @param {Doc} y The Yjs instance
-   * @param {ItemType|null} item
+   * @param {Item|null} item
    * @private
    */
   _integrate (y, item) {
@@ -187,7 +187,7 @@ export const typeListToArray = type => {
   let n = type._start
   while (n !== null) {
     if (n.countable && !n.deleted) {
-      const c = n.getContent()
+      const c = n.content.getContent()
       for (let i = 0; i < c.length; i++) {
         cs.push(c[i])
       }
@@ -210,7 +210,7 @@ export const typeListToArraySnapshot = (type, snapshot) => {
   let n = type._start
   while (n !== null) {
     if (n.countable && isVisible(n, snapshot)) {
-      const c = n.getContent()
+      const c = n.content.getContent()
       for (let i = 0; i < c.length; i++) {
         cs.push(c[i])
       }
@@ -234,7 +234,7 @@ export const typeListForEach = (type, f) => {
   let n = type._start
   while (n !== null) {
     if (n.countable && !n.deleted) {
-      const c = n.getContent()
+      const c = n.content.getContent()
       for (let i = 0; i < c.length; i++) {
         f(c[i], index++, type)
       }
@@ -295,7 +295,7 @@ export const typeListCreateIterator = type => {
           }
         }
         // we found n, so we can set currentContent
-        currentContent = n.getContent()
+        currentContent = n.content.getContent()
         currentContentIndex = 0
         n = n.right // we used the content of n, now iterate to next
       }
@@ -328,7 +328,7 @@ export const typeListForEachSnapshot = (type, f, snapshot) => {
   let n = type._start
   while (n !== null) {
     if (n.countable && isVisible(n, snapshot)) {
-      const c = n.getContent()
+      const c = n.content.getContent()
       for (let i = 0; i < c.length; i++) {
         f(c[i], index++, type)
       }
@@ -349,7 +349,7 @@ export const typeListGet = (type, index) => {
   for (let n = type._start; n !== null; n = n.right) {
     if (!n.deleted && n.countable) {
       if (index < n.length) {
-        return n.getContent()[index]
+        return n.content.getContent()[index]
       }
       index -= n.length
     }
@@ -359,7 +359,7 @@ export const typeListGet = (type, index) => {
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem?} referenceItem
+ * @param {Item?} referenceItem
  * @param {Array<Object<string,any>|Array<any>|boolean|number|string|Uint8Array>} content
  *
  * @private
@@ -374,7 +374,7 @@ export const typeListInsertGenericsAfter = (transaction, parent, referenceItem,
   let jsonContent = []
   const packJsonContent = () => {
     if (jsonContent.length > 0) {
-      left = new ItemJSON(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, jsonContent)
+      left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentJSON(jsonContent))
       left.integrate(transaction)
       jsonContent = []
     }
@@ -393,12 +393,12 @@ export const typeListInsertGenericsAfter = (transaction, parent, referenceItem,
         switch (c.constructor) {
           case Uint8Array:
           case ArrayBuffer:
-            left = new ItemBinary(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new Uint8Array(/** @type {Uint8Array} */ (c)))
+            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.integrate(transaction)
             break
           default:
             if (c instanceof AbstractType) {
-              left = new ItemType(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, c)
+              left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentType(c))
               left.integrate(transaction)
             } else {
               throw new Error('Unexpected content type in insert operation')
@@ -501,28 +501,30 @@ export const typeMapDelete = (transaction, parent, key) => {
  */
 export const typeMapSet = (transaction, parent, key, value) => {
   const left = parent._map.get(key) || null
+  let content
   if (value == null) {
-    new ItemJSON(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, [value]).integrate(transaction)
+    content = new ContentJSON([value])
-    return
+  } else {
-  }
     switch (value.constructor) {
       case Number:
       case Object:
       case Boolean:
       case Array:
       case String:
-      new ItemJSON(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, [value]).integrate(transaction)
+        content = new ContentJSON([value])
         break
       case Uint8Array:
-      new ItemBinary(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, value).integrate(transaction)
+        content = new ContentBinary(value)
         break
       default:
         if (value instanceof AbstractType) {
-        new ItemType(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, value).integrate(transaction)
+          content = new ContentType(value)
         } else {
           throw new Error('Unexpected content type')
         }
     }
+  }
+  new Item(nextID(transaction), left, left === null ? null : left.lastId, null, null, parent, key, content).integrate(transaction)
 }
 
 /**
@@ -535,7 +537,7 @@ export const typeMapSet = (transaction, parent, key, value) => {
  */
 export const typeMapGet = (parent, key) => {
   const val = parent._map.get(key)
-  return val !== undefined && !val.deleted ? val.getContent()[0] : undefined
+  return val !== undefined && !val.deleted ? val.content.getContent()[val.length - 1] : undefined
 }
 
 /**
@@ -552,7 +554,7 @@ export const typeMapGetAll = (parent) => {
   let res = {}
   for (const [key, value] of parent._map) {
     if (!value.deleted) {
-      res[key] = value.getContent()[value.length - 1]
+      res[key] = value.content.getContent()[value.length - 1]
     }
   }
   return res
@@ -585,11 +587,11 @@ export const typeMapGetSnapshot = (parent, key, snapshot) => {
   while (v !== null && (!snapshot.sm.has(v.id.client) || v.id.clock >= (snapshot.sm.get(v.id.client) || 0))) {
     v = v.left
   }
-  return v !== null && isVisible(v, snapshot) ? v.getContent()[v.length - 1] : undefined
+  return v !== null && isVisible(v, snapshot) ? v.content.getContent()[v.length - 1] : undefined
 }
 
 /**
- * @param {Map<string,AbstractItem>} map
+ * @param {Map<string,Item>} map
  * @return {IterableIterator<Array<any>>}
  *
  * @private

src/types/YArray.js

@@ -15,7 +15,7 @@ import {
   YArrayRefID,
   callTypeObservers,
   transact,
-  Doc, Transaction, ItemType, // eslint-disable-line
+  Doc, Transaction, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as decoding from 'lib0/decoding.js' // eslint-disable-line
@@ -59,14 +59,13 @@ export class YArray extends AbstractType {
    * * Observer functions are fired
    *
    * @param {Doc} y The Yjs instance
-   * @param {ItemType} item
+   * @param {Item} item
    *
    * @private
    */
   _integrate (y, item) {
     super._integrate(y, item)
-    // @ts-ignore
+    this.insert(0, /** @type {Array} */ (this._prelimContent))
-    this.insert(0, this._prelimContent)
     this._prelimContent = null
   }
   get length () {
@@ -106,8 +105,7 @@ export class YArray extends AbstractType {
         typeListInsertGenerics(transaction, this, index, content)
       })
     } else {
-      // @ts-ignore _prelimContent is defined because this is not yet integrated
+      /** @type {Array} */ (this._prelimContent).splice(index, 0, ...content)
-      this._prelimContent.splice(index, 0, ...content)
     }
   }
 
@@ -132,8 +130,7 @@ export class YArray extends AbstractType {
         typeListDelete(transaction, this, index, length)
       })
     } else {
-      // @ts-ignore _prelimContent is defined because this is not yet integrated
+      /** @type {Array} */ (this._prelimContent).splice(index, length)
-      this._prelimContent.splice(index, length)
     }
   }
 
@@ -175,8 +172,7 @@ export class YArray extends AbstractType {
    *                 callback function
    */
   map (f) {
-    // @ts-ignore
+    return typeListMap(this, /** @type {any} */ (f))
-    return typeListMap(this, f)
   }
 
