add function to create lots of rooms

add client-server updateCounter support to sync all persisted rooms
save current state at the beginning in YIndexedDB
2018-06-07 16:36:42 +02:00 · 2018-06-04 17:35:39 +02:00 · 2018-06-03 22:39:22 +02:00 · 2018-06-03 21:58:51 +02:00 · 2018-06-02 22:16:12 +02:00 · 2018-06-02 13:33:04 +02:00
145 changed files with 9301 additions and 4885 deletions
--- a/.esdoc.json
+++ b/.esdoc.json
@@ -0,0 +1,10 @@
+{
+  "source": "./src",
+  "destination": "./docs",
+  "plugins": [{
+    "name": "esdoc-standard-plugin",
+    "option": {
+      "accessor": {"access": ["public"], "autoPrivate": true}
+    }
+  }]
+}
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,7 @@
 node_modules
 bower_components
+docs
 /y.*
 /examples/yjs-dist.js*
+.vscode
+.yjsPersisted
--- a/README.md
+++ b/README.md
@@ -64,6 +64,18 @@ missing modules.
 <script src="./bower_components/yjs/y.js"></script>
 ```

+### CDN
+```
+<script src="https://cdn.jsdelivr.net/npm/yjs@12/src/y.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-array@10/dist/y-array.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-websockets-client@8/dist/y-websockets-client.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-memory@8/dist/y-memory.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-map@10/dist/y-map.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/y-text@9/dist/y-text.js"></script>
+// ..
+// do the same for all modules you want to use
+```
+
 ### Npm
 ```
 npm install --save yjs % add all y-* modules you want to use
@@ -76,7 +88,6 @@ var Y = require('yjs')
 require('y-array')(Y) // add the y-array type to Yjs
 require('y-websockets-client')(Y)
 require('y-memory')(Y)
-require('y-array')(Y)
 require('y-map')(Y)
 require('y-text')(Y)
 // ..
@@ -89,7 +100,6 @@ import Y from 'yjs'
 import yArray from 'y-array'
 import yWebsocketsClient from 'y-webrtc'
 import yMemory from 'y-memory'
-import yArray from 'y-array'
 import yMap from 'y-map'
 import yText from 'y-text'
 // ..
--- a/examples/ace/index.html
+++ b/examples/ace/index.html
@@ -24,7 +24,8 @@
  <body>

    <div id="aceContainer"></div>
-    <script src="../bower_components/yjs/y.js"></script>
+    <script src="../../y.js"></script>
+    <script src='../../../y-websockets-client/y-websockets-client.js'></script>
    <script src="../bower_components/ace-builds/src/ace.js"></script>

    <script src="./index.js"></script>
--- a/examples/ace/index.js
+++ b/examples/ace/index.js
@@ -1,24 +1,17 @@
 /* global Y, ace */

-Y({
-  db: {
-    name: 'memory'
-  },
+let y = new Y('ace-example', {
  connector: {
    name: 'websockets-client',
-    room: 'ace-example'
-  },
-  sourceDir: '/bower_components',
-  share: {
-    ace: 'Text' // y.share.textarea is of type Y.Text
+    url: 'http://127.0.0.1:1234'
  }
-}).then(function (y) {
-  window.yAce = y
-
-  // bind the textarea to a shared text element
-  var editor = ace.edit('aceContainer')
-  editor.setTheme('ace/theme/chrome')
-  editor.getSession().setMode('ace/mode/javascript')
-
-  y.share.ace.bindAce(editor)
 })
+
+window.yAce = y
+
+// bind the textarea to a shared text element
+var editor = ace.edit('aceContainer')
+editor.setTheme('ace/theme/chrome')
+editor.getSession().setMode('ace/mode/javascript')
+
+y.define('ace', Y.Text).bindAce(editor)
--- a/examples/chat/index.html
+++ b/examples/chat/index.html
@@ -13,7 +13,7 @@
      <input type="submit" value="Send">
    </form>
    <script src="../../y.js"></script>
-    <script src="../../../y-websockets-client/dist/y-websockets-client.js"></script>
+    <script src='../../../y-websockets-client/y-websockets-client.js'></script>
    <script src="./index.js"></script>
  </body>
 </html>
--- a/examples/chat/index.js
+++ b/examples/chat/index.js
@@ -1,10 +1,9 @@
 /* global Y */

-// initialize a shared object. This function call returns a promise!
-var y = new Y({
+let y = new Y('chat-example', {
  connector: {
    name: 'websockets-client',
-    room: 'chat-example'
+    url: 'http://127.0.0.1:1234'
  }
 })

@@ -23,6 +22,7 @@ function appendMessage (message, position) {
  p.appendChild(document.createTextNode(message.message))
  chatcontainer.insertBefore(p, chatcontainer.children[position] || null)
 }
+
 // This function makes sure that only 7 messages exist in the chat history.
 // The rest is deleted
 function cleanupChat () {
@@ -30,23 +30,17 @@ function cleanupChat () {
    chatprotocol.delete(0, chatprotocol.length - 7)
  }
 }
+cleanupChat()
+
 // Insert the initial content
 chatprotocol.toArray().forEach(appendMessage)
-cleanupChat()

 // whenever content changes, make sure to reflect the changes in the DOM
 chatprotocol.observe(function (event) {
-  if (event.type === 'insert') {
-    for (let i = 0; i < event.length; i++) {
-      appendMessage(event.values[i], event.index + i)
-    }
-  } else if (event.type === 'delete') {
-    for (let i = 0; i < event.length; i++) {
-      chatcontainer.children[event.index].remove()
-    }
-  }
  // concurrent insertions may result in a history > 7, so cleanup here
  cleanupChat()
+  chatcontainer.innerHTML = ''
+  chatprotocol.toArray().forEach(appendMessage)
 })
 document.querySelector('#chatform').onsubmit = function (event) {
  // the form is submitted
--- a/examples/codemirror/index.html
+++ b/examples/codemirror/index.html
@@ -5,7 +5,8 @@
  <body>
    <div id="codeMirrorContainer"></div>

-    <script src="../bower_components/yjs/y.js"></script>
+    <script src="../../y.js"></script>
+    <script src='../../../y-websockets-client/y-websockets-client.js'></script>
    <script src="../bower_components/codemirror/lib/codemirror.js"></script>
    <script src="../bower_components/codemirror/mode/javascript/javascript.js"></script>
    <link rel="stylesheet" href="../bower_components/codemirror/lib/codemirror.css">
--- a/examples/codemirror/index.js
+++ b/examples/codemirror/index.js
@@ -1,24 +1,16 @@
 /* global Y, CodeMirror */

-// initialize a shared object. This function call returns a promise!
-Y({
-  db: {
-    name: 'memory'
-  },
+let y = new Y('codemirror-example', {
  connector: {
    name: 'websockets-client',
-    room: 'codemirror-example'
-  },
-  sourceDir: '/bower_components',
-  share: {
-    codemirror: 'Text' // y.share.codemirror is of type Y.Text
+    url: 'http://127.0.0.1:1234'
  }
-}).then(function (y) {
-  window.yCodeMirror = y
-
-  var editor = CodeMirror(document.querySelector('#codeMirrorContainer'), {
-    mode: 'javascript',
-    lineNumbers: true
-  })
-  y.share.codemirror.bindCodeMirror(editor)
 })
+
+window.yCodeMirror = y
+
+var editor = CodeMirror(document.querySelector('#codeMirrorContainer'), {
+  mode: 'javascript',
+  lineNumbers: true
+})
+y.define('codemirror', Y.Text).bindCodeMirror(editor)
--- a/examples/drawing/index.html
+++ b/examples/drawing/index.html
@@ -13,11 +13,8 @@
  <button type="button" id="clearDrawingCanvas">Clear Drawing</button>
  <svg id="drawingCanvas" viewbox="0 0 100 100" width="100%"></svg>
  <script src="../../y.js"></script>
-  <script src="../../../y-array/y-array.js"></script>
-  <script src="../../../y-map/dist/y-map.js"></script>
-  <script src="../../../y-memory/y-memory.js"></script>
-  <script src="../../../y-websockets-client/y-websockets-client.js"></script>
-  <script src="../bower_components/d3/d3.js"></script>
+  <script src='../../../y-websockets-client/y-websockets-client.js'></script>
+  <script src="../bower_components/d3/d3.min.js"></script>
  <script src="./index.js"></script>
 </body>
 </html>
--- a/examples/drawing/index.js
+++ b/examples/drawing/index.js
@@ -1,84 +1,74 @@
 /* globals Y, d3 */
-'strict mode'

-Y({
-  db: {
-    name: 'memory'
-  },
+let y = new Y('drawing-example', {
  connector: {
    name: 'websockets-client',
-    room: 'drawing-example',
-    url: 'localhost:1234'
-  },
-  sourceDir: '/bower_components',
-  share: {
-    drawing: 'Array'
-  }
-}).then(function (y) {
-  window.yDrawing = y
-  var drawing = y.share.drawing
-  var renderPath = d3.svg.line()
-    .x(function (d) { return d[0] })
-    .y(function (d) { return d[1] })
-    .interpolate('basis')
-
-  var svg = d3.select('#drawingCanvas')
-    .call(d3.behavior.drag()
-      .on('dragstart', dragstart)
-      .on('drag', drag)
-      .on('dragend', dragend))
-
-  // create line from a shared array object and update the line when the array changes
-  function drawLine (yarray) {
-    var line = svg.append('path').datum(yarray.toArray())
-    line.attr('d', renderPath)
-    yarray.observe(function (event) {
-      // we only implement insert events that are appended to the end of the array
-      event.values.forEach(function (value) {
-        line.datum().push(value)
-      })
-      line.attr('d', renderPath)
-    })
-  }
-  // call drawLine every time an array is appended
-  y.share.drawing.observe(function (event) {
-    if (event.type === 'insert') {
-      event.values.forEach(drawLine)
-    } else {
-      // just remove all elements (thats what we do anyway)
-      svg.selectAll('path').remove()
-    }
-  })
-  // draw all existing content
-  for (var i = 0; i < drawing.length; i++) {
-    drawLine(drawing.get(i))
-  }
-
-  // clear canvas on request
-  document.querySelector('#clearDrawingCanvas').onclick = function () {
-    drawing.delete(0, drawing.length)
-  }
-
-  var sharedLine = null
-  function dragstart () {
-    drawing.insert(drawing.length, [Y.Array])
-    sharedLine = drawing.get(drawing.length - 1)
-  }
-
-  // After one dragged event is recognized, we ignore them for 33ms.
-  var ignoreDrag = null
-  function drag () {
-    if (sharedLine != null && ignoreDrag == null) {
-      ignoreDrag = window.setTimeout(function () {
-        ignoreDrag = null
-      }, 33)
-      sharedLine.push([d3.mouse(this)])
-    }
-  }
-
-  function dragend () {
-    sharedLine = null
-    window.clearTimeout(ignoreDrag)
-    ignoreDrag = null
+    url: 'http://127.0.0.1:1234'
  }
 })
+
+window.yDrawing = y
+var drawing = y.define('drawing', Y.Array)
+var renderPath = d3.svg.line()
+  .x(function (d) { return d[0] })
+  .y(function (d) { return d[1] })
+  .interpolate('basic')
+
+var svg = d3.select('#drawingCanvas')
+  .call(d3.behavior.drag()
+    .on('dragstart', dragstart)
+    .on('drag', drag)
+    .on('dragend', dragend))
+
+// create line from a shared array object and update the line when the array changes
+function drawLine (yarray) {
+  var line = svg.append('path').datum(yarray.toArray())
+  line.attr('d', renderPath)
+  yarray.observe(function (event) {
+    line.remove()
+    line = svg.append('path').datum(yarray.toArray())
+    line.attr('d', renderPath)
+  })
+}
+// call drawLine every time an array is appended
+drawing.observe(function (event) {
+  event.removedElements.forEach(function () {
+    // if one is deleted, all will be deleted!!
+    svg.selectAll('path').remove()
+  })
+  event.addedElements.forEach(function (path) {
+    drawLine(path)
+  })
+})
+// draw all existing content
+for (var i = 0; i < drawing.length; i++) {
+  drawLine(drawing.get(i))
+}
+
+// clear canvas on request
+document.querySelector('#clearDrawingCanvas').onclick = function () {
+  drawing.delete(0, drawing.length)
+}
+
+var sharedLine = null
+function dragstart () {
+  drawing.insert(drawing.length, [Y.Array])
+  sharedLine = drawing.get(drawing.length - 1)
+}
+
+// After one dragged event is recognized, we ignore them for 33ms.
+var ignoreDrag = null
+function drag () {
+  if (sharedLine != null && ignoreDrag == null) {
+    ignoreDrag = window.setTimeout(function () {
+      ignoreDrag = null
+    }, 10)
+    sharedLine.push([d3.mouse(this)])
+  }
+}
+
+function dragend () {
+  sharedLine = null
+  window.clearTimeout(ignoreDrag)
+  ignoreDrag = null
+}
--- a/examples/html-editor-drawing-hook/index.html
+++ b/examples/html-editor-drawing-hook/index.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<html>
+</head>
+  <script src="../../y.js"></script>
+  <script src='../../../y-websockets-client/y-websockets-client.js'></script>
+  <script src="../bower_components/d3/d3.min.js"></script>
+  <script src="./index.js"></script>
+  <style>
+    magic-drawing .drawingCanvas path {
+      fill: none;
+      stroke: blue;
+      stroke-width: 2px;
+      stroke-linejoin: round;
+      stroke-linecap: round;
+    }
+    magic-drawing .drawingCanvas {
+      width: 500px;
+      height: 500px;
+      cursor: default;
+      padding:1px;
+      border:1px solid #021a40;
+    }
+    magic-drawing .clearDrawingButton {
+      position: absolute;
+      top: 0;
+      left: 0;
+    }
+    magic-drawing {
+      position: relative;
+      display: block;
+    }
+  </style>
+</head>
+<body contenteditable="true">
+</body>
+</html>
--- a/examples/html-editor-drawing-hook/index.js
+++ b/examples/html-editor-drawing-hook/index.js
@@ -0,0 +1,134 @@
+/* global Y, d3 */
+
+const hooks = {
+  'magic-drawing': {
+    fillType: function (dom, type) {
+      initDrawingBindings(type, dom)
+    },
+    createDom: function (type) {
+      const dom = document.createElement('magic-drawing')
+      initDrawingBindings(type, dom)
+      return dom
+    }
+  }
+}
+
+window.onload = function () {
+  window.domBinding = new Y.DomBinding(window.yXmlType, document.body, { hooks })
+}
+
+window.addMagicDrawing = function addMagicDrawing () {
+  let mt = document.createElement('magic-drawing')
+  mt.setAttribute('data-yjs-hook', 'magic-drawing')
+  document.body.append(mt)
+}
+
+var renderPath = d3.svg.line()
+  .x(function (d) { return d[0] })
+  .y(function (d) { return d[1] })
+  .interpolate('basic')
+
+function initDrawingBindings (type, dom) {
+  dom.contentEditable = 'false'
+  dom.setAttribute('data-yjs-hook', 'magic-drawing')
+  var drawing = type.get('drawing')
+  if (drawing === undefined) {
+    drawing = type.set('drawing', new Y.Array())
+  }
+  var canvas = dom.querySelector('.drawingCanvas')
+  if (canvas == null) {
+    canvas = document.createElementNS('http://www.w3.org/2000/svg', 'svg')
+    canvas.setAttribute('class', 'drawingCanvas')
+    canvas.setAttribute('viewbox', '0 0 100 100')
+    dom.insertBefore(canvas, null)
+  }
+  var clearDrawingButton = dom.querySelector('.clearDrawingButton')
+  if (clearDrawingButton == null) {
+    clearDrawingButton = document.createElement('button')
+    clearDrawingButton.setAttribute('type', 'button')
+    clearDrawingButton.setAttribute('class', 'clearDrawingButton')
+    clearDrawingButton.innerText = 'Clear Drawing'
+    dom.insertBefore(clearDrawingButton, null)
+  }
+  var svg = d3.select(canvas)
+    .call(d3.behavior.drag()
+      .on('dragstart', dragstart)
+      .on('drag', drag)
+      .on('dragend', dragend))
+  // create line from a shared array object and update the line when the array changes
+  function drawLine (yarray, svg) {
+    var line = svg.append('path').datum(yarray.toArray())
+    line.attr('d', renderPath)
+    yarray.observe(function (event) {
+      line.remove()
+      line = svg.append('path').datum(yarray.toArray())
+      line.attr('d', renderPath)
+    })
+  }
+  // call drawLine every time an array is appended
+  drawing.observe(function (event) {
+    event.removedElements.forEach(function () {
+      // if one is deleted, all will be deleted!!
+      svg.selectAll('path').remove()
+    })
+    event.addedElements.forEach(function (path) {
+      drawLine(path, svg)
+    })
+  })
+  // draw all existing content
+  for (var i = 0; i < drawing.length; i++) {
+    drawLine(drawing.get(i), svg)
+  }
+
+  // clear canvas on request
+  clearDrawingButton.onclick = function () {
+    drawing.delete(0, drawing.length)
+  }
+
+  var sharedLine = null
+  function dragstart () {
+    drawing.insert(drawing.length, [Y.Array])
+    sharedLine = drawing.get(drawing.length - 1)
+  }
+
+  // After one dragged event is recognized, we ignore them for 33ms.
+  var ignoreDrag = null
+  function drag () {
+    if (sharedLine != null && ignoreDrag == null) {
+      ignoreDrag = window.setTimeout(function () {
+        ignoreDrag = null
+      }, 10)
+      sharedLine.push([d3.mouse(this)])
+    }
+  }
+
+  function dragend () {
+    sharedLine = null
+    window.clearTimeout(ignoreDrag)
+    ignoreDrag = null
+  }
+}
+
+let y = new Y('html-editor-drawing-hook-example', {
+  connector: {
+    name: 'websockets-client',
+    url: 'http://127.0.0.1:1234'
+  }
+})
+
+window.yXml = y
+window.yXmlType = y.define('xml', Y.XmlFragment)
+window.undoManager = new Y.utils.UndoManager(window.yXmlType, {
+  captureTimeout: 500
+})
+
+document.onkeydown = function interceptUndoRedo (e) {
+  if (e.keyCode === 90 && e.metaKey) {
+    if (!e.shiftKey) {
+      window.undoManager.undo()
+    } else {
+      window.undoManager.redo()
+    }
+    e.preventDefault()
+  }
+}
--- a/examples/html-editor/index.html
+++ b/examples/html-editor/index.html
@@ -1,11 +1,11 @@
 <!DOCTYPE html>
 <html>
 </head>
-  <!-- jquery is not required for y-xml. It is just here for convenience, and to test batch operations. -->
-  <script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
-  <script src="../yjs-dist.js"></script>
-  <script src="./index.js"></script>
+  <script src="./index.mjs" type="module"></script>
 </head>
-<body contenteditable="true">
+<body>
+    <label for="room">Room: </label>
+    <input type="text" id="room" name="room">
+    <div id="content" contenteditable style="position:absolute;top:35px;left:0;right:0;bottom:0;outline: 0px solid transparent;"></div>
 </body>
 </html>
--- a/examples/html-editor/index.js
+++ b/examples/html-editor/index.js
@@ -1,43 +0,0 @@
-/* global Y, HTMLElement, customElements */
-
-class MagicTable extends HTMLElement {
-  constructor () {
-    super()
-    var shadow = this.attachShadow({mode: 'open'})
-    setTimeout(() => {
-      shadow.append(this.childNodes[0])
-    }, 1000)
-  }
-}
-customElements.define('magic-table', MagicTable)
-
-// initialize a shared object. This function call returns a promise!
-let y = new Y({
-  connector: {
-    name: 'websockets-client',
-    url: 'http://127.0.0.1:1234',
-    room: 'html-editor-example6'
-    // maxBufferLength: 100
-  }
-})
-window.yXml = y
-window.yXmlType = y.define('xml', Y.XmlFragment)
-window.onload = function () {
-  console.log('start!')
-  // Bind children of XmlFragment to the document.body
-  window.yXmlType.bindToDom(document.body)
-}
-window.undoManager = new Y.utils.UndoManager(window.yXmlType, {
-  captureTimeout: 500
-})
-
-document.onkeydown = function interceptUndoRedo (e) {
-  if (e.keyCode === 90 && e.metaKey) {
-    if (!e.shiftKey) {
-      window.undoManager.undo()
-    } else {
-      window.undoManager.redo()
-    }
-    e.preventDefault()
-  }
-}
--- a/examples/html-editor/index.mjs
+++ b/examples/html-editor/index.mjs
@@ -0,0 +1,77 @@
+
+import YWebsocketsConnector from '../../src/Connectors/WebsocketsConnector/WebsocketsConnector.mjs'
+import Y from '../../src/Y.mjs'
+import DomBinding from '../../src/Bindings/DomBinding/DomBinding.mjs'
+import UndoManager from '../../src/Util/UndoManager.mjs'
+import YXmlFragment from '../../src/Types/YXml/YXmlFragment.mjs'
+import YXmlText from '../../src/Types/YXml/YXmlText.mjs'
+import YXmlElement from '../../src/Types/YXml/YXmlElement.mjs'
+import YIndexdDBPersistence from '../../src/Persistences/IndexedDBPersistence.mjs'
+
+const connector = new YWebsocketsConnector()
+const persistence = new YIndexdDBPersistence()
+
+const roomInput = document.querySelector('#room')
+
+let currentRoomName = null
+let y = null
+let domBinding = null
+
+function setRoomName (roomName) {
+  if (currentRoomName !== roomName) {
+    console.log(`change room: "${roomName}"`)
+    roomInput.value = roomName
+    currentRoomName = roomName
+    location.hash = '#' + roomName
+    if (y !== null) {
+      domBinding.destroy()
+    }
+
+    const room = connector._rooms.get(roomName)
+    if (room !== undefined) {
+      y = room.y
+    } else {
+      y = new Y(roomName, null, null, { gc: true })
+      persistence.connectY(roomName, y).then(() => {
+        // connect after persisted content was applied to y
+        // If we don't wait for persistence, the other peer will send all data, waisting
+        // network bandwidth..
+        connector.connectY(roomName, y)
+      })
+      window.y = y
+    }
+
+    window.y = y
+    window.yXmlType = y.define('xml', YXmlFragment)
+
+    domBinding = new DomBinding(window.yXmlType, document.querySelector('#content'), { scrollingElement: document.scrollingElement })
+  }
+}
+window.setRoomName = setRoomName
+
+window.createRooms = function (i = 0) {
+  setInterval(function () {
+    setRoomName(i + '')
+    i++
+    const nodes = []
+    for (let j = 0; j < 100; j++) {
+      const node = new YXmlElement('p')
+      node.insert(0, [new YXmlText(`This is the ${i}th paragraph of room ${i}`)])
+      nodes.push(node)
+    }
+    y.share.xml.insert(0, nodes)
+  }, 100)
+}
+
+connector.syncPersistence(persistence)
+
+window.connector = connector
+window.persistence = persistence
+
+window.onload = function () {
+  setRoomName((location.hash || '#default').slice(1))
+  roomInput.addEventListener('input', e => {
+    const roomName = e.target.value
+    setRoomName(roomName)
+  })
+}
--- a/examples/indexeddb/index.html
+++ b/examples/indexeddb/index.html
@@ -16,6 +16,9 @@
        width: 100%;
      }
    </style>
-    <script type="module" src="./index.js"></script>
+    <script src="../../y.js"></script>
+    <script src='../../../y-websockets-client/y-websockets-client.js'></script>
+    <script src='../../../y-indexeddb/y-indexeddb.js'></script>
+    <script src="./index.js"></script>
  </body>
 </html>
--- a/examples/indexeddb/index.js
+++ b/examples/indexeddb/index.js
@@ -1,24 +1,19 @@
 /* global Y, CodeMirror */

