loaded event when loaded from persistence adapter

src/Connector.js

@@ -132,6 +132,7 @@ export default class AbstractConnector {
         f()
       }
       this.whenSyncedListeners = []
+      this.y.loaded = true
       this.y.emit('synced')
     }
   }

src/Persistence.js

@@ -66,10 +66,12 @@ export default class AbstractPersistence {
     y.transact(function () {
       if (model != null) {
         fromBinary(y, new BinaryDecoder(new Uint8Array(model)))
+        y.loaded = true
       }
       if (updates != null) {
         for (let i = 0; i < updates.length; i++) {
           integrateRemoteStructs(y, new BinaryDecoder(new Uint8Array(updates[i])))
+          y.loaded = true
         }
       }
     })

src/Type/y-xml/YXmlFragment.js

@@ -185,6 +185,9 @@ export default class YXmlFragment extends YArray {
       this._dom._yxml = null
       this._dom = null
     }
+    if (this._beforeTransactionHandler !== undefined) {
+      this._y.off('beforeTransaction', this._beforeTransactionHandler)
+    }
   }
   insertDomElementsAfter (prev, doms, _document) {
     const types = domToYXml(this, doms, _document)
@@ -275,9 +278,10 @@ export default class YXmlFragment extends YArray {
     })
     // Apply Dom changes on Y.Xml
     if (typeof MutationObserver !== 'undefined') {
-      this._y.on('beforeTransaction', () => {
+      this._beforeTransactionHandler = () => {
         this._domObserverListener(this._domObserver.takeRecords())
-      })
+      }
+      this._y.on('beforeTransaction', this._beforeTransactionHandler)
       this._domObserverListener = mutations => {
         this._mutualExclude(() => {
           this._y.transact(() => {

src/Util/NamedEventHandler.js

@@ -27,7 +27,8 @@ export default class NamedEventHandler {
     }
     const listener = this._eventListener.get(name)
     if (listener !== undefined) {
-      listener.remove(f)
+      listener.on.delete(f)
+      listener.once.delete(f)
     }
   }
   emit (name, ...args) {

src/Y.js

@@ -21,9 +21,12 @@ import { addStruct as addType } from './Util/structReferences.js'
 import debug from 'debug'
 import Transaction from './Transaction.js'
 
+import YIndexedDB from '../../y-indexeddb/src/y-indexeddb.js'
+
 export default class Y extends NamedEventHandler {
   constructor (opts, persistence) {
     super()
+    this._loaded = false
     this._opts = opts
     this.userID = opts._userID != null ? opts._userID : generateUserID()
     this.share = {}
@@ -47,6 +50,15 @@ export default class Y extends NamedEventHandler {
       initConnection()
     }
   }
+  get loaded () {
+    return this._loaded
+  }
+  set loaded (val) {
+    if (this._loaded === false && val) {
+      this._loaded = true
+      this.emit('loaded')
+    }
+  }
   _beforeChange () {}
   transact (f, remote = false) {
     let initialCall = this._transaction === null