   /**

src/types/YMap.js

@@ -14,7 +14,7 @@ import {
   YMapRefID,
   callTypeObservers,
   transact,
-  Doc, Transaction, ItemType, // eslint-disable-line
+  Doc, Transaction, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -61,14 +61,13 @@ export class YMap extends AbstractType {
    * * Observer functions are fired
    *
    * @param {Doc} y The Yjs instance
-   * @param {ItemType} item
+   * @param {Item} item
    *
    * @private
    */
   _integrate (y, item) {
     super._integrate(y, item)
-    // @ts-ignore
+    for (let [key, value] of /** @type {Map<string, any>} */ (this._prelimContent)) {
-    for (let [key, value] of this._prelimContent) {
       this.set(key, value)
     }
     this._prelimContent = null
@@ -97,7 +96,7 @@ export class YMap extends AbstractType {
     const map = {}
     for (let [key, item] of this._map) {
       if (!item.deleted) {
-        const v = item.getContent()[0]
+        const v = item.content.getContent()[item.length - 1]
         map[key] = v instanceof AbstractType ? v.toJSON() : v
       }
     }
@@ -119,7 +118,7 @@ export class YMap extends AbstractType {
    * @return {Iterator<string>}
    */
   values () {
-    return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => v[1].getContent()[v[1].length - 1])
+    return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => v[1].content.getContent()[v[1].length - 1])
   }
 
   /**
@@ -128,7 +127,7 @@ export class YMap extends AbstractType {
    * @return {IterableIterator<any>}
    */
   entries () {
-    return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => [v[0], v[1].getContent()[v[1].length - 1]])
+    return iterator.iteratorMap(createMapIterator(this._map), /** @param {any} v */ v => [v[0], v[1].content.getContent()[v[1].length - 1]])
   }
 
   /**
@@ -149,8 +148,7 @@ export class YMap extends AbstractType {
         typeMapDelete(transaction, this, key)
       })
     } else {
-      // @ts-ignore
+      /** @type {Map<string, any>} */ (this._prelimContent).delete(key)
-      this._prelimContent.delete(key)
     }
   }
 
@@ -166,8 +164,7 @@ export class YMap extends AbstractType {
         typeMapSet(transaction, this, key, value)
       })
     } else {
-      // @ts-ignore
+      /** @type {Map<string, any>} */ (this._prelimContent).set(key, value)
-      this._prelimContent.set(key, value)
     }
     return value
   }
@@ -179,8 +176,7 @@ export class YMap extends AbstractType {
    * @return {T|undefined}
    */
   get (key) {
-    // @ts-ignore
+    return /** @type {any} */ (typeMapGet(this, key))
-    return typeMapGet(this, key)
   }
 
   /**

src/types/YText.js

@@ -5,9 +5,6 @@
 
 import {
   YEvent,
-  ItemEmbed,
-  ItemString,
-  ItemFormat,
   AbstractType,
   nextID,
   createID,
@@ -16,7 +13,10 @@ import {
   YTextRefID,
   callTypeObservers,
   transact,
-  Doc, ItemType, AbstractItem, Snapshot, StructStore, Transaction // eslint-disable-line
+  ContentEmbed,
+  ContentFormat,
+  ContentString,
+  Doc, Item, Snapshot, StructStore, Transaction // eslint-disable-line
 } from '../internals.js'
 
 import * as decoding from 'lib0/decoding.js' // eslint-disable-line
@@ -24,8 +24,8 @@ import * as encoding from 'lib0/encoding.js'
 
 export class ItemListPosition {
   /**
-   * @param {AbstractItem|null} left
+   * @param {Item|null} left
-   * @param {AbstractItem|null} right
+   * @param {Item|null} right
    */
   constructor (left, right) {
     this.left = left
@@ -35,8 +35,8 @@ export class ItemListPosition {
 
 export class ItemTextListPosition extends ItemListPosition {
   /**
-   * @param {AbstractItem|null} left
+   * @param {Item|null} left
-   * @param {AbstractItem|null} right
+   * @param {Item|null} right
    * @param {Map<string,any>} currentAttributes
    */
   constructor (left, right, currentAttributes) {
@@ -47,8 +47,8 @@ export class ItemTextListPosition extends ItemListPosition {
 
 export class ItemInsertionResult extends ItemListPosition {
   /**
-   * @param {AbstractItem|null} left
+   * @param {Item|null} left
-   * @param {AbstractItem|null} right
+   * @param {Item|null} right
    * @param {Map<string,any>} negatedAttributes
    */
   constructor (left, right, negatedAttributes) {
@@ -61,8 +61,8 @@ export class ItemInsertionResult extends ItemListPosition {
  * @param {Transaction} transaction
  * @param {StructStore} store
  * @param {Map<string,any>} currentAttributes
- * @param {AbstractItem|null} left
+ * @param {Item|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} right
  * @param {number} count
  * @return {ItemTextListPosition}
  *
@@ -71,9 +71,9 @@ export class ItemInsertionResult extends ItemListPosition {
  */
 const findNextPosition = (transaction, store, currentAttributes, left, right, count) => {
   while (right !== null && count > 0) {
-    switch (right.constructor) {
+    switch (right.content.constructor) {
-      case ItemEmbed:
+      case ContentEmbed:
-      case ItemString:
+      case ContentString:
         if (!right.deleted) {
           if (count < right.length) {
             // split right
@@ -82,10 +82,9 @@ const findNextPosition = (transaction, store, currentAttributes, left, right, co
           count -= right.length
         }
         break
-      case ItemFormat:
+      case ContentFormat:
         if (!right.deleted) {
-          // @ts-ignore right is ItemFormat
+          updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (right.content))
-          updateCurrentAttributes(currentAttributes, right)
         }
         break
     }
@@ -117,8 +116,8 @@ const findPosition = (transaction, store, parent, index) => {
  *
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem|null} left
+ * @param {Item|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} right
  * @param {Map<string,any>} negatedAttributes
  * @return {ItemListPosition}
  *
@@ -130,21 +129,19 @@ const insertNegatedAttributes = (transaction, parent, left, right, negatedAttrib
   while (
     right !== null && (
       right.deleted === true || (
-        right.constructor === ItemFormat &&
+        right.content.constructor === ContentFormat &&
-        // @ts-ignore right is ItemFormat
+        (negatedAttributes.get(/** @type {ContentFormat} */ (right.content).key) === /** @type {ContentFormat} */ (right.content).value)
-        (negatedAttributes.get(right.key) === right.value)
       )
     )
   ) {
     if (!right.deleted) {
-      // @ts-ignore right is ItemFormat
+      negatedAttributes.delete(/** @type {ContentFormat} */ (right.content).key)
-      negatedAttributes.delete(right.key)
     }
     left = right
     right = right.right
   }
   for (let [key, val] of negatedAttributes) {
-    left = new ItemFormat(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, key, val)
+    left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentFormat(key, val))
     left.integrate(transaction)
   }
   return { left, right }
@@ -152,14 +149,13 @@ const insertNegatedAttributes = (transaction, parent, left, right, negatedAttrib
 