-// initialize a shared object. This function call returns a promise!
-Y({
-  db: {
-    name: 'memory'
-  },
+const persistence = new Y.IndexedDB()
+const connector = {
  connector: {
    name: 'websockets-client',
    room: 'codemirror-example'
-  },
-  sourceDir: '/bower_components',
-  share: {
-    codemirror: 'Text' // y.share.codemirror is of type Y.Text
  }
-}).then(function (y) {
-  window.yCodeMirror = y
+}

-  var editor = CodeMirror(document.querySelector('#codeMirrorContainer'), {
-    mode: 'javascript',
-    lineNumbers: true
-  })
-  y.share.codemirror.bindCodeMirror(editor)
+const y = new Y('codemirror-example', connector, persistence)
+window.yCodeMirror = y
+
+var editor = CodeMirror(document.querySelector('#codeMirrorContainer'), {
+  mode: 'javascript',
+  lineNumbers: true
 })
+
+y.define('codemirror', Y.Text).bindCodeMirror(editor)
--- a/examples/infiniteyjs/index.html
+++ b/examples/infiniteyjs/index.html
@@ -10,7 +10,7 @@
    .one {
      grid-column: 1 ;
    }
-    .two { 
+    .two {
      grid-column: 2;
    }
    .three {
@@ -49,10 +49,7 @@
    </div>
  </div>
  <script src="../../y.js"></script>
-  <script src="../../../y-array/y-array.js"></script>
-  <script src="../../../y-text/dist/y-text.js"></script>
-  <script src="../../../y-memory/y-memory.js"></script>
-  <script src="../../../y-websockets-client/y-websockets-client.js"></script>
+  <script src='../../../y-websockets-client/y-websockets-client.js'></script>
  <script src="./index.js"></script>
 </body>
 </html>
--- a/examples/infiniteyjs/index.js
+++ b/examples/infiniteyjs/index.js
@@ -1,64 +1,38 @@
 /* global Y */

-Y({
-  db: {
-    name: 'memory'
-  },
-  connector: {
-    name: 'websockets-client',
-    room: 'Textarea-example',
-    url: 'https://yjs-v13.herokuapp.com/'
-  },
-  share: {
-    textarea: 'Text'
-  }
-}).then(function (y) {
-  window.y1 = y
-  y.share.textarea.bind(document.getElementById('textarea1'))
-})
-
-Y({
-  db: {
-    name: 'memory'
-  },
-  connector: {
-    name: 'websockets-client',
-    room: 'Textarea-example',
-    url: 'https://yjs-v13-second.herokuapp.com/'
-  },
-  share: {
-    textarea: 'Text'
-  }
-}).then(function (y) {
-  window.y2 = y
-  y.share.textarea.bind(document.getElementById('textarea2'))
+function bindYjsInstance (y, suffix) {
+  y.define('textarea', Y.Text).bind(document.getElementById('textarea' + suffix))
  y.connector.socket.on('connection', function () {
-    document.getElementById('container2').removeAttribute('disconnected')
+    document.getElementById('container' + suffix).removeAttribute('disconnected')
  })
  y.connector.socket.on('disconnect', function () {
-    document.getElementById('container2').setAttribute('disconnected', true)
+    document.getElementById('container' + suffix).setAttribute('disconnected', true)
  })
-})
+}

-Y({
-  db: {
-    name: 'memory'
-  },
+let y1 = new Y('infinite-example', {
  connector: {
    name: 'websockets-client',
-    room: 'Textarea-example',
-    url: 'https://yjs-v13-third.herokuapp.com/'
-  },
-  share: {
-    textarea: 'Text'
+    url: 'http://127.0.0.1:1234'
  }
-}).then(function (y) {
-  window.y3 = y
-  y.share.textarea.bind(document.getElementById('textarea3'))
-  y.connector.socket.on('connection', function () {
-    document.getElementById('container3').removeAttribute('disconnected')
-  })
-  y.connector.socket.on('disconnect', function () {
-    document.getElementById('container3').setAttribute('disconnected', true)
-  })
 })
+window.y1 = y1
+bindYjsInstance(y1, '1')
+
+let y2 = new Y('infinite-example', {
+  connector: {
+    name: 'websockets-client',
+    url: 'http://127.0.0.1:1234'
+  }
+})
+window.y2 = y2
+bindYjsInstance(y2, '2')
+
+let y3 = new Y('infinite-example', {
+  connector: {
+    name: 'websockets-client',
+    url: 'http://127.0.0.1:1234'
+  }
+})
+window.y3 = y3
+bindYjsInstance(y1, '3')
--- a/examples/jigsaw/index.html
+++ b/examples/jigsaw/index.html
@@ -17,9 +17,7 @@
 		</g>
  </svg>
  <script src="../../y.js"></script>
-  <script src="../../../y-map/dist/y-map.js"></script>
-  <script src="../../../y-memory/y-memory.js"></script>
-  <script src="../../../y-websockets-client/y-websockets-client.js"></script>
+  <script src='../../../y-websockets-client/y-websockets-client.js'></script>
  <script src="../bower_components/d3/d3.js"></script>
  <script src="./index.js"></script>
 </body>
--- a/examples/jigsaw/index.js
+++ b/examples/jigsaw/index.js
@@ -1,74 +1,67 @@
-/* @flow */
 /* global Y, d3 */

-// initialize a shared object. This function call returns a promise!
-Y({
-  db: {
-    name: 'memory'
-  },
+let y = new Y('jigsaw-example', {
  connector: {
    name: 'websockets-client',
-    room: 'Puzzle-example',
-    url: 'http://localhost:1234'
-  },
-  share: {
-    piece1: 'Map',
-    piece2: 'Map',
-    piece3: 'Map',
-    piece4: 'Map'
+    url: 'http://127.0.0.1:1234'
  }
-}).then(function (y) {
-  window.yJigsaw = y
-  var origin // mouse start position - translation of piece
-  var drag = d3.behavior.drag()
-    .on('dragstart', function (params) {
-      // get the translation of the element
-      var translation = d3
-        .select(this)
-        .attr('transform')
-        .slice(10, -1)
-        .split(',')
-        .map(Number)
-      // mouse coordinates
-      var mouse = d3.mouse(this.parentNode)
-      origin = {
-        x: mouse[0] - translation[0],
-        y: mouse[1] - translation[1]
-      }
-    })
-    .on('drag', function () {
-      var mouse = d3.mouse(this.parentNode)
-      var x = mouse[0] - origin.x // =^= mouse - mouse at dragstart + translation at dragstart
-      var y = mouse[1] - origin.y
-      d3.select(this).attr('transform', 'translate(' + x + ',' + y + ')')
-    })
-    .on('dragend', function (piece, i) {
-      // save the current translation of the puzzle piece
-      var mouse = d3.mouse(this.parentNode)
-      var x = mouse[0] - origin.x
-      var y = mouse[1] - origin.y
-      piece.set('translation', {x: x, y: y})
-    })
+})

-  var data = [y.share.piece1, y.share.piece2, y.share.piece3, y.share.piece4]
-  var pieces = d3.select(document.querySelector('#puzzle-example')).selectAll('path').data(data)
+let jigsaw = y.define('jigsaw', Y.Map)
+window.yJigsaw = y

-  pieces
-    .classed('draggable', true)
-    .attr('transform', function (piece) {
-      var translation = piece.get('translation') || {x: 0, y: 0}
-      return 'translate(' + translation.x + ',' + translation.y + ')'
-    }).call(drag)
+var origin // mouse start position - translation of piece
+var drag = d3.behavior.drag()
+  .on('dragstart', function (params) {
+    // get the translation of the element
+    var translation = d3
+      .select(this)
+      .attr('transform')
+      .slice(10, -1)
+      .split(',')
+      .map(Number)
+    // mouse coordinates
+    var mouse = d3.mouse(this.parentNode)
+    origin = {
+      x: mouse[0] - translation[0],
+      y: mouse[1] - translation[1]
+    }
+  })
+  .on('drag', function () {
+    var mouse = d3.mouse(this.parentNode)
+    var x = mouse[0] - origin.x // =^= mouse - mouse at dragstart + translation at dragstart
+    var y = mouse[1] - origin.y
+    d3.select(this).attr('transform', 'translate(' + x + ',' + y + ')')
+  })
+  .on('dragend', function (piece, i) {
+    // save the current translation of the puzzle piece
+    var mouse = d3.mouse(this.parentNode)
+    var x = mouse[0] - origin.x
+    var y = mouse[1] - origin.y
+    jigsaw.set(piece, {x: x, y: y})
+  })

-  data.forEach(function (piece) {
-    piece.observe(function () {
-      // whenever a property of a piece changes, update the translation of the pieces
-      pieces
-        .transition()
-        .attr('transform', function (piece) {
-          var translation = piece.get('translation') || {x: 0, y: 0}
-          return 'translate(' + translation.x + ',' + translation.y + ')'
-        })
-    })
+var data = ['piece1', 'piece2', 'piece3', 'piece4']
+var pieces = d3.select(document.querySelector('#puzzle-example')).selectAll('path').data(data)
+
+pieces
+  .classed('draggable', true)
+  .attr('transform', function (piece) {
+    var translation = piece.get('translation') || {x: 0, y: 0}
+    return 'translate(' + translation.x + ',' + translation.y + ')'
+  }).call(drag)
+
+data.forEach(function (piece) {
+  jigsaw.observe(function () {
+    // whenever a property of a piece changes, update the translation of the pieces
+    pieces
+      .transition()
+      .attr('transform', function (piece) {
+        var translation = piece.get(piece)
+        if (translation == null || typeof translation.x !== 'number' || typeof translation.y !== 'number') {
+          translation = { x: 0, y: 0 }
+        }
+        return 'translate(' + translation.x + ',' + translation.y + ')'
+      })
  })
 })
--- a/examples/monaco/index.html
+++ b/examples/monaco/index.html
@@ -13,8 +13,8 @@
        width: 100%;
      }
    </style>
-    <script src="../bower_components/yjs/y.js"></script>
-    <script src="../bower_components/y-websockets-client/y-websockets-client.js"></script>
+    <script src="../../y.js"></script>
+    <script src='../../../y-websockets-client/y-websockets-client.js'></script>
    <script src="../node_modules/monaco-editor/min/vs/loader.js"></script>
    <script src="./index.js"></script>
  </body>
--- a/examples/monaco/index.js
+++ b/examples/monaco/index.js
@@ -2,29 +2,21 @@

 require.config({ paths: { 'vs': '../node_modules/monaco-editor/min/vs' } })

-require(['vs/editor/editor.main'], function () {
-  // Initialize a shared object. This function call returns a promise!
-  Y({
-    db: {
-      name: 'memory'
-    },
-    connector: {
-      name: 'websockets-client',
-      room: 'monaco-example'
-    },
-    sourceDir: '/bower_components',
-    share: {
-      monaco: 'Text' // y.share.monaco is of type Y.Text
-    }
-  }).then(function (y) {
-    window.yMonaco = y
-
-    // Create Monaco editor
-    var editor = monaco.editor.create(document.getElementById('monacoContainer'), {
-      language: 'javascript'
-    })
-
-    // Bind to y.share.monaco
-    y.share.monaco.bindMonaco(editor)
-  })
+let y = new Y('monaco-example', {
+  connector: {
+    name: 'websockets-client',
+    url: 'http://127.0.0.1:1234'
+  }
+})
+
+require(['vs/editor/editor.main'], function () {
+  window.yMonaco = y
+
+  // Create Monaco editor
+  var editor = monaco.editor.create(document.getElementById('monacoContainer'), {
+    language: 'javascript'
+  })
+
+  // Bind to y.share.monaco
+  y.define('monaco', Y.Text).bindMonaco(editor)
 })
--- a/examples/notes/index.html
+++ b/examples/notes/index.html
@@ -0,0 +1,8 @@
+<!DOCTYPE html>
+<html>
+</head>
+  <script src="./index.mjs" type="module"></script>
+</head>
+<body contenteditable="true">
+</body>
+</html>
--- a/examples/notes/index.mjs
+++ b/examples/notes/index.mjs
@@ -0,0 +1,48 @@
+
+import IndexedDBPersistence from '../../src/Persistences/IndexeddbPersistence.mjs'
+import YWebsocketsConnector from '../../src/Connectors/WebsocketsConnector/WebsocketsConnector.mjs'
+import Y from '../../src/Y.mjs'
+import YXmlFragment from '../../src/Types/YXml/YXmlFragment.mjs'
+
+const yCollection = new YCollection(new YWebsocketsConnector(), new IndexedDBPersistence())
+
+const y = yCollection.getDocument('my-notes')
+
+
+
+
+
+persistence.addConnector(persistence)
+
+const y = new Y()
+await persistence.persistY(y)
+
+
+connector.connectY('html-editor', y)
+persistence.connectY('html-editor', y)
+
+
+
+
+window.connector = connector
+
+window.onload = function () {
+  window.domBinding = new DomBinding(window.yXmlType, document.body, { scrollingElement: document.scrollingElement })
+}
+
+window.y = y
+window.yXmlType = y.define('xml', YXmlFragment)
+window.undoManager = new UndoManager(window.yXmlType, {
+  captureTimeout: 500
+})
+
+document.onkeydown = function interceptUndoRedo (e) {
+  if (e.keyCode === 90 && (e.metaKey || e.ctrlKey)) {
+    if (!e.shiftKey) {
+      window.undoManager.undo()
+    } else {
+      window.undoManager.redo()
+    }
+    e.preventDefault()
+  }
+}
--- a/examples/package-lock.json
+++ b/examples/package-lock.json
--- a/examples/package.json
+++ b/examples/package.json
@@ -9,12 +9,15 @@
  "author": "Kevin Jahns",
  "license": "MIT",
  "dependencies": {
-    "monaco-editor": "^0.8.3"
+    "monaco-editor": "^0.8.3",
+    "rollup": "^0.52.3"
  },
  "devDependencies": {
    "standard": "^10.0.2"
  },
  "standard": {
-    "ignore": ["bower_components"]
+    "ignore": [
+      "bower_components"
+    ]
  }
 }
--- a/examples/quill-cursors/index.html
+++ b/examples/quill-cursors/index.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <!-- Main quill library -->
+  <script src="../../node_modules/quill/dist/quill.min.js"></script>
+  <link href="../../node_modules/quill/dist/quill.snow.css" rel="stylesheet">
+  <!-- Quill cursors module -->
+  <script src="../../node_modules/quill-cursors/dist/quill-cursors.min.js"></script>
+  <link href="../../node_modules/quill-cursors/dist/quill-cursors.css" rel="stylesheet">
+  <!-- Yjs Library and connector -->
+  <script src="../../y.js"></script>
+  <script src='../../../y-websockets-client/y-websockets-client.js'></script>
+</head>
+<body>
+  <div id="quill-container">
+    <div id="quill">
+    </div>
+  </div>
+  <script src="./index.js"></script>
+</body>
+</html>
--- a/examples/quill-cursors/index.js
+++ b/examples/quill-cursors/index.js
@@ -0,0 +1,78 @@
+/* global Y, Quill, QuillCursors */
+
+Quill.register('modules/cursors', QuillCursors)
+
+let y = new Y('quill-0', {
+  connector: {
+    name: 'websockets-client',
+    url: 'http://127.0.0.1:1234'
+  }
+})
+let users = y.define('users', Y.Array)
+let myUserInfo = new Y.Map()
+myUserInfo.set('name', 'dada')
+myUserInfo.set('color', 'red')
+users.push([myUserInfo])
+
+let quill = new Quill('#quill-container', {
+  modules: {
+    toolbar: [
+      [{ header: [1, 2, false] }],
+      ['bold', 'italic', 'underline'],
+      ['image', 'code-block'],
+      [{ color: [] }, { background: [] }],    // Snow theme fills in values
+      [{ script: 'sub' }, { script: 'super' }],
+      ['link', 'image'],
+      ['link', 'code-block'],
+      [{ list: 'ordered' }, { list: 'bullet' }]
+    ],
+    cursors: {
+      hideDelay: 500
+    }
+  },
+  placeholder: 'Compose an epic...',
+  theme: 'snow'  // or 'bubble'
+})
+
+let cursors = quill.getModule('cursors')
+
+function drawCursors () {
+  cursors.clearCursors()
+  users.map((user, userId) => {
+    if (user !== myUserInfo) {
+      let relativeRange = user.get('range')
+      let lastUpdated = new Date(user.get('last updated'))
+      if (lastUpdated != null && new Date() - lastUpdated < 20000 && relativeRange != null) {
+        let start = Y.utils.fromRelativePosition(y, relativeRange.start).offset
+        let end = Y.utils.fromRelativePosition(y, relativeRange.end).offset
+        let range = { index: start, length: end - start }
+        cursors.setCursor(userId + '', range, user.get('name'), user.get('color'))
+      }
+    }
+  })
+}
+
+users.observeDeep(drawCursors)
+drawCursors()
+
+quill.on('selection-change', function (range) {
+  if (range != null) {
+    myUserInfo.set('range', {
+      start: Y.utils.getRelativePosition(yText, range.index),
+      end: Y.utils.getRelativePosition(yText, range.index + range.length)
+    })
+  } else {
+    myUserInfo.delete('range')
+  }
+  myUserInfo.set('last updated', new Date().toString())
+})
+
+let yText = y.define('quill', Y.Text)
+let quillBinding = new Y.QuillBinding(yText, quill)
+
+window.quillBinding = quillBinding
+window.yText = yText
+window.y = y
+window.quill = quill
+window.users = users
+window.cursors = cursors
--- a/examples/quill/index.html
+++ b/examples/quill/index.html
@@ -1,35 +1,18 @@
 <!DOCTYPE html>
 <html>
 <head>
-  <!-- quill does not include dist files! We are using the hosted version instead -->
-  <!--link rel="stylesheet" href="../bower_components/quill/dist/quill.snow.css" /-->
-  <link href="https://cdn.quilljs.com/1.0.4/quill.snow.css" rel="stylesheet">
-  <link href="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.5.1/katex.min.css" rel="stylesheet">
-  <link href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.2.0/styles/monokai-sublime.min.css" rel="stylesheet">
-  <style>
-    #quill-container {
-      border: 1px solid gray;
-      box-shadow: 0px 0px 10px gray;
-    }
-  </style>
+  <!-- Main Quill library -->
+  <script src="../../node_modules/quill/dist/quill.min.js"></script>
+  <link href="../../node_modules/quill/dist/quill.snow.css" rel="stylesheet">
+  <!-- Yjs Library and connector -->
+  <script src="../../y.js"></script>
+  <script src='../../../y-websockets-client/y-websockets-client.js'></script>
 </head>
 <body>
  <div id="quill-container">
    <div id="quill">
    </div>
  </div>
-
-  <script src="https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.5.1/katex.min.js" type="text/javascript"></script>
-  <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.2.0/highlight.min.js" type="text/javascript"></script>
-  <script src="https://cdn.quilljs.com/1.0.4/quill.js"></script>
-  <!-- quill does not include dist files! We are using the hosted version instead (see above)
-  <script src="../bower_components/quill/dist/quill.js"></script>
-  -->
-  <script src="../../y.js"></script>
-  <script src="../../../y-array/y-array.js"></script>
-  <script src="../../../y-richtext/dist/y-richtext.js"></script>
-  <script src="../../../y-memory/y-memory.js"></script>
-  <script src="../../../y-websockets-client/y-websockets-client.js"></script>
  <script src="./index.js"></script>
 </body>
 </html>
--- a/examples/quill/index.js
+++ b/examples/quill/index.js
@@ -1,40 +1,33 @@
 /* global Y, Quill */

-// initialize a shared object. This function call returns a promise!
-
-Y({
-  db: {
-    name: 'memory'
-  },
+let y = new Y('quill-cursors-0', {
  connector: {
    name: 'websockets-client',
-    room: 'richtext-example-quill-1.0-test',
-    url: 'http://localhost:1234'
-  },
-  sourceDir: '/bower_components',
-  share: {
-    richtext: 'Richtext' // y.share.richtext is of type Y.Richtext
+    url: 'http://127.0.0.1:1234'
  }
-}).then(function (y) {
-  window.yQuill = y
-
-  // create quill element
-  window.quill = new Quill('#quill', {
-    modules: {
-      formula: true,
-      syntax: true,
-      toolbar: [
-        [{ size: ['small', false, 'large', 'huge'] }],
-        ['bold', 'italic', 'underline'],
-        [{ color: [] }, { background: [] }],    // Snow theme fills in values
-        [{ script: 'sub' }, { script: 'super' }],
-        ['link', 'image'],
-        ['link', 'code-block'],
-        [{ list: 'ordered' }]
-      ]
-    },
-    theme: 'snow'
-  })
-  // bind quill to richtext type
-  y.share.richtext.bind(window.quill)
 })
+
+let quill = new Quill('#quill-container', {
+  modules: {
+    toolbar: [
+      [{ header: [1, 2, false] }],
+      ['bold', 'italic', 'underline'],
+      ['image', 'code-block'],
+      [{ color: [] }, { background: [] }],    // Snow theme fills in values
+      [{ script: 'sub' }, { script: 'super' }],
+      ['link', 'image'],
+      ['link', 'code-block'],
+      [{ list: 'ordered' }, { list: 'bullet' }]
+    ]
+  },
+  placeholder: 'Compose an epic...',
+  theme: 'snow'  // or 'bubble'
+})
+
+let yText = y.define('quill', Y.Text)
+
+let quillBinding = new Y.QuillBinding(yText, quill)
+window.quillBinding = quillBinding
+window.yText = yText
+window.y = y
+window.quill = quill
--- a/examples/rollup.config.js
+++ b/examples/rollup.config.js
@@ -4,10 +4,12 @@ import commonjs from 'rollup-plugin-commonjs'
 var pkg = require('./package.json')

 export default {
-  entry: 'yjs-dist.esm',
-  dest: 'yjs-dist.js',
-  moduleName: 'Y',
-  format: 'umd',
+  input: 'yjs-dist.mjs',
+  name: 'Y',
+  output: {
+    file: 'yjs-dist.js',
+    format: 'umd'
+  },
  plugins: [
    nodeResolve({
      main: true,
@@ -16,7 +18,7 @@ export default {
    }),
    commonjs()
  ],
-  sourceMap: true,
+  sourcemap: true,
  banner: `
 /**
 * ${pkg.name} - ${pkg.description}
--- a/examples/textarea/index.html
+++ b/examples/textarea/index.html
@@ -1,11 +1,9 @@
 <!DOCTYPE html>
 <html>
 <body>
-  <textarea style="width:80%;" rows=40 id="textfield" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false"></textarea>
+  <textarea style="width:80%;" rows=40 autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false"></textarea>
  <script src="../../y.js"></script>
-  <script src="../../../y-array/y-array.js"></script>
-  <script src="../../../y-text/y-text.js"></script>
-  <script src="../../../y-websockets-client/y-websockets-client.js"></script>
+  <script src='../../../y-websockets-client/y-websockets-client.js'></script>
  <script src="./index.js"></script>
 </body>
 </html>
--- a/examples/textarea/index.js
+++ b/examples/textarea/index.js
@@ -1,23 +1,15 @@
 /* global Y */

-// initialize a shared object. This function call returns a promise!
-Y({
-  db: {
-    name: 'memory'
-  },
+let y = new Y('textarea-example', {
  connector: {
    name: 'websockets-client',
-    room: 'Textarea-example2',
-    // url: '//localhost:1234',
-    url: 'https://yjs-v13.herokuapp.com/'
-  },
-  share: {
-    textarea: 'Text'
-  },
-  timeout: 5000 // reject if no connection was established within 5 seconds
-}).then(function (y) {
-  window.yTextarea = y
-
-  // bind the textarea to a shared text element
-  y.share.textarea.bind(document.getElementById('textfield'))
+    url: 'http://127.0.0.1:1234'
+  }
 })
+
+window.yTextarea = y
+
+// bind the textarea to a shared text element
+let type = y.define('textarea', Y.Text)
+let textarea = document.querySelector('textarea')
+window.binding = new Y.TextareaBinding(type, textarea)
--- a/examples/xml/index.html
+++ b/examples/xml/index.html
@@ -1,9 +1,10 @@
 <!DOCTYPE html>
 <html>
 </head>
-  <!-- jquery is not required for y-xml. It is just here for convenience, and to test batch operations. -->
+  <!-- jquery is not required for YXml. It is just here for convenience, and to test batch operations. -->
  <script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
-  <script src="../yjs-dist.js"></script>
+  <script src="../../y.js"></script>
+  <script src='../../../y-websockets-client/y-websockets-client.js'></script>
  <script src="./index.js"></script>
 </head>
 <body>
@@ -23,14 +24,16 @@
  </div>

  <script>
-    var commands = document.querySelectorAll(".command");
-    Array.prototype.forEach.call(document.querySelectorAll('.command'), function (command) {
-      var execute = function(){
-        eval(command.querySelector("input").value);
+    /* global $ */
+    var commands = document.querySelectorAll('.command')
+    Array.prototype.forEach.call(commands, function (command) {
+      var execute = function () {
+        // eslint-disable-next-line no-eval
+        eval(command.querySelector('input').value)
      }
-      command.querySelector("button").onclick = execute
-      $(command.querySelector("input")).keyup(function (e) {
-        if (e.keyCode == 13) {
+      command.querySelector('button').onclick = execute
+      $(command.querySelector('input')).keyup(function (e) {
+        if (e.keyCode === 13) {
          execute()
        }
      })
--- a/examples/xml/index.js
+++ b/examples/xml/index.js
@@ -1,23 +1,13 @@
 /* global Y */