 /**
  * @param {Map<string,any>} currentAttributes
- * @param {ItemFormat} item
+ * @param {ContentFormat} format
  *
  * @private
  * @function
  */
-const updateCurrentAttributes = (currentAttributes, item) => {
+const updateCurrentAttributes = (currentAttributes, format) => {
-  const value = item.value
+  const { key, value } = format
-  const key = item.key
   if (value === null) {
     currentAttributes.delete(key)
   } else {
@@ -168,8 +164,8 @@ const updateCurrentAttributes = (currentAttributes, item) => {
 }
 
 /**
- * @param {AbstractItem|null} left
+ * @param {Item|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {Object<string,any>} attributes
  * @return {ItemListPosition}
@@ -184,11 +180,9 @@ const minimizeAttributeChanges = (left, right, currentAttributes, attributes) =>
       break
     } else if (right.deleted) {
       // continue
-    // @ts-ignore right is ItemFormat
+    } else if (right.content.constructor === ContentFormat && (attributes[(/** @type {ContentFormat} */ (right.content)).key] || null) === /** @type {ContentFormat} */ (right.content).value) {
-    } else if (right.constructor === ItemFormat && (attributes[right.key] || null) === right.value) {
       // found a format, update currentAttributes and continue
-      // @ts-ignore right is ItemFormat
+      updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (right.content))
-      updateCurrentAttributes(currentAttributes, right)
     } else {
       break
     }
@@ -201,8 +195,8 @@ const minimizeAttributeChanges = (left, right, currentAttributes, attributes) =>
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem|null} left
+ * @param {Item|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {Object<string,any>} attributes
  * @return {ItemInsertionResult}
@@ -219,7 +213,7 @@ const insertAttributes = (transaction, parent, left, right, currentAttributes, a
     if (currentVal !== val) {
       // save negated attribute (set null if currentVal undefined)
       negatedAttributes.set(key, currentVal)
-      left = new ItemFormat(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, key, val)
+      left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, new ContentFormat(key, val))
       left.integrate(transaction)
     }
   }
@@ -229,8 +223,8 @@ const insertAttributes = (transaction, parent, left, right, currentAttributes, a
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem|null} left
+ * @param {Item|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {string} text
  * @param {Object<string,any>} attributes
@@ -250,11 +244,8 @@ const insertText = (transaction, parent, left, right, currentAttributes, text, a
   left = insertPos.left
   right = insertPos.right
   // insert content
-  if (text.constructor === String) {
+  const content = text.constructor === String ? new ContentString(text) : new ContentEmbed(text)
-    left = new ItemString(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, text)
+  left = new Item(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, content)
-  } else {
-    left = new ItemEmbed(nextID(transaction), left, left === null ? null : left.lastId, right, right === null ? null : right.id, parent, null, text)
-  }
   left.integrate(transaction)
   return insertNegatedAttributes(transaction, parent, left, insertPos.right, insertPos.negatedAttributes)
 }
@@ -262,8 +253,8 @@ const insertText = (transaction, parent, left, right, currentAttributes, text, a
 /**
  * @param {Transaction} transaction
  * @param {AbstractType<any>} parent
- * @param {AbstractItem|null} left
+ * @param {Item|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {number} length
  * @param {Object<string,any>} attributes
@@ -282,26 +273,22 @@ const formatText = (transaction, parent, left, right, currentAttributes, length,
   // delete all formats with attributes[format.key] != null
   while (length > 0 && right !== null) {
     if (right.deleted === false) {
-      switch (right.constructor) {
+      switch (right.content.constructor) {
-        case ItemFormat:
+        case ContentFormat:
-          // @ts-ignore right is ItemFormat
+          const { key, value } = /** @type {ContentFormat} */ (right.content)
-          const attr = attributes[right.key]
+          const attr = attributes[key]
           if (attr !== undefined) {
-            // @ts-ignore right is ItemFormat
+            if (attr === value) {
-            if (attr === right.value) {
+              negatedAttributes.delete(key)
-              // @ts-ignore right is ItemFormat
-              negatedAttributes.delete(right.key)
             } else {
-              // @ts-ignore right is ItemFormat
+              negatedAttributes.set(key, value)
-              negatedAttributes.set(right.key, right.value)
             }
             right.delete(transaction)
           }
-          // @ts-ignore right is ItemFormat
+          updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (right.content))
-          updateCurrentAttributes(currentAttributes, right)
           break
-        case ItemEmbed:
+        case ContentEmbed:
-        case ItemString:
+        case ContentString:
           if (length < right.length) {
             getItemCleanStart(transaction, transaction.doc.store, createID(right.id.client, right.id.clock + length))
           }
@@ -317,8 +304,8 @@ const formatText = (transaction, parent, left, right, currentAttributes, length,
 