-// initialize a shared object. This function call returns a promise!
-Y({
-  db: {
-    name: 'memory'
-  },
+let y = new Y('xml-example', {
  connector: {
    name: 'websockets-client',
-    // url: 'http://127.0.0.1:1234',
-    url: 'http://192.168.178.81:1234',
-    room: 'Xml-example'
-  },
-  sourceDir: '/bower_components',
-  share: {
-    xml: 'Xml("p")' // y.share.xml is of type Y.Xml with tagname "p"
+    url: 'http://127.0.0.1:1234'
  }
-}).then(function (y) {
-  window.yXml = y
-  // bind xml type to a dom, and put it in body
-  window.sharedDom = y.share.xml.getDom()
-  document.body.appendChild(window.sharedDom)
 })
+
+window.yXml = y
+// bind xml type to a dom, and put it in body
+window.sharedDom = y.define('xml', Y.XmlElement).toDom()
+document.body.appendChild(window.sharedDom)
--- a/examples/yjs-dist.esm
+++ b/examples/yjs-dist.esm
@@ -1,7 +0,0 @@
-
-import Y from '../src/Y.js'
-import yWebsocketsClient from '../../y-websockets-client/src/y-websockets-client.js'
-
-Y.extend(yWebsocketsClient)
-
-export default Y
--- a/package-lock.json
+++ b/package-lock.json
--- a/package.json
+++ b/package.json
@@ -1,22 +1,33 @@
 {
  "name": "yjs",
-  "version": "13.0.0-34",
+  "version": "13.0.0-60",
  "description": "A framework for real-time p2p shared editing on any data",
  "main": "./y.node.js",
  "browser": "./y.js",
  "module": "./src/y.js",
  "scripts": {
+    "start": "node --experimental-modules src/Connectors/WebsocketsConnector/server.mjs",
    "test": "npm run lint",
    "debug": "concurrently 'rollup -wc rollup.test.js' 'cutest-serve y.test.js -o'",
-    "lint": "standard",
+    "lint": "standard src/**/*.mjs test/**/*.mjs tests-lib/**/*.mjs",
+    "docs": "esdoc",
+    "serve-docs": "npm run docs && serve ./docs/",
    "dist": "rollup -c rollup.browser.js; rollup -c rollup.node.js",
    "watch": "concurrently 'rollup -wc rollup.browser.js' 'rollup -wc rollup.node.js'",
    "postversion": "npm run dist",
-    "postpublish": "tag-dist-files --overwrite-existing-tag"
+    "postpublish": "tag-dist-files --overwrite-existing-tag",
+    "demos": "concurrently 'node --experimental-modules src/Connectors/WebsocketsConnector/server.mjs' 'http-server'"
+  },
+  "now": {
+    "engines": {
+      "node": "10.x.x"
+    }
  },
  "files": [
    "y.*",
-    "src/*"
+    "src/*",
+    ".esdoc.json",
+    "docs/*"
  ],
  "standard": {
    "ignore": [
@@ -51,8 +62,14 @@
    "babel-plugin-transform-runtime": "^6.23.0",
    "babel-preset-latest": "^6.24.1",
    "chance": "^1.0.9",
+    "codemirror": "^5.37.0",
    "concurrently": "^3.4.0",
    "cutest": "^0.1.9",
+    "esdoc": "^1.0.4",
+    "esdoc-standard-plugin": "^1.0.0",
+    "quill": "^1.3.5",
+    "quill-cursors": "^1.0.2",
+    "rollup": "^0.58.2",
    "rollup-plugin-babel": "^2.7.1",
    "rollup-plugin-commonjs": "^8.0.2",
    "rollup-plugin-inject": "^2.0.0",
@@ -61,13 +78,10 @@
    "rollup-plugin-uglify": "^1.0.2",
    "rollup-regenerator-runtime": "^6.23.1",
    "rollup-watch": "^3.2.2",
-    "standard": "^10.0.2",
+    "standard": "^11.0.1",
    "tag-dist-files": "^0.1.6"
  },
  "dependencies": {
-    "debug": "^2.6.8",
-    "fast-diff": "^1.1.2",
-    "utf-8": "^1.0.0",
-    "utf8": "^2.1.2"
+    "uws": "^10.148.0"
  }
 }
--- a/rollup.browser.js
+++ b/rollup.browser.js
@@ -5,7 +5,7 @@ import commonjs from 'rollup-plugin-commonjs'
 var pkg = require('./package.json')

 export default {
-  input: 'src/Y.js',
+  input: 'src/Y.dist.mjs',
  name: 'Y',
  sourcemap: true,
  output: {
@@ -22,7 +22,7 @@ export default {
    babel(),
    uglify({
      mangle: {
-        except: ['YMap', 'Y', 'YArray', 'YText', 'YXmlFragment', 'YXmlElement', 'YXmlEvent', 'YXmlText', 'YEvent', 'YArrayEvent', 'YMapEvent', 'Type', 'Delete', 'ItemJSON', 'ItemString', 'Item']
+        except: ['YMap', 'Y', 'YArray', 'YText', 'YXmlHook', 'YXmlFragment', 'YXmlElement', 'YXmlEvent', 'YXmlText', 'YEvent', 'YArrayEvent', 'YMapEvent', 'Type', 'Delete', 'ItemJSON', 'ItemString', 'Item']
      },
      output: {
        comments: function (node, comment) {
--- a/rollup.node.js
+++ b/rollup.node.js
@@ -3,7 +3,7 @@ import commonjs from 'rollup-plugin-commonjs'
 var pkg = require('./package.json')

 export default {
-  input: 'src/y-dist.cjs.js',
+  input: 'src/Y.dist.mjs',
  nameame: 'Y',
  sourcemap: true,
  output: {
--- a/rollup.test.js
+++ b/rollup.test.js
@@ -3,7 +3,7 @@ import commonjs from 'rollup-plugin-commonjs'
 import multiEntry from 'rollup-plugin-multi-entry'

 export default {
-  input: 'test/y-xml.tests.js',
+  input: 'test/index.mjs',
  name: 'y-tests',
  sourcemap: true,
  output: {
@@ -11,12 +11,12 @@ export default {
    format: 'umd'
  },
  plugins: [
+    multiEntry(),
    nodeResolve({
      main: true,
      module: true,
      browser: true
    }),
-    commonjs(),
-    multiEntry()
+    commonjs()
  ]
 }
--- a/src/Binary/Decoder.js
+++ b/src/Binary/Decoder.js
@@ -1,120 +0,0 @@
-import utf8 from 'utf-8'
-import ID from '../Util/ID.js'
-import { default as RootID, RootFakeUserID } from '../Util/RootID.js'
-
-export default class BinaryDecoder {
-  constructor (buffer) {
-    if (buffer instanceof ArrayBuffer) {
-      this.uint8arr = new Uint8Array(buffer)
-    } else if (buffer instanceof Uint8Array || (typeof Buffer !== 'undefined' && buffer instanceof Buffer)) {
-      this.uint8arr = buffer
-    } else {
-      throw new Error('Expected an ArrayBuffer or Uint8Array!')
-    }
-    this.pos = 0
-  }
-  /**
-   * Clone this decoder instance
-   * Optionally set a new position parameter
-   */
-  clone (newPos = this.pos) {
-    let decoder = new BinaryDecoder(this.uint8arr)
-    decoder.pos = newPos
-    return decoder
-  }
-  /**
-   * Number of bytes
-   */
-  get length () {
-    return this.uint8arr.length
-  }
-  /**
-   * Skip one byte, jump to the next position
-   */
-  skip8 () {
-    this.pos++
-  }
-  /**
-   * Read one byte as unsigned integer
-   */
-  readUint8 () {
-    return this.uint8arr[this.pos++]
-  }
-  /**
-   * Read 4 bytes as unsigned integer
-   */
-  readUint32 () {
-    let uint =
-      this.uint8arr[this.pos] +
-      (this.uint8arr[this.pos + 1] << 8) +
-      (this.uint8arr[this.pos + 2] << 16) +
-      (this.uint8arr[this.pos + 3] << 24)
-    this.pos += 4
-    return uint
-  }
-  /**
-   * Look ahead without incrementing position
-   * to the next byte and read it as unsigned integer
-   */
-  peekUint8 () {
-    return this.uint8arr[this.pos]
-  }
-  /**
-   * Read unsigned integer (32bit) with variable length
-   * 1/8th of the storage is used as encoding overhead
-   *  - numbers < 2^7 is stored in one byte
-   *  - numbers < 2^14 is stored in two bytes
-   *  ..
-   */
-  readVarUint () {
-    let num = 0
-    let len = 0
-    while (true) {
-      let r = this.uint8arr[this.pos++]
-      num = num | ((r & 0b1111111) << len)
-      len += 7
-      if (r < 1 << 7) {
-        return num >>> 0 // return unsigned number!
-      }
-      if (len > 35) {
-        throw new Error('Integer out of range!')
-      }
-    }
-  }
-  /**
-   * Read string of variable length
-   * - varUint is used to store the length of the string
-   */
-  readVarString () {
-    let len = this.readVarUint()
-    let bytes = new Array(len)
-    for (let i = 0; i < len; i++) {
-      bytes[i] = this.uint8arr[this.pos++]
-    }
-    return utf8.getStringFromBytes(bytes)
-  }
-  /**
-   *  Look ahead and read varString without incrementing position
-   */
-  peekVarString () {
-    let pos = this.pos
-    let s = this.readVarString()
-    this.pos = pos
-    return s
-  }
-  /**
-   * Read ID
-   * - If first varUint read is 0xFFFFFF a RootID is returned
-   * - Otherwise an ID is returned
-   */
-  readID () {
-    let user = this.readVarUint()
-    if (user === RootFakeUserID) {
-      // read property name and type id
-      const rid = new RootID(this.readVarString(), null)
-      rid.type = this.readVarUint()
-      return rid
-    }
-    return new ID(user, this.readVarUint())
-  }
-}
--- a/src/Binary/Encoder.js
+++ b/src/Binary/Encoder.js
@@ -1,83 +0,0 @@
-import utf8 from 'utf-8'
-import { RootFakeUserID } from '../Util/RootID.js'
-
-const bits7 = 0b1111111
-const bits8 = 0b11111111
-
-export default class BinaryEncoder {
-  constructor () {
-    // TODO: implement chained Uint8Array buffers instead of Array buffer
-    this.data = []
-  }
-
-  get length () {
-    return this.data.length
-  }
-
-  get pos () {
-    return this.data.length
-  }
-
-  createBuffer () {
-    return Uint8Array.from(this.data).buffer
-  }
-
-  writeUint8 (num) {
-    this.data.push(num & bits8)
-  }
-
-  setUint8 (pos, num) {
-    this.data[pos] = num & bits8
-  }
-
-  writeUint16 (num) {
-    this.data.push(num & bits8, (num >>> 8) & bits8)
-  }
-
-  setUint16 (pos, num) {
-    this.data[pos] = num & bits8
-    this.data[pos + 1] = (num >>> 8) & bits8
-  }
-
-  writeUint32 (num) {
-    for (let i = 0; i < 4; i++) {
-      this.data.push(num & bits8)
-      num >>>= 8
-    }
-  }
-
-  setUint32 (pos, num) {
-    for (let i = 0; i < 4; i++) {
-      this.data[pos + i] = num & bits8
-      num >>>= 8
-    }
-  }
-
-  writeVarUint (num) {
-    while (num >= 0b10000000) {
-      this.data.push(0b10000000 | (bits7 & num))
-      num >>>= 7
-    }
-    this.data.push(bits7 & num)
-  }
-
-  writeVarString (str) {
-    let bytes = utf8.setBytesFromString(str)
-    let len = bytes.length
-    this.writeVarUint(len)
-    for (let i = 0; i < len; i++) {
-      this.data.push(bytes[i])
-    }
-  }
-
-  writeID (id) {
-    const user = id.user
-    this.writeVarUint(user)
-    if (user !== RootFakeUserID) {
-      this.writeVarUint(id.clock)
-    } else {
-      this.writeVarString(id.name)
-      this.writeVarUint(id.type)
-    }
-  }
-}
--- a/src/Bindings/Binding.mjs
+++ b/src/Bindings/Binding.mjs
@@ -0,0 +1,47 @@
+
+import { createMutualExclude } from '../Util/mutualExclude.mjs'
+
+/**
+ * Abstract class for bindings.
+ *
+ * A binding handles data binding from a Yjs type to a data object. For example,
+ * you can bind a Quill editor instance to a YText instance with the `QuillBinding` class.
+ *
+ * It is expected that a concrete implementation accepts two parameters
+ * (type and binding target).
+ *
+ * @example
+ *   const quill = new Quill(document.createElement('div'))
+ *   const type = y.define('quill', Y.Text)
+ *   const binding = new Y.QuillBinding(quill, type)
+ *
+ */
+export default class Binding {
+  /**
+   * @param {YType} type Yjs type.
+   * @param {any} target Binding Target.
+   */
+  constructor (type, target) {
+    /**
+     * The Yjs type that is bound to `target`
+     * @type {YType}
+     */
+    this.type = type
+    /**
+     * The target that `type` is bound to.
+     * @type {*}
+     */
+    this.target = target
+    /**
+     * @private
+     */
+    this._mutualExclude = createMutualExclude()
+  }
+  /**
+   * Remove all data observers (both from the type and the target).
+   */
+  destroy () {
+    this.type = null
+    this.target = null
+  }
+}
--- a/src/Bindings/CodeMirrorBinding/CodeMirrorBinding.mjs
+++ b/src/Bindings/CodeMirrorBinding/CodeMirrorBinding.mjs
@@ -0,0 +1,56 @@
+
+import Binding from '../Binding.mjs'
+import simpleDiff from '../../Util/simpleDiff.mjs'
+import { getRelativePosition, fromRelativePosition } from '../../Util/relativePosition.mjs'
+
+function typeObserver () {
+  this._mutualExclude(() => {
+    const textarea = this.target
+    const textType = this.type
+    const relativeStart = getRelativePosition(textType, textarea.selectionStart)
+    const relativeEnd = getRelativePosition(textType, textarea.selectionEnd)
+    textarea.value = textType.toString()
+    const start = fromRelativePosition(textType._y, relativeStart)
+    const end = fromRelativePosition(textType._y, relativeEnd)
+    textarea.setSelectionRange(start, end)
+  })
+}
+
+function domObserver () {
+  this._mutualExclude(() => {
+    let diff = simpleDiff(this.type.toString(), this.target.value)
+    this.type.delete(diff.pos, diff.remove)
+    this.type.insert(diff.pos, diff.insert)
+  })
+}
+
+/**
+ * A binding that binds a YText to a dom textarea.
+ *
+ * This binding is automatically destroyed when its parent is deleted.
+ *
+ * @example
+ *   const textare = document.createElement('textarea')
+ *   const type = y.define('textarea', Y.Text)
+ *   const binding = new Y.QuillBinding(type, textarea)
+ *
+ */
+export default class TextareaBinding extends Binding {
+  constructor (textType, domTextarea) {
+    // Binding handles textType as this.type and domTextarea as this.target
+    super(textType, domTextarea)
+    // set initial value
+    domTextarea.value = textType.toString()
+    // Observers are handled by this class
+    this._typeObserver = typeObserver.bind(this)
+    this._domObserver = domObserver.bind(this)
+    textType.observe(this._typeObserver)
+    domTextarea.addEventListener('input', this._domObserver)
+  }
+  destroy () {
+    // Remove everything that is handled by this class
+    this.type.unobserve(this._typeObserver)
+    this.target.unobserve(this._domObserver)
+    super.destroy()
+  }
+}
--- a/src/Bindings/DomBinding/DomBinding.mjs
+++ b/src/Bindings/DomBinding/DomBinding.mjs
@@ -0,0 +1,140 @@
+/* global MutationObserver */
+
+import Binding from '../Binding.mjs'
+import { createAssociation, removeAssociation } from './util.mjs'
+import { beforeTransactionSelectionFixer, afterTransactionSelectionFixer } from './selection.mjs'
+import { defaultFilter, applyFilterOnType } from './filter.mjs'
+import typeObserver from './typeObserver.mjs'
+import domObserver from './domObserver.mjs'
+
+/**
+ * A binding that binds the children of a YXmlFragment to a DOM element.
+ *
+ * This binding is automatically destroyed when its parent is deleted.
+ *
+ * @example
+ * const div = document.createElement('div')
+ * const type = y.define('xml', Y.XmlFragment)
+ * const binding = new Y.QuillBinding(type, div)
+ *
+ */
+export default class DomBinding extends Binding {
+  /**
+   * @param {YXmlFragment} type The bind source. This is the ultimate source of
+   *                            truth.
+   * @param {Element} target The bind target. Mirrors the target.
+   * @param {Object} [opts] Optional configurations
+
+   * @param {FilterFunction} [opts.filter=defaultFilter] The filter function to use.
+   */
+  constructor (type, target, opts = {}) {
+    // Binding handles textType as this.type and domTextarea as this.target
+    super(type, target)
+    this.opts = opts
+    opts.document = opts.document || document
+    opts.hooks = opts.hooks || {}
+    this.scrollingElement = opts.scrollingElement || null
+    /**
+     * Maps each DOM element to the type that it is associated with.
+     * @type {Map}
+     */
+    this.domToType = new Map()
+    /**
+     * Maps each YXml type to the DOM element that it is associated with.
+     * @type {Map}
+     */
+    this.typeToDom = new Map()
+    /**
+     * Defines which DOM attributes and elements to filter out.
+     * Also filters remote changes.
+     * @type {FilterFunction}
+     */
+    this.filter = opts.filter || defaultFilter
+    // set initial value
+    target.innerHTML = ''
+    type.forEach(child => {
+      target.insertBefore(child.toDom(opts.document, opts.hooks, this), null)
+    })
+    this._typeObserver = typeObserver.bind(this)
+    this._domObserver = (mutations) => {
+      domObserver.call(this, mutations, opts.document)
+    }
+    type.observeDeep(this._typeObserver)
+    this._mutationObserver = new MutationObserver(this._domObserver)
+    this._mutationObserver.observe(target, {
+      childList: true,
+      attributes: true,
+      characterData: true,
+      subtree: true
+    })
+    const y = type._y
+    // Force flush dom changes before Type changes are applied (they might
+    // modify the dom)
+    this._beforeTransactionHandler = (y, transaction, remote) => {
+      this._domObserver(this._mutationObserver.takeRecords())
+      beforeTransactionSelectionFixer(y, this, transaction, remote)
+    }
+    y.on('beforeTransaction', this._beforeTransactionHandler)
+    this._afterTransactionHandler = (y, transaction, remote) => {
+      afterTransactionSelectionFixer(y, this, transaction, remote)
+      // remove associations
+      // TODO: this could be done more efficiently
+      // e.g. Always delete using the following approach, or removeAssociation
+      // in dom/type-observer..
+      transaction.deletedStructs.forEach(type => {
+        const dom = this.typeToDom.get(type)
+        if (dom !== undefined) {
+          removeAssociation(this, dom, type)
+        }
+      })
+    }
+    y.on('afterTransaction', this._afterTransactionHandler)
+    // Before calling observers, apply dom filter to all changed and new types.
+    this._beforeObserverCallsHandler = (y, transaction) => {
+      // Apply dom filter to new and changed types
+      transaction.changedTypes.forEach((subs, type) => {
+        // Only check attributes. New types are filtered below.
+        if ((subs.size > 1 || (subs.size === 1 && subs.has(null) === false))) {
+          applyFilterOnType(y, this, type)
+        }
+      })
+      transaction.newTypes.forEach(type => {
+        applyFilterOnType(y, this, type)
+      })
+    }
+    y.on('beforeObserverCalls', this._beforeObserverCallsHandler)
+    createAssociation(this, target, type)
+  }
+
+  /**
+   * NOTE: currently does not apply filter to existing elements!
+   * @param {FilterFunction} filter The filter function to use from now on.
+   */
+  setFilter (filter) {
+    this.filter = filter
+    // TODO: apply filter to all elements
+  }
+
+  /**
+   * Remove all properties that are handled by this class.
+   */
+  destroy () {
+    this.domToType = null
+    this.typeToDom = null
+    this.type.unobserveDeep(this._typeObserver)
+    this._mutationObserver.disconnect()
+    const y = this.type._y
+    y.off('beforeTransaction', this._beforeTransactionHandler)
+    y.off('beforeObserverCalls', this._beforeObserverCallsHandler)
+    y.off('afterTransaction', this._afterTransactionHandler)
+    super.destroy()
+  }
+}
+
+  /**
+   * A filter defines which elements and attributes to share.
+   * Return null if the node should be filtered. Otherwise return the Map of
+   * accepted attributes.
+   *
+   * @typedef {function(nodeName: String, attrs: Map): Map|null} FilterFunction
+   */
--- a/src/Bindings/DomBinding/domObserver.mjs
+++ b/src/Bindings/DomBinding/domObserver.mjs
@@ -0,0 +1,144 @@
+
+import YXmlHook from '../../Types/YXml/YXmlHook.mjs'
+import {
+  iterateUntilUndeleted,
+  removeAssociation,
+  insertNodeHelper } from './util.mjs'
+import diff from '../../Util/simpleDiff.mjs'
+import YXmlFragment from '../../Types/YXml/YXmlFragment.mjs'
+
+/**
+ * 1. Check if any of the nodes was deleted
+ * 2. Iterate over the children.
+ *    2.1 If a node exists that is not yet bound to a type, insert a new node
+ *    2.2 If _contents.length < dom.childNodes.length, fill the
+ *        rest of _content with childNodes
+ *    2.3 If a node was moved, delete it and
+ *       recreate a new yxml element that is bound to that node.
+ *       You can detect that a node was moved because expectedId
+ *       !== actualId in the list
+ * @private
+ */
+function applyChangesFromDom (binding, dom, yxml, _document) {
+  if (yxml == null || yxml === false || yxml.constructor === YXmlHook) {
+    return
+  }
+  const y = yxml._y
+  const knownChildren = new Set()
+  for (let i = dom.childNodes.length - 1; i >= 0; i--) {
+    const type = binding.domToType.get(dom.childNodes[i])
+    if (type !== undefined && type !== false) {
+      knownChildren.add(type)
+    }
+  }
+  // 1. Check if any of the nodes was deleted
+  yxml.forEach(function (childType) {
+    if (knownChildren.has(childType) === false) {
+      childType._delete(y)
+      removeAssociation(binding, binding.typeToDom.get(childType), childType)
+    }
+  })
+  // 2. iterate
+  const childNodes = dom.childNodes
+  const len = childNodes.length
+  let prevExpectedType = null
+  let expectedType = iterateUntilUndeleted(yxml._start)
+  for (let domCnt = 0; domCnt < len; domCnt++) {
+    const childNode = childNodes[domCnt]
+    const childType = binding.domToType.get(childNode)
+    if (childType !== undefined) {
+      if (childType === false) {
+        // should be ignored or is going to be deleted
+        continue
+      }
+      if (expectedType !== null) {
+        if (expectedType !== childType) {
+          // 2.3 Not expected node
+          if (childType._parent !== yxml) {
+            // child was moved from another parent
+            // childType is going to be deleted by its previous parent
+            removeAssociation(binding, childNode, childType)
+          } else {
+            // child was moved to a different position.
+            removeAssociation(binding, childNode, childType)
+            childType._delete(y)
+          }
+          prevExpectedType = insertNodeHelper(yxml, prevExpectedType, childNode, _document, binding)
+        } else {
+          // Found expected node. Continue.
+          prevExpectedType = expectedType
+          expectedType = iterateUntilUndeleted(expectedType._right)
+        }
+      } else {
+        // 2.2 Fill _content with child nodes
+        prevExpectedType = insertNodeHelper(yxml, prevExpectedType, childNode, _document, binding)
+      }
+    } else {
+      // 2.1 A new node was found
+      prevExpectedType = insertNodeHelper(yxml, prevExpectedType, childNode, _document, binding)
+    }
+  }
+}
+
+/**
+ * @private
+ */
+export default function domObserver (mutations, _document) {
+  this._mutualExclude(() => {
+    this.type._y.transact(() => {
+      let diffChildren = new Set()
+      mutations.forEach(mutation => {
+        const dom = mutation.target
+        const yxml = this.domToType.get(dom)
+        if (yxml === undefined) { // In case yxml is undefined, we double check if we forgot to bind the dom
+          let parent = dom
+          let yParent
+          do {
+            parent = parent.parentElement
+            yParent = this.domToType.get(parent)
+          } while (yParent === undefined && parent !== null)
+          if (yParent !== false && yParent !== undefined && yParent.constructor !== YXmlHook) {
+            diffChildren.add(parent)
+          }
+          return
+        } else if (yxml === false || yxml.constructor === YXmlHook) {
+          // dom element is filtered / a dom hook
+          return
+        }
+        switch (mutation.type) {
+          case 'characterData':
+            var change = diff(yxml.toString(), dom.nodeValue)
+            yxml.delete(change.pos, change.remove)
+            yxml.insert(change.pos, change.insert)
+            break
+          case 'attributes':
+            if (yxml.constructor === YXmlFragment) {
+              break
+            }
+            let name = mutation.attributeName
+            let val = dom.getAttribute(name)
+            // check if filter accepts attribute
+            let attributes = new Map()
+            attributes.set(name, val)
+            if (yxml.constructor !== YXmlFragment && this.filter(dom.nodeName, attributes).size > 0) {
+              if (yxml.getAttribute(name) !== val) {
+                if (val == null) {
+                  yxml.removeAttribute(name)
+                } else {
+                  yxml.setAttribute(name, val)
+                }
+              }
+            }
+            break
+          case 'childList':
+            diffChildren.add(mutation.target)
+            break
+        }
+      })
+      for (let dom of diffChildren) {
+        const yxml = this.domToType.get(dom)
+        applyChangesFromDom(this, dom, yxml, _document)
+      }
+    })
+  })
+}
--- a/src/Bindings/DomBinding/domToType.mjs
+++ b/src/Bindings/DomBinding/domToType.mjs
@@ -0,0 +1,61 @@
+
+import YXmlText from '../../Types/YXml/YXmlText.mjs'
+import YXmlHook from '../../Types/YXml/YXmlHook.mjs'
+import YXmlElement from '../../Types/YXml/YXmlElement.mjs'
+import { createAssociation, domsToTypes } from './util.mjs'
+import { filterDomAttributes, defaultFilter } from './filter.mjs'
+
+/**
+ * Creates a Yjs type (YXml) based on the contents of a DOM Element.
+ *
+ * @param {Element|TextNode} element The DOM Element
+ * @param {?Document} _document Optional. Provide the global document object
+ * @param {Hooks} [hooks = {}] Optional. Set of Yjs Hooks
+ * @param {Filter} [filter=defaultFilter] Optional. Dom element filter
+ * @param {?DomBinding} binding Warning: This property is for internal use only!
+ * @return {YXmlElement | YXmlText}
+ */
+export default function domToType (element, _document = document, hooks = {}, filter = defaultFilter, binding) {
+  let type
+  switch (element.nodeType) {
+    case _document.ELEMENT_NODE:
+      let hookName = null
+      let hook
+      // configure `hookName !== undefined` if element is a hook.
+      if (element.hasAttribute('data-yjs-hook')) {
+        hookName = element.getAttribute('data-yjs-hook')
+        hook = hooks[hookName]
+        if (hook === undefined) {
+          console.error(`Unknown hook "${hookName}". Deleting yjsHook dataset property.`)
+          delete element.removeAttribute('data-yjs-hook')
+          hookName = null
+        }
+      }
+      if (hookName === null) {
+        // Not a hook
+        const attrs = filterDomAttributes(element, filter)
+        if (attrs === null) {
+          type = false
+        } else {
+          type = new YXmlElement(element.nodeName)
+          attrs.forEach((val, key) => {
+            type.setAttribute(key, val)
+          })
+          type.insert(0, domsToTypes(element.childNodes, document, hooks, filter, binding))
+        }
+      } else {
+        // Is a hook
+        type = new YXmlHook(hookName)
+        hook.fillType(element, type)
+      }
+      break
+    case _document.TEXT_NODE:
+      type = new YXmlText()
+      type.insert(0, element.nodeValue)
+      break
+    default:
+      throw new Error('Can\'t transform this node type to a YXml type!')
+  }
+  createAssociation(binding, element, type)
+  return type
+}
--- a/src/Bindings/DomBinding/filter.mjs
+++ b/src/Bindings/DomBinding/filter.mjs
@@ -0,0 +1,60 @@
+import isParentOf from '../../Util/isParentOf.mjs'
+
+/**
+ * Default filter method (does nothing).
+ *
+ * @param {String} nodeName The nodeName of the element
+ * @param {Map} attrs Map of key-value pairs that are attributes of the node.
+ * @return {Map | null} The allowed attributes or null, if the element should be
+ *                      filtered.
+ */
+export function defaultFilter (nodeName, attrs) {
+  // TODO: implement basic filter that filters out dangerous properties!
+  return attrs
+}
+
+/**
+ *
+ */
+export function filterDomAttributes (dom, filter) {
+  const attrs = new Map()
+  for (let i = dom.attributes.length - 1; i >= 0; i--) {
+    const attr = dom.attributes[i]
+    attrs.set(attr.name, attr.value)
+  }
+  return filter(dom.nodeName, attrs)
+}
+
+/**
+ * Applies a filter on a type.
+ *
+ * @param {Y} y The Yjs instance.
+ * @param {DomBinding} binding The DOM binding instance that has the dom filter.
+ * @param {YXmlElement | YXmlFragment } type The type to apply the filter to.
+ *
+ * @private
+ */
+export function applyFilterOnType (y, binding, type) {
+  if (isParentOf(binding.type, type)) {
+    const nodeName = type.nodeName
+    let attributes = new Map()
+    if (type.getAttributes !== undefined) {
+      let attrs = type.getAttributes()
+      for (let key in attrs) {
+        attributes.set(key, attrs[key])
+      }
+    }
+    const filteredAttributes = binding.filter(nodeName, new Map(attributes))
+    if (filteredAttributes === null) {
+      type._delete(y)
+    } else {
+      // iterate original attributes
+      attributes.forEach((value, key) => {
+        // delete all attributes that are not in filteredAttributes
+        if (filteredAttributes.has(key) === false) {
+          type.removeAttribute(key)
+        }
+      })
+    }
+  }
+}
--- a/src/Bindings/DomBinding/selection.mjs
+++ b/src/Bindings/DomBinding/selection.mjs
@@ -1,36 +1,42 @@
 /* globals getSelection */