 /**
  * @param {Transaction} transaction
- * @param {AbstractItem|null} left
+ * @param {Item|null} left
- * @param {AbstractItem|null} right
+ * @param {Item|null} right
  * @param {Map<string,any>} currentAttributes
  * @param {number} length
  * @return {ItemListPosition}
@@ -329,13 +316,12 @@ const formatText = (transaction, parent, left, right, currentAttributes, length,
 const deleteText = (transaction, left, right, currentAttributes, length) => {
   while (length > 0 && right !== null) {
     if (right.deleted === false) {
-      switch (right.constructor) {
+      switch (right.content.constructor) {
-        case ItemFormat:
+        case ContentFormat:
-          // @ts-ignore right is ItemFormat
+          updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (right.content))
-          updateCurrentAttributes(currentAttributes, right)
           break
-        case ItemEmbed:
+        case ContentEmbed:
-        case ItemString:
+        case ContentString:
           if (length < right.length) {
             getItemCleanStart(transaction, transaction.doc.store, createID(right.id.client, right.id.clock + length))
           }
@@ -411,13 +397,10 @@ export class YTextEvent extends YEvent {
    */
   get delta () {
     if (this._delta === null) {
-      const y = this.target.doc
+      const y = /** @type {Doc} */ (this.target.doc)
-      // @ts-ignore
+      this._delta = []
       transact(y, transaction => {
-        /**
+        const delta = /** @type {Array<DeltaItem>} */ (this._delta)
-         * @type {Array<DeltaItem>}
-         */
-        const delta = []
         const currentAttributes = new Map() // saves all current attributes for insert
         const oldAttributes = new Map()
         let item = this.target._start
@@ -432,7 +415,6 @@ export class YTextEvent extends YEvent {
         let insert = ''
         let retain = 0
         let deleteLen = 0
-        this._delta = delta
         const addOp = () => {
           if (action !== null) {
             /**
@@ -472,14 +454,13 @@ export class YTextEvent extends YEvent {
           }
         }
         while (item !== null) {
-          switch (item.constructor) {
+          switch (item.content.constructor) {
-            case ItemEmbed:
+            case ContentEmbed:
               if (this.adds(item)) {
                 if (!this.deletes(item)) {
                   addOp()
                   action = 'insert'
-                  // @ts-ignore item is ItemFormat
+                  insert = /** @type {ContentEmbed} */ (item.content).embed
-                  insert = item.embed
                   addOp()
                 }
               } else if (this.deletes(item)) {
@@ -496,15 +477,14 @@ export class YTextEvent extends YEvent {
                 retain += 1
               }
               break
-            case ItemString:
+            case ContentString:
               if (this.adds(item)) {
                 if (!this.deletes(item)) {
                   if (action !== 'insert') {
                     addOp()
                     action = 'insert'
                   }
-                  // @ts-ignore
+                  insert += /** @type {ContentString} */ (item.content).str
-                  insert += item.string
                 }
               } else if (this.deletes(item)) {
                 if (action !== 'delete') {
@@ -520,59 +500,45 @@ export class YTextEvent extends YEvent {
                 retain += item.length
               }
               break
-            case ItemFormat:
+            case ContentFormat:
+              const { key, value } = /** @type {ContentFormat} */ (item.content)
               if (this.adds(item)) {
                 if (!this.deletes(item)) {
-                  // @ts-ignore item is ItemFormat
+                  const curVal = currentAttributes.get(key) || null
-                  const curVal = currentAttributes.get(item.key) || null
+                  if (curVal !== value) {
-                  // @ts-ignore item is ItemFormat
-                  if (curVal !== item.value) {
                     if (action === 'retain') {
                       addOp()
                     }
-                    // @ts-ignore item is ItemFormat
+                    if (value === (oldAttributes.get(key) || null)) {
-                    if (item.value === (oldAttributes.get(item.key) || null)) {
+                      delete attributes[key]
-                      // @ts-ignore item is ItemFormat
-                      delete attributes[item.key]
                     } else {
-                      // @ts-ignore item is ItemFormat
+                      attributes[key] = value
-                      attributes[item.key] = item.value
                     }
                   } else {
                     item.delete(transaction)
                   }
                 }
               } else if (this.deletes(item)) {
-                // @ts-ignore item is ItemFormat
+                oldAttributes.set(key, value)
-                oldAttributes.set(item.key, item.value)
+                const curVal = currentAttributes.get(key) || null
-                // @ts-ignore item is ItemFormat
+                if (curVal !== value) {
-                const curVal = currentAttributes.get(item.key) || null
-                // @ts-ignore item is ItemFormat
-                if (curVal !== item.value) {
                   if (action === 'retain') {
                     addOp()
                   }
-                  // @ts-ignore item is ItemFormat
+                  attributes[key] = curVal
-                  attributes[item.key] = curVal
                 }
               } else if (!item.deleted) {
-                // @ts-ignore item is ItemFormat
+                oldAttributes.set(key, value)
-                oldAttributes.set(item.key, item.value)
+                const attr = attributes[key]
-                // @ts-ignore item is ItemFormat
-                const attr = attributes[item.key]
                 if (attr !== undefined) {
-                  // @ts-ignore item is ItemFormat
+                  if (attr !== value) {
-                  if (attr !== item.value) {
                     if (action === 'retain') {
                       addOp()
                     }
-                    // @ts-ignore item is ItemFormat
+                    if (value === null) {
-                    if (item.value === null) {
+                      attributes[key] = value
-                      // @ts-ignore item is ItemFormat
-                      attributes[item.key] = item.value
                     } else {
-                      // @ts-ignore item is ItemFormat
+                      delete attributes[key]
-                      delete attributes[item.key]
                     }
                   } else {
                     item.delete(transaction)
@@ -583,26 +549,24 @@ export class YTextEvent extends YEvent {
                 if (action === 'insert') {
                   addOp()
                 }
-                // @ts-ignore item is ItemFormat
+                updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (item.content))
-                updateCurrentAttributes(currentAttributes, item)
               }
               break
           }
           item = item.right
         }
         addOp()
-        while (this._delta.length > 0) {
+        while (delta.length > 0) {
-          let lastOp = this._delta[this._delta.length - 1]
+          let lastOp = delta[delta.length - 1]
           if (lastOp.retain !== undefined && lastOp.attributes === undefined) {
             // retain delta's if they don't assign attributes
-            this._delta.pop()
+            delta.pop()
           } else {
             break
           }
         }
       })
     }
-    // @ts-ignore _delta is defined above
     return this._delta
   }
 }
@@ -636,15 +600,14 @@ export class YText extends AbstractType {
 
   /**
    * @param {Doc} y
-   * @param {ItemType} item
+   * @param {Item} item
    *
    * @private
    */
   _integrate (y, item) {
     super._integrate(y, item)
     try {
-      // @ts-ignore this._prelimContent is still defined
+      /** @type {Array<function>} */ (this._pending).forEach(f => f())
-      this._pending.forEach(f => f())
     } catch (e) {
       console.error(e)
     }
@@ -671,13 +634,12 @@ export class YText extends AbstractType {
   toString () {
     let str = ''
     /**
-     * @type {AbstractItem|null}
+     * @type {Item|null}
      */
     let n = this._start
     while (n !== null) {
-      if (!n.deleted && n.countable && n.constructor === ItemString) {
+      if (!n.deleted && n.countable && n.content.constructor === ContentString) {
-        // @ts-ignore
+        str += /** @type {ContentString} */ (n.content).str
-        str += n.string
       }
       n = n.right
     }
@@ -711,8 +673,7 @@ export class YText extends AbstractType {
         }
       })
     } else {
-      // @ts-ignore
+      /** @type {Array<function>} */ (this._pending).push(() => this.applyDelta(delta))
-      this._pending.push(() => this.applyDelta(delta))
     }
   }
 
@@ -732,10 +693,6 @@ export class YText extends AbstractType {
     const ops = []
     const currentAttributes = new Map()
     let str = ''
-    /**
-     * @type {AbstractItem|null}
-     */
-    // @ts-ignore
     let n = this._start
     function packStr () {
       if (str.length > 0) {
@@ -762,8 +719,8 @@ export class YText extends AbstractType {
     }
     while (n !== null) {
       if (isVisible(n, snapshot) || (prevSnapshot !== undefined && isVisible(n, prevSnapshot))) {
-        switch (n.constructor) {
+        switch (n.content.constructor) {
-          case ItemString:
+          case ContentString:
             const cur = currentAttributes.get('ychange')
             if (snapshot !== undefined && !isVisible(n, snapshot)) {
               if (cur === undefined || cur.user !== n.id.client || cur.state !== 'removed') {
@@ -779,20 +736,17 @@ export class YText extends AbstractType {
               packStr()
               currentAttributes.delete('ychange')
             }
-            // @ts-ignore
+            str += /** @type {ContentString} */ (n.content).str
-            str += n.string
             break
-          case ItemEmbed:
+          case ContentEmbed:
             packStr()
             ops.push({
-              // @ts-ignore item is ItemFormat
+              insert: /** @type {ContentEmbed} */ (n.content).embed
-              insert: n.embed
             })
             break
-          case ItemFormat:
+          case ContentFormat:
             packStr()
-            // @ts-ignore
+            updateCurrentAttributes(currentAttributes, /** @type {ContentFormat} */ (n.content))
-            updateCurrentAttributes(currentAttributes, n)
             break
         }
       }
@@ -823,8 +777,7 @@ export class YText extends AbstractType {
         insertText(transaction, this, left, right, currentAttributes, text, attributes)
       })
     } else {
-      // @ts-ignore
+      /** @type {Array<function>} */ (this._pending).push(() => this.insert(index, text, attributes))
-      this._pending.push(() => this.insert(index, text, attributes))
     }
   }
 
@@ -849,8 +802,7 @@ export class YText extends AbstractType {
         insertText(transaction, this, left, right, currentAttributes, embed, attributes)
       })
     } else {
-      // @ts-ignore
+      /** @type {Array<function>} */ (this._pending).push(() => this.insertEmbed(index, embed, attributes))
-      this._pending.push(() => this.insertEmbed(index, embed, attributes))
     }
   }
 
@@ -873,8 +825,7 @@ export class YText extends AbstractType {
         deleteText(transaction, left, right, currentAttributes, length)
       })
     } else {
-      // @ts-ignore
+      /** @type {Array<function>} */ (this._pending).push(() => this.delete(index, length))
-      this._pending.push(() => this.delete(index, length))
     }
   }
 
@@ -899,8 +850,7 @@ export class YText extends AbstractType {
         formatText(transaction, this, left, right, currentAttributes, length, attributes)
       })
     } else {
-      // @ts-ignore
+      /** @type {Array<function>} */ (this._pending).push(() => this.format(index, length, attributes))
-      this._pending.push(() => this.format(index, length, attributes))
     }
   }
 

src/types/YXmlElement.js

@@ -8,7 +8,7 @@ import {
   typeMapGetAll,
   typeListForEach,
   YXmlElementRefID,
-  Snapshot, Doc, ItemType // eslint-disable-line
+  Snapshot, Doc, Item // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -40,16 +40,14 @@ export class YXmlElement extends YXmlFragment {
    * * Observer functions are fired
    *
    * @param {Doc} y The Yjs instance
-   * @param {ItemType} item
+   * @param {Item} item
    * @private
    */
   _integrate (y, item) {
     super._integrate(y, item)
-    // @ts-ignore
+    this.insert(0, /** @type {Array} */ (this._prelimContent))
-    this.insert(0, this._prelimContent)
     this._prelimContent = null
-    // @ts-ignore
+    ;(/** @type {Map<string, any>} */ (this._prelimAttrs)).forEach((value, key) => {
-    this._prelimAttrs.forEach((value, key) => {
       this.setAttribute(key, value)
     })
     this._prelimContent = null
@@ -105,8 +103,7 @@ export class YXmlElement extends YXmlFragment {
         typeMapDelete(transaction, this, attributeName)
       })
     } else {
-      // @ts-ignore
+      /** @type {Map<string,any>} */ (this._prelimAttrs).delete(attributeName)
-      this._prelimAttrs.delete(attributeName)
     }
   }
 
@@ -124,8 +121,7 @@ export class YXmlElement extends YXmlFragment {
         typeMapSet(transaction, this, attributeName, attributeValue)
       })
     } else {
-      // @ts-ignore
+      /** @type {Map<string, any>} */ (this._prelimAttrs).set(attributeName, attributeValue)
-      this._prelimAttrs.set(attributeName, attributeValue)
     }
   }
 
@@ -139,8 +135,7 @@ export class YXmlElement extends YXmlFragment {
    * @public
    */
   getAttribute (attributeName) {
-    // @ts-ignore
+    return /** @type {any} */ (typeMapGet(this, attributeName))
-    return typeMapGet(this, attributeName)
   }
 
   /**

src/types/YXmlFragment.js

@@ -14,7 +14,7 @@ import {
   YXmlFragmentRefID,
   callTypeObservers,
   transact,
-  Transaction, ItemType, YXmlText, YXmlHook, Snapshot // eslint-disable-line
+  ContentType, Transaction, Item, YXmlText, YXmlHook, Snapshot // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -59,10 +59,9 @@ export class YXmlTreeWalker {
     this._filter = f
     this._root = root
     /**
-     * @type {ItemType | null}
+     * @type {Item}
      */
-    // @ts-ignore
+    this._currentNode = /** @type {Item} */ (root._start)
-    this._currentNode = root._start
     this._firstCall = true
   }
 
@@ -77,18 +76,21 @@ export class YXmlTreeWalker {
    * @public
    */
   next () {
+    /**
+     * @type {Item|null}
+     */
     let n = this._currentNode
-    if (n !== null && (!this._firstCall || n.deleted || !this._filter(n.type))) { // if first call, we check if we can use the first item
+    let type = /** @type {ContentType} */ (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 {
-        if (!n.deleted && (n.type.constructor === YXmlElement || n.type.constructor === YXmlFragment) && n.type._start !== null) {
+        type = /** @type {ContentType} */ (n.content).type
+        if (!n.deleted && (type.constructor === YXmlElement || type.constructor === YXmlFragment) && type._start !== null) {
           // walk down in the tree
-          // @ts-ignore
+          n = type._start
-          n = n.type._start
         } else {
           // walk right or up in the tree
           while (n !== null) {
             if (n.right !== null) {
-              // @ts-ignore
               n = n.right
               break
             } else if (n.parent === this._root) {
@@ -98,16 +100,15 @@ export class YXmlTreeWalker {
             }
           }
         }
-      } while (n !== null && (n.deleted || !this._filter(n.type)))
+      } while (n !== null && (n.deleted || !this._filter(/** @type {ContentType} */ (n.content).type)))
     }
     this._firstCall = false
-    this._currentNode = n
     if (n === null) {
-      // @ts-ignore return undefined if done=true (the expected result)
+      // @ts-ignore
       return { value: undefined, done: true }
     }
-    // @ts-ignore
+    this._currentNode = n
-    return { value: n.type, done: false }
+    return { value: /** @type {any} */ (n.content).type, done: false }
   }
 }
 

src/utils/DeleteSet.js

@@ -3,7 +3,8 @@ import {
   findIndexSS,
   createID,
   getState,
-  AbstractStruct, AbstractItem, StructStore, Transaction, ID // eslint-disable-line
+  splitItem,
+  Item, AbstractStruct, StructStore, Transaction, ID // eslint-disable-line
 } from '../internals.js'
 
 import * as math from 'lib0/math.js'
@@ -11,7 +12,7 @@ import * as map from 'lib0/map.js'
 import * as encoding from 'lib0/encoding.js'
 import * as decoding from 'lib0/decoding.js'
 
-class DeleteItem {
+export class DeleteItem {
   /**
    * @param {number} clock
    * @param {number} len
@@ -235,13 +236,13 @@ export const readDeleteSet = (decoder, transaction, store) => {
         let index = findIndexSS(structs, clock)
         /**
          * We can ignore the case of GC and Delete structs, because we are going to skip them
-         * @type {AbstractItem}
+         * @type {Item}
          */
         // @ts-ignore
         let struct = structs[index]
         // split the first item if necessary
         if (!struct.deleted && struct.id.clock < clock) {
-          structs.splice(index + 1, 0, struct.splitAt(transaction, clock - struct.id.clock))
+          structs.splice(index + 1, 0, splitItem(transaction, struct, clock - struct.id.clock))
           index++ // increase we now want to use the next struct
         }
         while (index < structs.length) {
@@ -250,7 +251,7 @@ export const readDeleteSet = (decoder, transaction, store) => {
           if (struct.id.clock < clock + len) {
             if (!struct.deleted) {
               if (clock + len < struct.id.clock + struct.length) {
-                structs.splice(index, 0, struct.splitAt(transaction, clock + len - struct.id.clock))
+                structs.splice(index, 0, splitItem(transaction, struct, clock + len - struct.id.clock))
               }
               struct.delete(transaction)
             }

src/utils/Doc.js

@@ -10,7 +10,7 @@ import {
   YMap,
   YXmlFragment,
   transact,
-  AbstractItem, Transaction, YEvent // eslint-disable-line
+  Item, Transaction, YEvent // eslint-disable-line
 } from '../internals.js'
 
 import { Observable } from 'lib0/observable.js'
@@ -97,7 +97,7 @@ export class Doc extends Observable {
         // @ts-ignore
         const t = new TypeConstructor()
         t._map = type._map
-        type._map.forEach(/** @param {AbstractItem?} n */ n => {
+        type._map.forEach(/** @param {Item?} n */ n => {
           for (; n !== null; n = n.left) {
             n.parent = t
           }