-import { getRelativePosition, fromRelativePosition } from '../../Util/relativePosition.js'
+import { getRelativePosition, fromRelativePosition } from '../../Util/relativePosition.mjs'

 let browserSelection = null
 let relativeSelection = null

+/**
+ * @private
+ */
 export let beforeTransactionSelectionFixer
 if (typeof getSelection !== 'undefined') {
-  beforeTransactionSelectionFixer = function _beforeTransactionSelectionFixer (y, transaction, remote) {
+  beforeTransactionSelectionFixer = function _beforeTransactionSelectionFixer (y, domBinding, transaction, remote) {
    if (!remote) {
      return
    }
    relativeSelection = { from: null, to: null, fromY: null, toY: null }
    browserSelection = getSelection()
    const anchorNode = browserSelection.anchorNode
-    if (anchorNode !== null && anchorNode._yxml != null) {
-      const yxml = anchorNode._yxml
-      relativeSelection.from = getRelativePosition(yxml, browserSelection.anchorOffset)
-      relativeSelection.fromY = yxml._y
+    const anchorNodeType = domBinding.domToType.get(anchorNode)
+    if (anchorNode !== null && anchorNodeType !== undefined) {
+      relativeSelection.from = getRelativePosition(anchorNodeType, browserSelection.anchorOffset)
+      relativeSelection.fromY = anchorNodeType._y
    }
    const focusNode = browserSelection.focusNode
-    if (focusNode !== null && focusNode._yxml != null) {
-      const yxml = focusNode._yxml
-      relativeSelection.to = getRelativePosition(yxml, browserSelection.focusOffset)
-      relativeSelection.toY = yxml._y
+    const focusNodeType = domBinding.domToType.get(focusNode)
+    if (focusNode !== null && focusNodeType !== undefined) {
+      relativeSelection.to = getRelativePosition(focusNodeType, browserSelection.focusOffset)
+      relativeSelection.toY = focusNodeType._y
    }
  }
 } else {
  beforeTransactionSelectionFixer = function _fakeBeforeTransactionSelectionFixer () {}
 }