src/utils/RelativePosition.js

@@ -1,16 +1,15 @@
 
 import {
   getItem,
-  getItemType,
   createID,
   writeID,
   readID,
   compareIDs,
   getState,
   findRootTypeKey,
-  AbstractItem,
+  Item,
-  ItemType,
+  ContentType,
-  ID, StructStore, Doc, AbstractType // eslint-disable-line
+  ID, Doc, AbstractType // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
@@ -224,7 +223,7 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
       return null
     }
     const right = getItem(store, rightID)
-    if (!(right instanceof AbstractItem)) {
+    if (!(right instanceof Item)) {
       return null
     }
     index = right.deleted || !right.countable ? 0 : rightID.clock - right.id.clock
@@ -244,9 +243,9 @@ export const createAbsolutePositionFromRelativePosition = (rpos, doc) => {
         // type does not exist yet
         return null
       }
-      const struct = getItemType(store, typeID)
+      const struct = getItem(store, typeID)
-      if (struct instanceof ItemType) {
+      if (struct instanceof Item && struct.content instanceof ContentType) {
-        type = struct.type
+        type = struct.content.type
       } else {
         // struct is garbage collected
         return null

src/utils/Snapshot.js

@@ -1,7 +1,7 @@
 
 import {
   isDeleted,
-  DeleteSet, AbstractItem // eslint-disable-line
+  DeleteSet, Item // eslint-disable-line
 } from '../internals.js'
 
 export class Snapshot {
@@ -31,7 +31,7 @@ export class Snapshot {
 export const createSnapshot = (ds, sm) => new Snapshot(ds, sm)
 
 /**
- * @param {AbstractItem} item
+ * @param {Item} item
  * @param {Snapshot|undefined} snapshot
  *
  * @protected

src/utils/StructStore.js

@@ -1,7 +1,8 @@
 
 import {
   GC,
-  Transaction, AbstractStructRef, ID, ItemType, AbstractItem, AbstractStruct // eslint-disable-line
+  splitItem,
+  GCRef, ItemRef, Transaction, ID, Item, AbstractStruct // eslint-disable-line
 } from '../internals.js'
 
 import * as math from 'lib0/math.js'
@@ -21,14 +22,14 @@ export class StructStore {
      * We could shift the array of refs instead, but shift is incredible
      * slow in Chrome for arrays with more than 100k elements
      * @see tryResumePendingStructRefs
-     * @type {Map<number,{i:number,refs:Array<AbstractStructRef>}>}
+     * @type {Map<number,{i:number,refs:Array<GCRef|ItemRef>}>}
      * @private
      */
     this.pendingClientsStructRefs = new Map()
     /**
      * Stack of pending structs waiting for struct dependencies
      * Maximum length of stack is structReaders.size
-     * @type {Array<AbstractStructRef>}
+     * @type {Array<GCRef|ItemRef>}
      * @private
      */
     this.pendingStack = []
@@ -169,7 +170,7 @@ export const find = (store, id) => {
  *
  * @param {StructStore} store
  * @param {ID} id
- * @return {AbstractItem}
+ * @return {Item}
  *
  * @private
  * @function
@@ -177,43 +178,23 @@ export const find = (store, id) => {
 // @ts-ignore
 export const getItem = (store, id) => 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 {ItemType}
- *
- * @private
- * @function
- */
-// @ts-ignore
-export const getItemType = (store, id) => find(store, id)
-
 /**
  * Expects that id is actually in store. This function throws or is an infinite loop otherwise.
  *
  * @param {Transaction} transaction
  * @param {StructStore} store
  * @param {ID} id
- * @return {AbstractItem}
+ * @return {Item}
  *
  * @private
  * @function
  */
 export const getItemCleanStart = (transaction, store, id) => {
-  /**
+  const structs = /** @type {Array<Item>} */ (store.clients.get(id.client))
-   * @type {Array<AbstractItem>}
-   */
-  // @ts-ignore
-  const structs = store.clients.get(id.client)
   const index = findIndexSS(structs, id.clock)
-  /**
-   * @type {AbstractItem}
-   */
   let struct = structs[index]
   if (struct.id.clock < id.clock && struct.constructor !== GC) {
-    struct = struct.splitAt(transaction, id.clock - struct.id.clock)
+    struct = splitItem(transaction, struct, id.clock - struct.id.clock)
     structs.splice(index + 1, 0, struct)
   }
   return struct
@@ -225,21 +206,21 @@ export const getItemCleanStart = (transaction, store, id) => {
  * @param {Transaction} transaction
  * @param {StructStore} store
  * @param {ID} id
- * @return {AbstractItem}
+ * @return {Item}
  *
  * @private
  * @function
  */
 export const getItemCleanEnd = (transaction, store, id) => {
   /**
-   * @type {Array<AbstractItem>}
+   * @type {Array<Item>}
    */
   // @ts-ignore
   const structs = store.clients.get(id.client)
   const index = findIndexSS(structs, id.clock)
   const struct = structs[index]
   if (id.clock !== struct.id.clock + struct.length - 1 && struct.constructor !== GC) {
-    structs.splice(index + 1, 0, struct.splitAt(transaction, id.clock - struct.id.clock + 1))
+    structs.splice(index + 1, 0, splitItem(transaction, struct, id.clock - struct.id.clock + 1))
   }
   return struct
 }
@@ -254,10 +235,6 @@ export const getItemCleanEnd = (transaction, store, id) => {
  * @function
  */
 export const replaceStruct = (store, struct, newStruct) => {
-  /**
+  const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(struct.id.client))
-   * @type {Array<AbstractStruct>}
-   */
-  // @ts-ignore
-  const structs = store.clients.get(struct.id.client)
   structs[findIndexSS(structs, struct.id.clock)] = newStruct
 }

src/utils/Transaction.js

@@ -9,7 +9,7 @@ import {
   getStateVector,
   findIndexSS,
   callEventHandlerListeners,
-  AbstractItem,
+  Item,
   ID, AbstractType, AbstractStruct, YEvent, Doc // eslint-disable-line
 } from '../internals.js'
 
@@ -179,20 +179,15 @@ export const transact = (doc, f, origin = null) => {
           if (left.deleted === right.deleted && left.constructor === right.constructor) {
             if (left.mergeWith(right)) {
               structs.splice(pos, 1)
-              if (right instanceof AbstractItem && right.parentSub !== null && right.parent._map.get(right.parentSub) === right) {
+              if (right instanceof Item && right.parentSub !== null && right.parent._map.get(right.parentSub) === right) {
-                // @ts-ignore we already did a constructor check above
+                right.parent._map.set(right.parentSub, /** @type {Item} */ (left))
-                right.parent._map.set(right.parentSub, left)
               }
             }
           }
         }
         // replace deleted items with ItemDeleted / GC
         for (const [client, deleteItems] of ds.clients) {
-          /**
+          const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
-           * @type {Array<AbstractStruct>}
-           */
-          // @ts-ignore
-          const structs = store.clients.get(client)
           for (let di = deleteItems.length - 1; di >= 0; di--) {
             const deleteItem = deleteItems[di]
             const endDeleteItemClock = deleteItem.clock + deleteItem.len
@@ -205,7 +200,7 @@ export const transact = (doc, f, origin = null) => {
               if (deleteItem.clock + deleteItem.len <= struct.id.clock) {
                 break
               }
-              if (struct.deleted && struct instanceof AbstractItem) {
+              if (struct.deleted && struct instanceof Item) {
                 struct.gc(store, false)
               }
             }
@@ -214,11 +209,7 @@ export const transact = (doc, f, origin = null) => {
         // 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))
-           * @type {Array<AbstractStruct>}
-           */
-          // @ts-ignore
-          const structs = 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
@@ -237,11 +228,7 @@ export const transact = (doc, f, origin = null) => {
         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))
-             * @type {Array<AbstractStruct>}
-             */
-            // @ts-ignore
-            const structs = 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--) {
@@ -255,11 +242,7 @@ export const transact = (doc, f, origin = null) => {
         for (const mid of transaction._mergeStructs) {
           const client = mid.client
           const clock = mid.clock
-          /**
+          const structs = /** @type {Array<AbstractStruct>} */ (store.clients.get(client))
-           * @type {Array<AbstractStruct>}
-           */
-          // @ts-ignore
-          const structs = store.clients.get(client)
           const replacedStructPos = findIndexSS(structs, clock)
           if (replacedStructPos + 1 < structs.length) {
             tryToMergeWithLeft(structs, replacedStructPos + 1)