-export function afterTransactionSelectionFixer (y, transaction, remote) {
+/**
+ * @private
+ */
+export function afterTransactionSelectionFixer (y, domBinding, transaction, remote) {
  if (relativeSelection === null || !remote) {
    return
  }
@@ -46,7 +52,7 @@ export function afterTransactionSelectionFixer (y, transaction, remote) {
  if (from !== null) {
    let sel = fromRelativePosition(fromY, from)
    if (sel !== null) {
-      let node = sel.type.getDom()
+      let node = domBinding.typeToDom.get(sel.type)
      let offset = sel.offset
      if (node !== anchorNode || offset !== anchorOffset) {
        anchorNode = node
@@ -58,7 +64,7 @@ export function afterTransactionSelectionFixer (y, transaction, remote) {
  if (to !== null) {
    let sel = fromRelativePosition(toY, to)
    if (sel !== null) {
-      let node = sel.type.getDom()
+      let node = domBinding.typeToDom.get(sel.type)
      let offset = sel.offset
      if (node !== focusNode || offset !== focusOffset) {
        focusNode = node
@@ -75,7 +81,4 @@ export function afterTransactionSelectionFixer (y, transaction, remote) {
      focusOffset
    )
  }
-  // delete, so the objects can be gc'd
-  relativeSelection = null
-  browserSelection = null
 }
--- a/src/Bindings/DomBinding/typeObserver.mjs
+++ b/src/Bindings/DomBinding/typeObserver.mjs
@@ -0,0 +1,99 @@
+/* global getSelection */
+
+import YXmlText from '../../Types/YXml/YXmlText.mjs'
+import YXmlHook from '../../Types/YXml/YXmlHook.mjs'
+import { removeDomChildrenUntilElementFound } from './util.mjs'
+
+function findScrollReference (scrollingElement) {
+  if (scrollingElement !== null) {
+    let anchor = getSelection().anchorNode
+    if (anchor == null) {
+      let children = scrollingElement.children // only iterate through non-text nodes
+      for (let i = 0; i < children.length; i++) {
+        const elem = children[i]
+        const rect = elem.getBoundingClientRect()
+        if (rect.top >= 0) {
+          return { elem, top: rect.top }
+        }
+      }
+    } else {
+      if (anchor.nodeType === document.TEXT_NODE) {
+        anchor = anchor.parentElement
+      }
+      const top = anchor.getBoundingClientRect().top
+      return { elem: anchor, top: top }
+    }
+  }
+  return null
+}
+
+function fixScroll (scrollingElement, ref) {
+  if (ref !== null) {
+    const { elem, top } = ref
+    const currentTop = elem.getBoundingClientRect().top
+    const newScroll = scrollingElement.scrollTop + currentTop - top
+    if (newScroll >= 0) {
+      scrollingElement.scrollTop = newScroll
+    }
+  }
+}
+
+/**
+ * @private
+ */
+export default function typeObserver (events) {
+  this._mutualExclude(() => {
+    const scrollRef = findScrollReference(this.scrollingElement)
+    events.forEach(event => {
+      const yxml = event.target
+      const dom = this.typeToDom.get(yxml)
+      if (dom !== undefined && dom !== false) {
+        if (yxml.constructor === YXmlText) {
+          dom.nodeValue = yxml.toString()
+        } else if (event.attributesChanged !== undefined) {
+          // update attributes
+          event.attributesChanged.forEach(attributeName => {
+            const value = yxml.getAttribute(attributeName)
+            if (value === undefined) {
+              dom.removeAttribute(attributeName)
+            } else {
+              dom.setAttribute(attributeName, value)
+            }
+          })
+          /*
+           * TODO: instead of hard-checking the types, it would be best to
+           *       specify the type's features. E.g.
+           *         - _yxmlHasAttributes
+           *         - _yxmlHasChildren
+           *       Furthermore, the features shouldn't be encoded in the types,
+           *       only in the attributes (above)
+           */
+          if (event.childListChanged && yxml.constructor !== YXmlHook) {
+            let currentChild = dom.firstChild
+            yxml.forEach(childType => {
+              const childNode = this.typeToDom.get(childType)
+              switch (childNode) {
+                case undefined:
+                  // Does not exist. Create it.
+                  const node = childType.toDom(this.opts.document, this.opts.hooks, this)
+                  dom.insertBefore(node, currentChild)
+                  break
+                case false:
+                  // nop
+                  break
+                default:
+                  // Is already attached to the dom.
+                  // Find it and remove all dom nodes in-between.
+                  removeDomChildrenUntilElementFound(dom, currentChild, childNode)
+                  currentChild = childNode.nextSibling
+                  break
+              }
+            })
+            removeDomChildrenUntilElementFound(dom, currentChild, null)
+          }
+        }
+      }
+    })
+    fixScroll(this.scrollingElement, scrollRef)
+  })
+}
--- a/src/Bindings/DomBinding/util.mjs
+++ b/src/Bindings/DomBinding/util.mjs
@@ -0,0 +1,124 @@
+
+import domToType from './domToType.mjs'
+
+/**
+ * Iterates items until an undeleted item is found.
+ *
+ * @private
+ */
+export function iterateUntilUndeleted (item) {
+  while (item !== null && item._deleted) {
+    item = item._right
+  }
+  return item
+}
+
+/**
+ * Removes an association (the information that a DOM element belongs to a
+ * type).
+ *
+ * @param {DomBinding} domBinding The binding object
+ * @param {Element} dom The dom that is to be associated with type
+ * @param {YXmlElement|YXmlHook} type The type that is to be associated with dom
+ *
+ */
+export function removeAssociation (domBinding, dom, type) {
+  domBinding.domToType.delete(dom)
+  domBinding.typeToDom.delete(type)
+}
+
+/**
+ * Creates an association (the information that a DOM element belongs to a
+ * type).
+ *
+ * @param {DomBinding} domBinding The binding object
+ * @param {Element} dom The dom that is to be associated with type
+ * @param {YXmlElement|YXmlHook} type The type that is to be associated with dom
+ *
+ */
+export function createAssociation (domBinding, dom, type) {
+  if (domBinding !== undefined) {
+    domBinding.domToType.set(dom, type)
+    domBinding.typeToDom.set(type, dom)
+  }
+}
+
+/**
+ * If oldDom is associated with a type, associate newDom with the type and
+ * forget about oldDom. If oldDom is not associated with any type, nothing happens.
+ *
+ * @param {DomBinding} domBinding The binding object
+ * @param {Element} oldDom The existing dom
+ * @param {Element} newDom The new dom object
+ */
+export function switchAssociation (domBinding, oldDom, newDom) {
+  if (domBinding !== undefined) {
+    const type = domBinding.domToType.get(oldDom)
+    if (type !== undefined) {
+      removeAssociation(domBinding, oldDom, type)
+      createAssociation(domBinding, newDom, type)
+    }
+  }
+}
+
+/**
+ * Insert Dom Elements after one of the children of this YXmlFragment.
+ * The Dom elements will be bound to a new YXmlElement and inserted at the
+ * specified position.
+ *
+ * @param {YXmlElement} type The type in which to insert DOM elements.
+ * @param {YXmlElement|null} prev The reference node. New YxmlElements are
+ *                           inserted after this node. Set null to insert at
+ *                           the beginning.
+ * @param {Array<Element>} doms The Dom elements to insert.
+ * @param {?Document} _document Optional. Provide the global document object.
+ * @param {DomBinding} binding The dom binding
+ * @return {Array<YXmlElement>} The YxmlElements that are inserted.
+ *
+ * @private
+ */
+export function insertDomElementsAfter (type, prev, doms, _document, binding) {
+  const types = domsToTypes(doms, _document, binding.opts.hooks, binding.filter, binding)
+  return type.insertAfter(prev, types)
+}
+
+export function domsToTypes (doms, _document, hooks, filter, binding) {
+  const types = []
+  for (let dom of doms) {
+    const t = domToType(dom, _document, hooks, filter, binding)
+    if (t !== false) {
+      types.push(t)
+    }
+  }
+  return types
+}
+
+/**
+ * @private
+ */
+export function insertNodeHelper (yxml, prevExpectedNode, child, _document, binding) {
+  let insertedNodes = insertDomElementsAfter(yxml, prevExpectedNode, [child], _document, binding)
+  if (insertedNodes.length > 0) {
+    return insertedNodes[0]
+  } else {
+    return prevExpectedNode
+  }
+}
+
+/**
+ * Remove children until `elem` is found.
+ *
+ * @param {Element} parent The parent of `elem` and `currentChild`.
+ * @param {Element} currentChild Start removing elements with `currentChild`. If
+ *                               `currentChild` is `elem` it won't be removed.
+ * @param {Element|null} elem The elemnt to look for.
+ *
+ * @private
+ */
+export function removeDomChildrenUntilElementFound (parent, currentChild, elem) {
+  while (currentChild !== elem) {
+    const del = currentChild
+    currentChild = currentChild.nextSibling
+    parent.removeChild(del)
+  }
+}
--- a/src/Bindings/QuillBinding/QuillBinding.mjs
+++ b/src/Bindings/QuillBinding/QuillBinding.mjs
@@ -0,0 +1,53 @@
+import Binding from '../Binding.mjs'
+
+function typeObserver (event) {
+  const quill = this.target
+  // Force flush Quill changes.
+  quill.update('yjs')
+  this._mutualExclude(function () {
+    // Apply computed delta.
+    quill.updateContents(event.delta, 'yjs')
+    // Force flush Quill changes. Ignore applied changes.
+    quill.update('yjs')
+  })
+}
+
+function quillObserver (delta) {
+  this._mutualExclude(() => {
+    this.type.applyDelta(delta.ops)
+  })
+}
+
+/**
+ * A Binding that binds a YText type to a Quill editor.
+ *
+ * @example
+ * const quill = new Quill(document.createElement('div'))
+ * const type = y.define('quill', Y.Text)
+ * const binding = new Y.QuillBinding(quill, type)
+ * // Now modifications on the DOM will be reflected in the Type, and the other
+ * // way around!
+ */
+export default class QuillBinding extends Binding {
+  /**
+   * @param {YText} textType
+   * @param {Quill} quill
+   */
+  constructor (textType, quill) {
+    // Binding handles textType as this.type and quill as this.target.
+    super(textType, quill)
+    // Set initial value.
+    quill.setContents(textType.toDelta(), 'yjs')
+    // Observers are handled by this class.
+    this._typeObserver = typeObserver.bind(this)
+    this._quillObserver = quillObserver.bind(this)
+    textType.observe(this._typeObserver)
+    quill.on('text-change', this._quillObserver)
+  }
+  destroy () {
+    // Remove everything that is handled by this class.
+    this.type.unobserve(this._typeObserver)
+    this.target.off('text-change', this._quillObserver)
+    super.destroy()
+  }
+}
--- a/src/Bindings/TextareaBinding/TextareaBinding.mjs
+++ b/src/Bindings/TextareaBinding/TextareaBinding.mjs
@@ -0,0 +1,56 @@
+
+import Binding from '../Binding.mjs'
+import simpleDiff from '../../Util/simpleDiff.mjs'
+import { getRelativePosition, fromRelativePosition } from '../../Util/relativePosition.mjs'
+
+function typeObserver () {
+  this._mutualExclude(() => {
+    const textarea = this.target
+    const textType = this.type
+    const relativeStart = getRelativePosition(textType, textarea.selectionStart)
+    const relativeEnd = getRelativePosition(textType, textarea.selectionEnd)
+    textarea.value = textType.toString()
+    const start = fromRelativePosition(textType._y, relativeStart)
+    const end = fromRelativePosition(textType._y, relativeEnd)
+    textarea.setSelectionRange(start, end)
+  })
+}
+
+function domObserver () {
+  this._mutualExclude(() => {
+    let diff = simpleDiff(this.type.toString(), this.target.value)
+    this.type.delete(diff.pos, diff.remove)
+    this.type.insert(diff.pos, diff.insert)
+  })
+}
+
+/**
+ * A binding that binds a YText to a dom textarea.
+ *
+ * This binding is automatically destroyed when its parent is deleted.
+ *
+ * @example
+ *   const textare = document.createElement('textarea')
+ *   const type = y.define('textarea', Y.Text)
+ *   const binding = new Y.QuillBinding(type, textarea)
+ *
+ */
+export default class TextareaBinding extends Binding {
+  constructor (textType, domTextarea) {
+    // Binding handles textType as this.type and domTextarea as this.target
+    super(textType, domTextarea)
+    // set initial value
+    domTextarea.value = textType.toString()
+    // Observers are handled by this class
+    this._typeObserver = typeObserver.bind(this)
+    this._domObserver = domObserver.bind(this)
+    textType.observe(this._typeObserver)
+    domTextarea.addEventListener('input', this._domObserver)
+  }
+  destroy () {
+    // Remove everything that is handled by this class
+    this.type.unobserve(this._typeObserver)
+    this.target.unobserve(this._domObserver)
+    super.destroy()
+  }
+}
--- a/src/Connector.mjs
+++ b/src/Connector.mjs
@@ -1,12 +1,14 @@
-import BinaryEncoder from './Binary/Encoder.js'
-import BinaryDecoder from './Binary/Decoder.js'
+import BinaryEncoder from './Util/Binary/Encoder.mjs'
+import BinaryDecoder from './Util/Binary/Decoder.mjs'

-import { sendSyncStep1, readSyncStep1 } from './MessageHandler/syncStep1.js'
-import { readSyncStep2 } from './MessageHandler/syncStep2.js'
-import { integrateRemoteStructs } from './MessageHandler/integrateRemoteStructs.js'
+import { sendSyncStep1, readSyncStep1 } from './MessageHandler/syncStep1.mjs'
+import { readSyncStep2 } from './MessageHandler/syncStep2.mjs'
+import { integrateRemoteStructs } from './MessageHandler/integrateRemoteStructs.mjs'

 import debug from 'debug'