src/utils/UndoManager.js

@@ -200,4 +200,3 @@ export class UndoManager {
     return performedRedo
   }
 }
-}

src/utils/encoding.js

@@ -1,18 +1,23 @@
 
 /**
  * @module encoding
+ *
+ * We use the first five bits in the info flag for determining the type of the struct.
+ *
+ * 0: GC
+ * 1: Item with Deleted content
+ * 2: Item with JSON content
+ * 3: Item with Binary content
+ * 4: Item with String content
+ * 5: Item with Embed content (for richtext content)
+ * 6: Item with Format content (a formatting marker for richtext content)
+ * 7: Item with Type
  */
 
 import {
   findIndexSS,
   GCRef,
-  ItemBinaryRef,
+  ItemRef,
-  ItemDeletedRef,
-  ItemEmbedRef,
-  ItemFormatRef,
-  ItemJSONRef,
-  ItemStringRef,
-  ItemTypeRef,
   writeID,
   createID,
   readID,
@@ -21,27 +26,13 @@ import {
   readDeleteSet,
   writeDeleteSet,
   createDeleteSetFromStructStore,
-  Doc, Transaction, AbstractStruct, AbstractStructRef, StructStore, ID // eslint-disable-line
+  Doc, Transaction, AbstractStruct, StructStore, ID // eslint-disable-line
 } from '../internals.js'
 
 import * as encoding from 'lib0/encoding.js'
 import * as decoding from 'lib0/decoding.js'
 import * as binary from 'lib0/binary.js'
 
-/**
- * @private
- */
-export const structRefs = [
-  GCRef,
-  ItemBinaryRef,
-  ItemDeletedRef,
-  ItemEmbedRef,
-  ItemFormatRef,
-  ItemJSONRef,
-  ItemStringRef,
-  ItemTypeRef
-]
-
 /**
  * @param {encoding.Encoder} encoder
  * @param {Array<AbstractStruct>} structs All structs by `client`
@@ -68,19 +59,19 @@ const writeStructs = (encoder, structs, client, clock) => {
  * @param {decoding.Decoder} decoder
  * @param {number} numOfStructs
  * @param {ID} nextID
- * @return {Array<AbstractStructRef>}
+ * @return {Array<GCRef|ItemRef>}
  *
  * @private
  * @function
  */
 const readStructRefs = (decoder, numOfStructs, nextID) => {
   /**
-   * @type {Array<AbstractStructRef>}
+   * @type {Array<GCRef|ItemRef>}
    */
   const refs = []
   for (let i = 0; i < numOfStructs; i++) {
     const info = decoding.readUint8(decoder)
-    const ref = new structRefs[binary.BITS5 & info](decoder, nextID, info)
+    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)
   }
@@ -119,14 +110,14 @@ export const writeClientsStructs = (encoder, store, _sm) => {
 
 /**
  * @param {decoding.Decoder} decoder The decoder object to read data from.
- * @return {Map<number,Array<AbstractStructRef>>}
+ * @return {Map<number,Array<GCRef|ItemRef>>}
  *
  * @private
  * @function
  */
 export const readClientsStructRefs = decoder => {
   /**
-   * @type {Map<number,Array<AbstractStructRef>>}
+   * @type {Map<number,Array<GCRef|ItemRef>>}
    */
   const clientRefs = new Map()
   const numOfStateUpdates = decoding.readVarUint(decoder)
@@ -254,7 +245,7 @@ export const writeStructsFromTransaction = (encoder, transaction) => writeClient
 
 /**
  * @param {StructStore} store
- * @param {Map<number, Array<AbstractStructRef>>} clientsStructsRefs
+ * @param {Map<number, Array<GCRef|ItemRef>>} clientsStructsRefs
  *
  * @private
  * @function

tests/encoding.tests.js

@@ -1,36 +1,26 @@
 import * as t from 'lib0/testing.js'
 
 import {
-  structRefs,
+  contentRefs,
-  structGCRefNumber,
+  readContentBinary,
-  structBinaryRefNumber,
+  readContentDeleted,
-  structDeletedRefNumber,
+  readContentString,
-  structEmbedRefNumber,
+  readContentJSON,
-  structFormatRefNumber,
+  readContentEmbed,
-  structJSONRefNumber,
+  readContentType,
-  structStringRefNumber,
+  readContentFormat
-  structTypeRefNumber,
-  GCRef,
-  ItemBinaryRef,
-  ItemDeletedRef,
-  ItemEmbedRef,
-  ItemFormatRef,
-  ItemJSONRef,
-  ItemStringRef,
-  ItemTypeRef
 } from '../src/internals.js'
 
 /**
  * @param {t.TestCase} tc
  */
 export const testStructReferences = tc => {
-  t.assert(structRefs.length === 8)
+  t.assert(contentRefs.length === 8)
-  t.assert(structRefs[structGCRefNumber] === GCRef)
+  t.assert(contentRefs[1] === readContentDeleted)
-  t.assert(structRefs[structBinaryRefNumber] === ItemBinaryRef)
+  t.assert(contentRefs[2] === readContentJSON)
-  t.assert(structRefs[structDeletedRefNumber] === ItemDeletedRef)
+  t.assert(contentRefs[3] === readContentBinary)
-  t.assert(structRefs[structEmbedRefNumber] === ItemEmbedRef)
+  t.assert(contentRefs[4] === readContentString)
-  t.assert(structRefs[structFormatRefNumber] === ItemFormatRef)
+  t.assert(contentRefs[5] === readContentEmbed)
-  t.assert(structRefs[structJSONRefNumber] === ItemJSONRef)
+  t.assert(contentRefs[6] === readContentFormat)
-  t.assert(structRefs[structStringRefNumber] === ItemStringRef)
+  t.assert(contentRefs[7] === readContentType)
-  t.assert(structRefs[structTypeRefNumber] === ItemTypeRef)
 }

tests/testHelper.js

@@ -3,8 +3,8 @@ import * as Y from '../src/index.js'
 import {
   createDeleteSetFromStructStore,
   getStateVector,
-  AbstractItem,
+  Item,
-  DeleteSet, StructStore, Doc // eslint-disable-line
+  DeleteItem, DeleteSet, StructStore, Doc // eslint-disable-line
 } from '../src/internals.js'
 
 import * as t from 'lib0/testing.js'
@@ -12,6 +12,7 @@ import * as prng from 'lib0/prng.js'
 import * as encoding from 'lib0/encoding.js'
 import * as decoding from 'lib0/decoding.js'
 import * as syncProtocol from 'y-protocols/sync.js'
+export * from '../src/internals.js'
 