+// TODO: rename Connector
+
 export default class AbstractConnector {
  constructor (y, opts) {
    this.y = y
@@ -132,6 +134,7 @@ export default class AbstractConnector {
        f()
      }
      this.whenSyncedListeners = []
+      this.y._setContentReady()
      this.y.emit('synced')
    }
  }
@@ -268,7 +271,7 @@ export default class AbstractConnector {
        if (messageType === 'sync step 2' && senderConn.auth === 'write') {
          readSyncStep2(decoder, encoder, y, senderConn, sender)
        } else if (messageType === 'update' && (skipAuth || senderConn.auth === 'write')) {
-          integrateRemoteStructs(decoder, encoder, y, senderConn, sender)
+          integrateRemoteStructs(y, decoder)
        } else {
          throw new Error('Unable to receive message')
        }
--- a/src/Connectors/WebsocketsConnector/WebsocketsConnector.mjs
+++ b/src/Connectors/WebsocketsConnector/WebsocketsConnector.mjs
@@ -0,0 +1,140 @@
+import BinaryEncoder from '../../Util/Binary/Encoder.mjs'
+/* global WebSocket */
+import NamedEventHandler from '../../Util/NamedEventHandler.mjs'
+import decodeMessage, { messageSS, messageSubscribe, messageStructs } from './decodeMessage.mjs'
+import { createMutualExclude } from '../../Util/mutualExclude.mjs'
+import { messageCheckUpdateCounter } from './decodeMessage.mjs'
+
+export const STATE_DISCONNECTED = 0 
+export const STATE_CONNECTED = 1
+
+export default class WebsocketsConnector extends NamedEventHandler {
+  constructor (url = 'ws://localhost:1234') {
+    super()
+    this.url = url
+    this._state = STATE_DISCONNECTED
+    this._socket = null
+    this._rooms = new Map()
+    this._connectToServer = true
+    this._reconnectTimeout = 300
+    this._mutualExclude = createMutualExclude()
+    this._persistence = null
+    this.connect()
+  }
+
+  getRoom (roomName) {
+    return this._rooms.get(roomName) || { y: null, roomName, localUpdateCounter: 1 }
+  }
+
+  syncPersistence (persistence) {
+    this._persistence = persistence
+    if (this._state === STATE_CONNECTED) {
+      persistence.getAllDocuments().then(docs => {
+        const encoder = new BinaryEncoder()
+        docs.forEach(doc => {
+          messageCheckUpdateCounter(doc.roomName, encoder, doc.remoteUpdateCounter)
+        });
+        this.send(encoder)
+      })
+    }
+  }
+
+  connectY (roomName, y) {
+    let room = this._rooms.get(roomName)
+    if (room !== undefined) {
+      throw new Error('Room is already taken! There can be only one Yjs instance per roomName!')
+    }
+    this._rooms.set(roomName, {
+      roomName,
+      y,
+      localUpdateCounter: 1
+    })
+    y.on('afterTransaction', (y, transaction) => {
+      this._mutualExclude(() => {
+        if (transaction.encodedStructsLen > 0) {
+          const encoder = new BinaryEncoder()
+          const room = this._rooms.get(roomName)
+          messageStructs(roomName, y, encoder, transaction.encodedStructs, ++room.localUpdateCounter)
+          this.send(encoder)
+        }
+      })
+    })
+    if (this._state === STATE_CONNECTED) {
+      const encoder = new BinaryEncoder()
+      messageSS(roomName, y, encoder)
+      messageSubscribe(roomName, y, encoder)
+      this.send(encoder)
+    }
+  }
+
+  _setState (state) {
+    this._state = state
+    this.emit('stateChanged', {
+      state: this.state
+    })
+  }
+
+  get state () {
+    return this._state === STATE_DISCONNECTED ? 'disconnected' : 'connected'
+  }
+
+  _onOpen () {
+    this._setState(STATE_CONNECTED)
+    if (this._persistence === null) {
+      const encoder = new BinaryEncoder()
+      for (const [roomName, room] of this._rooms) {
+        const y = room.y
+        messageSS(roomName, y, encoder)
+        messageSubscribe(roomName, y, encoder)
+      }
+      this.send(encoder)
+    } else {
+      this.syncPersistence(this._persistence)
+    }
+  }
+
+  send (encoder) {
+    if (encoder.length > 0 && this._socket.readyState === WebSocket.OPEN) {
+      this._socket.send(encoder.createBuffer())
+    }
+  }
+
+  _onClose () {
+    this._setState(STATE_DISCONNECTED)
+    this._socket = null
+    if (this._connectToServer) {
+      setTimeout(() => {
+        if (this._connectToServer) {
+          this.connect()
+        }
+      }, this._reconnectTimeout)
+      this.connect()
+    }
+  }
+
+  _onMessage (message) {
+    if (message.data.byteLength > 0) {
+      const reply = decodeMessage(this, message.data, null, false, this._persistence)
+      this.send(reply)
+    }
+  }
+
+  disconnect (code = 1000, reason = 'Client manually disconnected') {
+    const socket = this._socket
+    this._connectToServer = false
+    socket.close(code, reason)
+  }
+
+  connect () {
+    if (this._socket === null) {
+      const socket = new WebSocket(this.url)
+      socket.binaryType = 'arraybuffer'
+      this._socket = socket
+      this._connectToServer = true
+      // Connection opened
+      socket.addEventListener('open', this._onOpen.bind(this))
+      socket.addEventListener('close', this._onClose.bind(this))
+      socket.addEventListener('message', this._onMessage.bind(this))
+    }
+  }
+}
--- a/src/Connectors/WebsocketsConnector/decodeMessage.mjs
+++ b/src/Connectors/WebsocketsConnector/decodeMessage.mjs
@@ -0,0 +1,159 @@
+import BinaryDecoder from '../../Util/Binary/Decoder.mjs'
+import BinaryEncoder from '../../Util/Binary/Encoder.mjs'
+import { readStateSet, writeStateSet } from '../../MessageHandler/stateSet.mjs'
+import { writeStructs } from '../../MessageHandler/syncStep1.mjs'
+import { writeDeleteSet, readDeleteSet } from '../../MessageHandler/deleteSet.mjs'
+import { integrateRemoteStructs } from '../../MessageHandler/integrateRemoteStructs.mjs'
+
+const CONTENT_GET_SS = 4
+export function messageGetSS (roomName, y, encoder) {
+  encoder.writeVarString(roomName)
+  encoder.writeVarUint(CONTENT_GET_SS)
+}
+
+const CONTENT_SUBSCRIBE = 3
+export function messageSubscribe (roomName, y, encoder) {
+  encoder.writeVarString(roomName)
+  encoder.writeVarUint(CONTENT_SUBSCRIBE)
+}
+
+const CONTENT_SS = 0
+export function messageSS (roomName, y, encoder) {
+  encoder.writeVarString(roomName)
+  encoder.writeVarUint(CONTENT_SS)
+  writeStateSet(y, encoder)
+}
+
+const CONTENT_STRUCTS_DSS = 2
+export function messageStructsDSS (roomName, y, encoder, ss, updateCounter) {
+  encoder.writeVarString(roomName)
+  encoder.writeVarUint(CONTENT_STRUCTS_DSS)
+  encoder.writeVarUint(updateCounter)
+  const structsDS = new BinaryEncoder()
+  writeStructs(y, structsDS, ss)
+  writeDeleteSet(y, structsDS)
+  encoder.writeVarUint(structsDS.length)
+  encoder.writeBinaryEncoder(structsDS)
+}
+
+const CONTENT_STRUCTS = 5
+export function messageStructs (roomName, y, encoder, structsBinaryEncoder, updateCounter) {
+  encoder.writeVarString(roomName)
+  encoder.writeVarUint(CONTENT_STRUCTS)
+  encoder.writeVarUint(updateCounter)
+  encoder.writeVarUint(structsBinaryEncoder.length)
+  encoder.writeBinaryEncoder(structsBinaryEncoder)
+}
+
+const CONTENT_CHECK_COUNTER = 6
+export function messageCheckUpdateCounter (roomName, encoder, updateCounter = 0) {
+  encoder.writeVarString(roomName)
+  encoder.writeVarUint(CONTENT_CHECK_COUNTER)
+  encoder.writeVarUint(updateCounter)
+}
+
+/**
+ * Decodes a client-message.
+ *
+ * A client-message consists of multiple message-elements that are concatenated without delimiter.
+ * Each has the following structure:
+ * - roomName
+ * - content_type
+ * - content (additional info that is encoded based on the value of content_type)
+ *
+ * The message is encoded until no more message-elements are available.
+ *
+ * @param {*} connector The connector that handles the connections
+ * @param {*} message The binary encoded message
+ * @param {*} ws The connection object
+ */
+export default function decodeMessage (connector, message, ws, isServer = false, persistence) {
+  const decoder = new BinaryDecoder(message)
+  const encoder = new BinaryEncoder()
+  while (decoder.hasContent()) {
+    const roomName = decoder.readVarString()
+    const contentType = decoder.readVarUint()
+    const room = connector.getRoom(roomName)
+    const y = room.y
+    switch (contentType) {
+      case CONTENT_CHECK_COUNTER:
+        const updateCounter = decoder.readVarUint()
+        if (room.localUpdateCounter !== updateCounter) {
+          messageGetSS(roomName, y, encoder)
+        }
+        connector.subscribe(roomName, ws)
+        break
+      case CONTENT_STRUCTS:
+        console.log(`${roomName}: received update`)
+        connector._mutualExclude(() => {
+          const remoteUpdateCounter = decoder.readVarUint()
+          persistence.setRemoteUpdateCounter(roomName, remoteUpdateCounter)
+          const messageLen = decoder.readVarUint()
+          if (y === null) {
+            persistence._persistStructs(roomName, decoder.readArrayBuffer(messageLen))
+          } else {
+            y.transact(() => {
+              integrateRemoteStructs(y, decoder)
+            }, true)
+          }
+        })
+        break
+      case CONTENT_GET_SS:
+        if (y !== null) {
+          messageSS(roomName, y, encoder)
+        } else {
+          persistence._createYInstance(roomName).then(y => {
+            const encoder = new BinaryEncoder()
+            messageSS(roomName, y, encoder)
+            connector.send(encoder, ws)
+          })
+        }
+        break
+      case CONTENT_SUBSCRIBE:
+        connector.subscribe(roomName, ws)
+        break
+      case CONTENT_SS:
+        // received state set
+        // reply with missing content
+        const ss = readStateSet(decoder)
+        const sendStructsDSS = () => {
+          if (y !== null) { // TODO: how to sync local content?
+            const encoder = new BinaryEncoder()
+            messageStructsDSS(roomName, y, encoder, ss, room.localUpdateCounter) // room.localUpdateHandler in case it changes
+            if (isServer) {
+              messageSS(roomName, y, encoder)
+            }
+            connector.send(encoder, ws)
+          }
+        }
+        if (room.persistenceLoaded !== undefined) {
+          room.persistenceLoaded.then(sendStructsDSS)
+        } else {
+          sendStructsDSS()
+        }
+        break
+      case CONTENT_STRUCTS_DSS:
+        console.log(`${roomName}: synced`)
+        connector._mutualExclude(() => {
+          const remoteUpdateCounter = decoder.readVarUint()
+          persistence.setRemoteUpdateCounter(roomName, remoteUpdateCounter)
+          const messageLen = decoder.readVarUint()
+          if (y === null) {
+            persistence._persistStructsDS(roomName, decoder.readArrayBuffer(messageLen))
+          } else {
+            y.transact(() => {
+              integrateRemoteStructs(y, decoder)
+              readDeleteSet(y, decoder)
+            }, true)
+          }
+        })
+        break
+      default:
+        console.error('Unexpected content type!')
+        if (ws !== null) {
+          ws.close() // TODO: specify reason
+        }
+    }
+  }
+  return encoder
+}
--- a/src/Connectors/WebsocketsConnector/server.mjs
+++ b/src/Connectors/WebsocketsConnector/server.mjs
@@ -0,0 +1,124 @@
+import Y from '../../Y.mjs'
+import uws from 'uws'
+import BinaryEncoder from '../../Util/Binary/Encoder.mjs'
+import decodeMessage, { messageStructs } from './decodeMessage.mjs'
+import FilePersistence from '../../Persistences/FilePersistence.mjs'
+
+const WebsocketsServer = uws.Server
+const persistence = new FilePersistence('.yjsPersisted')
+/**
+  * Maps from room-name to ..
+  * {
+  *   connections, // Set of ws-clients that listen to the room
+  *   y            // Yjs instance that handles the room
+  * }
+  */
+const rooms = new Map()
+/**
+ * Maps from ws-connection to Set<roomName> - the set of connected roomNames
+ */
+const connections = new Map()
+const port = process.env.PORT || 1234
+const wss = new WebsocketsServer({
+  port,
+  perMessageDeflate: {}
+})
+
+/**
+ * Set of room names that are scheduled to be sweeped (destroyed because they don't have a connection anymore)
+ */
+const scheduledSweeps = new Set()
+/* TODO: enable sweeping
+setInterval(function sweepRoomes () {
+  scheduledSweeps.forEach(roomName => {
+    const room = rooms.get(roomName)
+    if (room !== undefined) {
+      if (room.connections.size === 0) {
+        persistence.saveState(roomName, room.y).then(() => {
+          if (room.connections.size === 0) {
+            room.y.destroy()
+            rooms.delete(roomName)
+          }
+        })
+      }
+    }
+  })
+  scheduledSweeps.clear()
+}, 5000) */ 
+
+const wsConnector = {
+  send: (encoder, ws) => {
+    const message = encoder.createBuffer()
+    ws.send(message, null, null, true)
+  },
+  _mutualExclude: f => { f() },
+  subscribe: function subscribe (roomName, ws) {
+    let roomNames = connections.get(ws)
+    if (roomNames === undefined) {
+      roomNames = new Set()
+      connections.set(ws, roomNames)
+    }
+    roomNames.add(roomName)
+    const room = this.getRoom(roomName)
+    room.connections.add(ws)
+  },
+  getRoom: function getRoom (roomName) {
+    let room = rooms.get(roomName)
+    if (room === undefined) {
+      const y = new Y(roomName, null, null, { gc: true })
+      const persistenceLoaded = persistence.readState(roomName, y)
+      room = {
+        name: roomName,
+        connections: new Set(),
+        y,
+        persistenceLoaded,
+        localUpdateCounter: 1
+      }
+      y.on('afterTransaction', (y, transaction) => {
+        if (transaction.encodedStructsLen > 0) {
+          // save to persistence
+          persistence.saveUpdate(roomName, y, transaction.encodedStructs)
+          // forward update to clients
+          persistence._mutex(() => { // do not broadcast if persistence.readState is called
+            const encoder = new BinaryEncoder()
+            messageStructs(roomName, y, encoder, transaction.encodedStructs, ++room.localUpdateCounter)
+            const message = encoder.createBuffer()
+            // when changed, broakcast update to all connections
+            room.connections.forEach(conn => {
+              conn.send(message, null, null, true)
+            })
+          })
+        }
+      })
+      rooms.set(roomName, room)
+    }
+    return room
+  }
+}
+
+wss.on('connection', (ws) => {
+  ws.on('message', function onWSMessage (message) {
+    if (message.byteLength > 0) {
+      const reply = decodeMessage(wsConnector, message, ws, true, persistence)
+      if (reply.length > 0) {
+        ws.send(reply.createBuffer(), null, null, true)
+      }
+    }
+  })
+  ws.on('close', function onWSClose () {
+    const roomNames = connections.get(ws)
+    if (roomNames !== undefined) {
+      roomNames.forEach(roomName => {
+        const room = rooms.get(roomName)
+        if (room !== undefined) {
+          const connections = room.connections
+          connections.delete(ws)
+          if (connections.size === 0) {
+            scheduledSweeps.add(roomName)
+          }
+        }
+      })
+      connections.delete(ws)
+    }
+  })
+})
--- a/src/MessageHandler/binaryEncode.mjs
+++ b/src/MessageHandler/binaryEncode.mjs
@@ -0,0 +1,32 @@
+
+import { writeStructs } from './syncStep1.mjs'
+import { integrateRemoteStructs } from './integrateRemoteStructs.mjs'
+import { readDeleteSet, writeDeleteSet } from './deleteSet.mjs'
+import BinaryEncoder from '../Util/Binary/Encoder.mjs'
+
+/**
+ * Read the Decoder and fill the Yjs instance with data in the decoder.
+ *
+ * @param {Y} y The Yjs instance
+ * @param {BinaryDecoder} decoder The BinaryDecoder to read from.
+ */
+export function fromBinary (y, decoder) {
+  y.transact(function () {
+    integrateRemoteStructs(y, decoder)
+    readDeleteSet(y, decoder)
+  })
+}
+
+/**
+ * Encode the Yjs model to binary format.
+ *
+ * @param {Y} y The Yjs instance
+ * @return {BinaryEncoder} The encoder instance that can be transformed
+ *                         to ArrayBuffer or Buffer.
+ */
+export function toBinary (y) {
+  let encoder = new BinaryEncoder()
+  writeStructs(y, encoder, new Map())
+  writeDeleteSet(y, encoder)
+  return encoder
+}
--- a/src/MessageHandler/deleteSet.mjs
+++ b/src/MessageHandler/deleteSet.mjs
@@ -1,5 +1,5 @@
-import { deleteItemRange } from '../Struct/Delete.js'
-import ID from '../Util/ID.js'
+import { deleteItemRange } from '../Struct/Delete.mjs'
+import ID from '../Util/ID/ID.mjs'

 export function stringifyDeleteSet (y, decoder, strBuilder) {
  let dsLength = decoder.readUint32()
@@ -92,7 +92,7 @@ export function readDeleteSet (y, decoder) {
            // delete maximum the len of d
            // else delete as much as possible
            diff = Math.min(n._id.clock - d[0], d[1])
-            // deleteItemRange(y, user, d[0], diff)
+            // deleteItemRange(y, user, d[0], diff, true)
            deletions.push([user, d[0], diff])
          } else {
            // 3)
@@ -100,7 +100,7 @@ export function readDeleteSet (y, decoder) {
            if (d[2] && !n.gc) {
              // d marks as gc'd but n does not
              // then delete either way
-              // deleteItemRange(y, user, d[0], Math.min(diff, d[1]))
+              // deleteItemRange(y, user, d[0], Math.min(diff, d[1]), true)
              deletions.push([user, d[0], Math.min(diff, d[1])])
            }
          }
@@ -117,12 +117,12 @@ export function readDeleteSet (y, decoder) {
      // Adapt the Tree implementation to support delete while iterating
      for (let i = deletions.length - 1; i >= 0; i--) {
        const del = deletions[i]
-        deleteItemRange(y, del[0], del[1], del[2])
+        deleteItemRange(y, del[0], del[1], del[2], true)
      }
      // for the rest.. just apply it
      for (; pos < dv.length; pos++) {
        d = dv[pos]
-        deleteItemRange(y, user, d[0], d[1])
+        deleteItemRange(y, user, d[0], d[1], true)
        // deletions.push([user, d[0], d[1], d[2]])
      }
    }
--- a/src/MessageHandler/integrateRemoteStructs.mjs
+++ b/src/MessageHandler/integrateRemoteStructs.mjs
@@ -1,6 +1,7 @@
-import { getStruct } from '../Util/structReferences.js'
-import BinaryDecoder from '../Binary/Decoder.js'
-import { logID } from './messageToString.js'
+import { getStruct } from '../Util/structReferences.mjs'
+import BinaryDecoder from '../Util/Binary/Decoder.mjs'
+import { logID } from './messageToString.mjs'
+import GC from '../Struct/GC.mjs'

 class MissingEntry {
  constructor (decoder, missing, struct) {
@@ -11,6 +12,7 @@ class MissingEntry {
 }

 /**
+ * @private
 * Integrate remote struct
 * When a remote struct is integrated, other structs might be ready to ready to
 * integrate.
@@ -23,7 +25,14 @@ function _integrateRemoteStructHelper (y, struct) {
    if (y.ss.getState(id.user) > id.clock) {
      return
    }
-    struct._integrate(y)
+    if (!y.gcEnabled || struct.constructor === GC || (struct._parent.constructor !== GC && struct._parent._deleted === false)) {
+      // Is either a GC or Item with an undeleted parent
+      // save to integrate
+      struct._integrate(y)
+    } else {
+      // Is an Item. parent was deleted.
+      struct._gc(y)
+    }
    let msu = y._missingStructs.get(id.user)
    if (msu != null) {
      let clock = id.clock
@@ -65,7 +74,7 @@ export function stringifyStructs (y, decoder, strBuilder) {
  }
 }

-export function integrateRemoteStructs (decoder, encoder, y) {
+export function integrateRemoteStructs (y, decoder) {
  const len = decoder.readUint32()
  for (let i = 0; i < len; i++) {
    let reference = decoder.readVarUint()
--- a/src/MessageHandler/messageToString.mjs
+++ b/src/MessageHandler/messageToString.mjs
@@ -1,10 +1,10 @@
-import BinaryDecoder from '../Binary/Decoder.js'
-import { stringifyStructs } from './integrateRemoteStructs.js'
-import { stringifySyncStep1 } from './syncStep1.js'
-import { stringifySyncStep2 } from './syncStep2.js'
-import ID from '../Util/ID.js'
-import RootID from '../Util/RootID.js'
-import Y from '../Y.js'
+import BinaryDecoder from '../Util/Binary/Decoder.mjs'
+import { stringifyStructs } from './integrateRemoteStructs.mjs'
+import { stringifySyncStep1 } from './syncStep1.mjs'
+import { stringifySyncStep2 } from './syncStep2.mjs'
+import ID from '../Util/ID/ID.mjs'
+import RootID from '../Util/ID/RootID.mjs'
+import Y from '../Y.mjs'

 export function messageToString ([y, buffer]) {
  let decoder = new BinaryDecoder(buffer)
@@ -46,3 +46,20 @@ export function logID (id) {
    throw new Error('This is not a valid ID!')
  }
 }
+
+/**
+ * Helper utility to convert an item to a readable format.
+ *
+ * @param {String} name The name of the item class (YText, ItemString, ..).
+ * @param {Item} item The item instance.
+ * @param {String} [append] Additional information to append to the returned
+ *                          string.
+ * @return {String} A readable string that represents the item object.
+ *
+ * @private
+ */
+export function logItemHelper (name, item, append) {
+  const left = item._left !== null ? item._left._lastId : null
+  const origin = item._origin !== null ? item._origin._lastId : null
+  return `${name}(id:${logID(item._id)},left:${logID(left)},origin:${logID(origin)},right:${logID(item._right)},parent:${logID(item._parent)},parentSub:${item._parentSub}${append !== undefined ? ' - ' + append : ''})`
+}
--- a/src/MessageHandler/stateSet.mjs
+++ b/src/MessageHandler/stateSet.mjs
--- a/src/MessageHandler/syncStep1.mjs
+++ b/src/MessageHandler/syncStep1.mjs
@@ -1,8 +1,8 @@
-import BinaryEncoder from '../Binary/Encoder.js'
-import { readStateSet, writeStateSet } from './stateSet.js'
-import { writeDeleteSet } from './deleteSet.js'
-import ID from '../Util/ID.js'
-import { RootFakeUserID } from '../Util/RootID.js'
+import BinaryEncoder from '../Util/Binary/Encoder.mjs'
+import { readStateSet, writeStateSet } from './stateSet.mjs'
+import { writeDeleteSet } from './deleteSet.mjs'
+import ID from '../Util/ID/ID.mjs'
+import { RootFakeUserID } from '../Util/ID/RootID.mjs'

 export function stringifySyncStep1 (y, decoder, strBuilder) {
  let auth = decoder.readVarString()
@@ -30,14 +30,27 @@ export function sendSyncStep1 (connector, syncUser) {
  connector.send(syncUser, encoder.createBuffer())
 }