 /**
  * @param {TestYInstance} y // publish message created by `y` to all other online clients
@@ -240,8 +241,7 @@ export const init = (tc, { users = 5 } = {}, initTestObject) => {
   }
   testConnector.syncAll()
   result.testObjects = result.users.map(initTestObject || (() => null))
-  // @ts-ignore
+  return /** @type {any} */ (result)
-  return result
 }
 
 /**
@@ -282,8 +282,7 @@ export const compare = users => {
     t.compare(userArrayValues[i], userArrayValues[i + 1])
     t.compare(userMapValues[i], userMapValues[i + 1])
     t.compare(userXmlValues[i], userXmlValues[i + 1])
-    // @ts-ignore
+    t.compare(userTextValues[i].map(/** @param {any} a */ a => a.insert).join('').length, users[i].getText('text').length)
-    t.compare(userTextValues[i].map(a => a.insert).join('').length, users[i].getText('text').length)
     t.compare(userTextValues[i], userTextValues[i + 1])
     t.compare(getStateVector(users[i].store), getStateVector(users[i + 1].store))
     compareDS(createDeleteSetFromStructStore(users[i].store), createDeleteSetFromStructStore(users[i + 1].store))
@@ -293,8 +292,8 @@ export const compare = users => {
 }
 
 /**
- * @param {AbstractItem?} a
+ * @param {Item?} a
- * @param {AbstractItem?} b
+ * @param {Item?} b
  * @return {boolean}
  */
 export const compareItemIDs = (a, b) => a === b || (a !== null && b != null && Y.compareIDs(a.id, b.id))
@@ -306,11 +305,10 @@ export const compareItemIDs = (a, b) => a === b || (a !== null && b != null && Y
 export const compareStructStores = (ss1, ss2) => {
   t.assert(ss1.clients.size === ss2.clients.size)
   for (const [client, structs1] of ss1.clients) {
-    const structs2 = ss2.clients.get(client)
+    const structs2 = /** @type {Array<Y.AbstractStruct>} */ (ss2.clients.get(client))
     t.assert(structs2 !== undefined && structs1.length === structs2.length)
     for (let i = 0; i < structs1.length; i++) {
       const s1 = structs1[i]
-      // @ts-ignore
       const s2 = structs2[i]
       // checks for abstract struct
       if (
@@ -321,9 +319,9 @@ export const compareStructStores = (ss1, ss2) => {
       ) {
         t.fail('Structs dont match')
       }
-      if (s1 instanceof AbstractItem) {
+      if (s1 instanceof Item) {
         if (
-          !(s2 instanceof AbstractItem) ||
+          !(s2 instanceof Item) ||
           !((s1.left === null && s2.left === null) || (s1.left !== null && s2.left !== null && Y.compareIDs(s1.left.lastId, s2.left.lastId))) ||
           !compareItemIDs(s1.right, s2.right) ||
           !Y.compareIDs(s1.origin, s2.origin) ||
@@ -349,11 +347,10 @@ export const compareStructStores = (ss1, ss2) => {
 export const compareDS = (ds1, ds2) => {
   t.assert(ds1.clients.size === ds2.clients.size)
   for (const [client, deleteItems1] of ds1.clients) {
-    const deleteItems2 = ds2.clients.get(client)
+    const deleteItems2 = /** @type {Array<DeleteItem>} */ (ds2.clients.get(client))
     t.assert(deleteItems2 !== undefined && deleteItems1.length === deleteItems2.length)
     for (let i = 0; i < deleteItems1.length; i++) {
       const di1 = deleteItems1[i]
-      // @ts-ignore
       const di2 = deleteItems2[i]
       if (di1.clock !== di2.clock || di1.len !== di2.len) {
         t.fail('DeleteSets dont match')

tests/y-array.tests.js

@@ -1,4 +1,4 @@
-import { init, compare, applyRandomTests, TestYInstance } from './testHelper.js' // eslint-disable-line
+import { init, compare, applyRandomTests, Doc } from './testHelper.js' // eslint-disable-line
 
 import * as Y from '../src/index.js'
 import * as t from 'lib0/testing.js'
@@ -282,7 +282,7 @@ let _uniqueNumber = 0
 const getUniqueNumber = () => _uniqueNumber++
 
 /**
- * @type {Array<function(TestYInstance,prng.PRNG):void>}
+ * @type {Array<function(Doc,prng.PRNG,any):void>}
  */
 const arrayTransactions = [
   function insert (user, gen) {

tests/y-map.tests.js

@@ -1,4 +1,4 @@
-import { init, compare, applyRandomTests, TestYInstance } from './testHelper.js' // eslint-disable-line
+import { init, compare, applyRandomTests, Doc } from './testHelper.js' // eslint-disable-line
 
 import {
   compareIDs
@@ -328,7 +328,7 @@ export const testYmapEventHasCorrectValueWhenSettingAPrimitiveFromOtherUser = tc
 }
 
 /**
- * @type {Array<function(TestYInstance,prng.PRNG):void>}
+ * @type {Array<function(Doc,prng.PRNG):void>}
  */
 const mapTransactions = [
   function set (user, gen) {

tests/y-text.tests.js

@@ -63,7 +63,7 @@ export const testBasicFormat = tc => {
   t.compare(text0.toDelta(), [{ insert: 'zb', attributes: { bold: true } }])
   t.compare(delta, [{ insert: 'z', attributes: { bold: true } }])
   // @ts-ignore
-  t.assert(text0._start.right.right.right.string === 'b', 'Does not insert duplicate attribute marker')
+  t.assert(text0._start.right.right.right.content.str === 'b', 'Does not insert duplicate attribute marker')
   text0.insert(0, 'y')
   t.assert(text0.toString() === 'yzb')
   t.compare(text0.toDelta(), [{ insert: 'y' }, { insert: 'zb', attributes: { bold: true } }])
@@ -79,11 +79,11 @@ export const testBasicFormat = tc => {
  * @param {t.TestCase} tc
  */
 export const testGetDeltaWithEmbeds = tc => {
-  const { users, text0 } = init(tc, { users: 1 })
+  const { text0 } = init(tc, { users: 1 })
   text0.applyDelta([{
-    insert: {linebreak: "s"}
+    insert: {linebreak: 's'}
   }])
   t.compare(text0.toDelta(), [{
-    insert: {linebreak: "s"}
+    insert: {linebreak: 's'}
   }])
 }

tsconfig.json

@@ -36,8 +36,10 @@
 
     /* Module Resolution Options */
     "moduleResolution": "node",            /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
-    // "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
+    "baseUrl": "./",                       /* Base directory to resolve non-absolute module names. */
-    // "paths": {},                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
+    "paths": {
+      "yjs": ["./src/index.js"]
+    },                           /* A series of entries which re-map imports to lookup locations relative to the 'baseUrl'. */
     // "rootDirs": [],                        /* List of root folders whose combined content represents the structure of the project at runtime. */
     // "typeRoots": [],                       /* List of folders to include type definitions from. */
     // "types": [],                           /* Type declaration files to be included in compilation. */