-export default function writeStructs (encoder, decoder, y, ss) {
+/**
+ * @private
+ * Write all Items that are not not included in ss to
+ * the encoder object.
+ */
+export function writeStructs (y, encoder, ss) {
  const lenPos = encoder.pos
  encoder.writeUint32(0)
  let len = 0
  for (let user of y.ss.state.keys()) {
    let clock = ss.get(user) || 0
    if (user !== RootFakeUserID) {
-      y.os.iterate(new ID(user, clock), new ID(user, Number.MAX_VALUE), function (struct) {
+      const minBound = new ID(user, clock)
+      const overlappingLeft = y.os.findPrev(minBound)
+      const rightID = overlappingLeft === null ? null : overlappingLeft._id
+      if (rightID !== null && rightID.user === user && rightID.clock + overlappingLeft._length > clock) {
+        const struct = overlappingLeft._clonePartial(clock - rightID.clock)
+        struct._toBinary(encoder)
+        len++
+      }
+      y.os.iterate(minBound, new ID(user, Number.MAX_VALUE), function (struct) {
        struct._toBinary(encoder)
        len++
      })
@@ -60,7 +73,7 @@ export function readSyncStep1 (decoder, encoder, y, senderConn, sender) {
  encoder.writeVarString('sync step 2')
  encoder.writeVarString(y.connector.authInfo || '')
  const ss = readStateSet(decoder)
-  writeStructs(encoder, decoder, y, ss)
+  writeStructs(y, encoder, ss)
  writeDeleteSet(y, encoder)
  y.connector.send(senderConn.uid, encoder.createBuffer())
  senderConn.receivedSyncStep2 = true
--- a/src/MessageHandler/syncStep2.mjs
+++ b/src/MessageHandler/syncStep2.mjs
@@ -1,5 +1,5 @@
-import { stringifyStructs, integrateRemoteStructs } from './integrateRemoteStructs.js'
-import { readDeleteSet } from './deleteSet.js'
+import { stringifyStructs, integrateRemoteStructs } from './integrateRemoteStructs.mjs'
+import { readDeleteSet } from './deleteSet.mjs'

 export function stringifySyncStep2 (y, decoder, strBuilder) {
  strBuilder.push('     - auth: ' + decoder.readVarString())
@@ -22,7 +22,7 @@ export function stringifySyncStep2 (y, decoder, strBuilder) {
 }

 export function readSyncStep2 (decoder, encoder, y, senderConn, sender) {
-  integrateRemoteStructs(decoder, encoder, y)
+  integrateRemoteStructs(y, decoder)
  readDeleteSet(y, decoder)
  y.connector._setSyncedWith(sender)
 }
--- a/src/Persistence.js
+++ b/src/Persistence.js
@@ -1,47 +0,0 @@
-// import BinaryEncoder from './Binary/Encoder.js'
-
-export default function extendPersistence (Y) {
-  class AbstractPersistence {
-    constructor (y, opts) {
-      this.y = y
-      this.opts = opts
-      this.saveOperationsBuffer = []
-      this.log = Y.debug('y:persistence')
-    }
-
-    saveToMessageQueue (binary) {
-      this.log('Room %s: Save message to message queue', this.y.options.connector.room)
-    }
-
-    saveOperations (ops) {
-      ops = ops.map(function (op) {
-        return Y.Struct[op.struct].encode(op)
-      })
-      /*
-      const saveOperations = () => {
-        if (this.saveOperationsBuffer.length > 0) {
-          let encoder = new BinaryEncoder()
-          encoder.writeVarString(this.opts.room)
-          encoder.writeVarString('update')
-          let ops = this.saveOperationsBuffer
-          this.saveOperationsBuffer = []
-          let length = ops.length
-          encoder.writeUint32(length)
-          for (var i = 0; i < length; i++) {
-            let op = ops[i]
-            Y.Struct[op.struct].binaryEncode(encoder, op)
-          }
-          this.saveToMessageQueue(encoder.createBuffer())
-        }
-      }
-      */
-      if (this.saveOperationsBuffer.length === 0) {
-        this.saveOperationsBuffer = ops
-      } else {
-        this.saveOperationsBuffer = this.saveOperationsBuffer.concat(ops)
-      }
-    }
-  }
-
-  Y.AbstractPersistence = AbstractPersistence
-}
--- a/src/Persistence.mjs
+++ b/src/Persistence.mjs
@@ -0,0 +1,122 @@
+import BinaryEncoder from './Util/Binary/Encoder.mjs'
+import BinaryDecoder from './Util/Binary/Decoder.mjs'
+import { toBinary, fromBinary } from './MessageHandler/binaryEncode.mjs'
+import { integrateRemoteStructs } from './MessageHandler/integrateRemoteStructs.mjs'
+import { createMutualExclude } from './Util/mutualExclude.mjs'
+
+function getFreshCnf () {
+  let buffer = new BinaryEncoder()
+  buffer.writeUint32(0)
+  return {
+    len: 0,
+    buffer
+  }
+}
+
+/**
+ * Abstract persistence class.
+ */
+export default class AbstractPersistence {
+  constructor (opts) {
+    this.opts = opts
+    this.ys = new Map()
+  }
+
+  _init (y) {
+    let cnf = this.ys.get(y)
+    if (cnf === undefined) {
+      cnf = getFreshCnf()
+      cnf.mutualExclude = createMutualExclude()
+      this.ys.set(y, cnf)
+      return this.init(y).then(() => {
+        y.on('afterTransaction', (y, transaction) => {
+          let cnf = this.ys.get(y)
+          if (cnf.len > 0) {
+            cnf.buffer.setUint32(0, cnf.len)
+            this.saveUpdate(y, cnf.buffer.createBuffer(), transaction)
+            let _cnf = getFreshCnf()
+            for (let key in _cnf) {
+              cnf[key] = _cnf[key]
+            }
+          }
+        })
+        return this.retrieve(y)
+      }).then(function () {
+        return Promise.resolve(cnf)
+      })
+    } else {
+      return Promise.resolve(cnf)
+    }
+  }
+  deinit (y) {
+    this.ys.delete(y)
+    y.persistence = null
+  }
+
+  destroy () {
+    this.ys = null
+  }
+
+  /**
+   * Remove all persisted data that belongs to a room.
+   * Automatically destroys all Yjs all Yjs instances that persist to
+   * the room. If `destroyYjsInstances = false` the persistence functionality
+   * will be removed from the Yjs instances.
+   *
+   * ** Must be overwritten! **
+   */
+  removePersistedData (room, destroyYjsInstances = true) {
+    this.ys.forEach((cnf, y) => {
+      if (y.room === room) {
+        if (destroyYjsInstances) {
+          y.destroy()
+        } else {
+          this.deinit(y)
+        }
+      }
+    })
+  }
+
+  /* overwrite */
+  saveUpdate (buffer) {
+  }
+
+  /**
+   * Save struct to update buffer.
+   * saveUpdate is called when transaction ends
+   */
+  saveStruct (y, struct) {
+    let cnf = this.ys.get(y)
+    if (cnf !== undefined) {
+      cnf.mutualExclude(function () {
+        struct._toBinary(cnf.buffer)
+        cnf.len++
+      })
+    }
+  }
+
+  /* overwrite */
+  retrieve (y, model, updates) {
+    let cnf = this.ys.get(y)
+    if (cnf !== undefined) {
+      cnf.mutualExclude(function () {
+        y.transact(function () {
+          if (model != null) {
+            fromBinary(y, new BinaryDecoder(new Uint8Array(model)))
+          }
+          if (updates != null) {
+            for (let i = 0; i < updates.length; i++) {
+              integrateRemoteStructs(y, new BinaryDecoder(new Uint8Array(updates[i])))
+            }
+          }
+        })
+        y.emit('persistenceReady')
+      })
+    }
+  }
+
+  /* overwrite */
+  persist (y) {
+    return toBinary(y).createBuffer()
+  }
+}
--- a/src/Persistences/AbstractPersistence.mjs
+++ b/src/Persistences/AbstractPersistence.mjs
@@ -0,0 +1,2 @@
+
+export default class AbstractPersistence {}
--- a/src/Persistences/FilePersistence.mjs
+++ b/src/Persistences/FilePersistence.mjs
@@ -0,0 +1,72 @@
+import fs from 'fs'
+import path from 'path'
+import BinaryDecoder from '../Util/Binary/Decoder.mjs'
+import BinaryEncoder from '../Util/Binary/Encoder.mjs'
+import { createMutualExclude } from '../Util/mutualExclude.mjs'
+import { encodeUpdate, encodeStructsDS, decodePersisted } from './decodePersisted.mjs'
+
+function createFilePath (persistence, roomName) {
+  // TODO: filename checking!
+  return path.join(persistence.dir, roomName)
+}
+
+export default class FilePersistence {
+  constructor (dir) {
+    this.dir = dir
+    this._mutex = createMutualExclude()
+  }
+  setRemoteUpdateCounter (roomName, remoteUpdateCounter) {
+    // TODO: implement
+    // nop
+  }
+  saveUpdate (room, y, encodedStructs) {
+    return new Promise((resolve, reject) => {
+      this._mutex(() => {
+        const filePath = createFilePath(this, room)
+        const updateMessage = new BinaryEncoder()
+        encodeUpdate(y, encodedStructs, updateMessage)
+        fs.appendFile(filePath, Buffer.from(updateMessage.createBuffer()), (err) => {
+          if (err !== null) {
+            reject(err)
+          } else {
+            resolve()
+          }
+        })
+      }, resolve)
+    })
+  }
+  saveState (roomName, y) {
+    return new Promise((resolve, reject) => {
+      const encoder = new BinaryEncoder()
+      encodeStructsDS(y, encoder)
+      const filePath = createFilePath(this, roomName)
+      fs.writeFile(filePath, Buffer.from(encoder.createBuffer()), (err) => {
+        if (err !== null) {
+          reject(err)
+        } else {
+          resolve()
+        }
+      })
+    })
+  }
+  readState (roomName, y) {
+    // Check if the file exists in the current directory.
+    return new Promise((resolve, reject) => {
+      const filePath = path.join(this.dir, roomName)
+      fs.readFile(filePath, (err, data) => {
+        if (err !== null) {
+          resolve()
+          // reject(err)
+        } else {
+          this._mutex(() => {
+            console.info(`unpacking data (${data.length})`)
+            console.time('unpacking')
+            decodePersisted(y, new BinaryDecoder(data))
+            console.timeEnd('unpacking')
+          })
+          resolve()
+        }
+      })
+    })
+  }
+}
--- a/src/Persistences/IndexedDBPersistence.mjs
+++ b/src/Persistences/IndexedDBPersistence.mjs
@@ -0,0 +1,283 @@
+/* global indexedDB, location, BroadcastChannel */
+
+import Y from '../Y.mjs'
+import { createMutualExclude } from '../Util/mutualExclude.mjs'
+import { decodePersisted, encodeStructsDS, encodeUpdate } from './decodePersisted.mjs'
+import BinaryDecoder from '../Util/Binary/Decoder.mjs'
+import BinaryEncoder from '../Util/Binary/Encoder.mjs'
+import { PERSIST_STRUCTS_DS } from './decodePersisted.mjs';
+import { PERSIST_UPDATE } from './decodePersisted.mjs';
+/*
+ * Request to Promise transformer
+ */
+function rtop (request) {
+  return new Promise(function (resolve, reject) {
+    request.onerror = function (event) {
+      reject(new Error(event.target.error))
+    }
+    request.onblocked = function () {
+      location.reload()
+    }
+    request.onsuccess = function (event) {
+      resolve(event.target.result)
+    }
+  })
+}
+
+function openDB (room) {
+  return new Promise(function (resolve, reject) {
+    let request = indexedDB.open(room)
+    request.onupgradeneeded = function (event) {
+      const db = event.target.result
+      if (db.objectStoreNames.contains('updates')) {
+        db.deleteObjectStore('updates')
+      }
+      db.createObjectStore('updates', {autoIncrement: true})
+    }
+    request.onerror = function (event) {
+      reject(new Error(event.target.error))
+    }
+    request.onblocked = function () {
+      location.reload()
+    }
+    request.onsuccess = function (event) {
+      const db = event.target.result
+      db.onversionchange = function () { db.close() }
+      resolve(db)
+    }
+  })
+}
+
+function persist (room) {
+  let t = room.db.transaction(['updates'], 'readwrite')
+  let updatesStore = t.objectStore('updates')
+  return rtop(updatesStore.getAll())
+  .then(updates => {
+    // apply all previous updates before deleting them
+    room.mutex(() => {
+      updates.forEach(update => {
+        decodePersisted(y, new BinaryDecoder(update))
+      })
+    })
+    const encoder = new BinaryEncoder()
+    encodeStructsDS(y, encoder)
+    // delete all pending updates
+    rtop(updatesStore.clear()).then(() => {
+      // write current model
+      updatesStore.put(encoder.createBuffer())
+    })
+  })
+}
+
+function saveUpdate (room, updateBuffer) {
+  const db = room.db
+  if (db !== null) {
+    const t = db.transaction(['updates'], 'readwrite')
+    const updatesStore = t.objectStore('updates')
+    const updatePut = rtop(updatesStore.put(updateBuffer))
+    rtop(updatesStore.count()).then(cnt => {
+      if (cnt >= PREFERRED_TRIM_SIZE) {
+        persist(room)
+      }
+    })
+    return updatePut
+  }
+}
+
+function registerRoomInPersistence (documentsDB, roomName) {
+  return documentsDB.then(
+    db => Promise.all([
+      db,
+      rtop(db.transaction(['documents'], 'readonly').objectStore('documents').get(roomName))
+    ])
+  ).then(
+    ([db, doc]) => {
+      if (doc === undefined) {
+        return rtop(db.transaction(['documents'], 'readwrite').objectStore('documents').add({ roomName, serverUpdateCounter: 0 }))
+      }
+    }
+  )
+}
+
+const PREFERRED_TRIM_SIZE = 400
+
+export default class IndexedDBPersistence {
+  constructor () {
+    this._rooms = new Map()
+    this._documentsDB = new Promise(function (resolve, reject) {
+      let request = indexedDB.open('_yjs_documents')
+      request.onupgradeneeded = function (event) {
+        const db = event.target.result
+        if (db.objectStoreNames.contains('documents')) {
+          db.deleteObjectStore('documents')
+        }
+        db.createObjectStore('documents', { keyPath: "roomName" })
+      }
+      request.onerror = function (event) {
+        reject(new Error(event.target.error))
+      }
+      request.onblocked = function () {
+        location.reload()
+      }
+      request.onsuccess = function (event) {
+        const db = event.target.result
+        db.onversionchange = function () { db.close() }
+        resolve(db)
+      }
+    })
+    addEventListener('unload', () => {
+      // close everything when page unloads
+      this._rooms.forEach(room => {
+        if (room.db !== null) {
+          room.db.close()
+        } else {
+          room.dbPromise.then(db => db.close())
+        }
+      })
+      this._documentsDB.then(db => db.close())
+    })
+  }
+  getAllDocuments () {
+    return this._documentsDB.then(
+      db => rtop(db.transaction(['documents'], 'readonly').objectStore('documents').getAll())
+    )
+  }
+  setRemoteUpdateCounter (roomName, remoteUpdateCounter) {
+    this._documentsDB.then(
+      db => rtop(db.transaction(['documents'], 'readwrite').objectStore('documents').put({ roomName, remoteUpdateCounter }))
+    )
+  }
+
+  _createYInstance (roomName) {
+    const room = this._rooms.get(roomName)
+    if (room !== undefined) {
+      return room.y
+    }
+    const y = new Y()
+    return openDB(roomName).then(
+      db => rtop(db.transaction(['updates'], 'readonly').objectStore('updates').getAll())
+    ).then(
+      updates =>
+        y.transact(() => {
+          updates.forEach(update => {
+            decodePersisted(y, new BinaryDecoder(update))
+          })
+        }, true)
+    ).then(() => Promise.resolve(y))
+  }
+
+  _persistStructsDS (roomName, structsDS) {
+    const encoder = new BinaryEncoder()
+    encoder.writeVarUint(PERSIST_STRUCTS_DS)
+    encoder.writeArrayBuffer(structsDS)
+    return openDB(roomName).then(db => {
+      const t = db.transaction(['updates'], 'readwrite')
+      const updatesStore = t.objectStore('updates')
+      return rtop(updatesStore.put(encoder.createBuffer()))
+    })
+  }
+
+  _persistStructs (roomName, structs) {
+    const encoder = new BinaryEncoder()
+    encoder.writeVarUint(PERSIST_UPDATE)
+    encoder.writeArrayBuffer(structs)
+    return openDB(roomName).then(db => {
+      const t = db.transaction(['updates'], 'readwrite')
+      const updatesStore = t.objectStore('updates')
+      return rtop(updatesStore.put(encoder.createBuffer()))
+    })
+  }
+
+  connectY (roomName, y) {
+    if (this._rooms.has(roomName)) {
+      throw new Error('A Y instance is already bound to this room!')
+    }
+    let room = {
+      db: null,
+      dbPromise: null,
+      channel: null,
+      mutex: createMutualExclude(),
+      y
+    }
+    if (typeof BroadcastChannel !== 'undefined') {
+      room.channel = new BroadcastChannel('__yjs__' + roomName)
+      room.channel.addEventListener('message', e => {
+        room.mutex(function () {
+          decodePersisted(y, new BinaryDecoder(e.data))
+        })
+      })
+    }
+    y.on('destroyed', () => {
+      this.disconnectY(roomName, y)
+    })
+    y.on('afterTransaction', (y, transaction) => {
+      room.mutex(() => {
+        if (transaction.encodedStructsLen > 0) {
+          const encoder = new BinaryEncoder()
+          const update = new BinaryEncoder()
+          encodeUpdate(y, transaction.encodedStructs, update)
+          const updateBuffer = update.createBuffer()
+          if (room.channel !== null) {
+            room.channel.postMessage(updateBuffer)
+          }
+          if (transaction.encodedStructsLen > 0) {
+            if (room.db !== null) {
+              saveUpdate(room, updateBuffer)
+            }
+          }
+        }
+      })
+    })
+    // register document in documentsDB
+    this._documentsDB.then(
+      db => 
+        rtop(db.transaction(['documents'], 'readonly').objectStore('documents').get(roomName))
+          .then(
+            doc => doc === undefined && rtop(db.transaction(['documents'], 'readwrite').objectStore('documents').add({ roomName, serverUpdateCounter: -1 }))
+          )
+    )
+    // open room db and read existing data
+    return room.dbPromise = openDB(roomName)
+      .then(db => {
+        room.db = db
+        const t = room.db.transaction(['updates'], 'readwrite')
+        const updatesStore = t.objectStore('updates')
+        // write current state as update
+        const encoder = new BinaryEncoder()
+        encodeStructsDS(y, encoder)
+        return rtop(updatesStore.put(encoder.createBuffer())).then(() => {
+          // read persisted state
+          return rtop(updatesStore.getAll()).then(updates => {
+            room.mutex(() => {
+              y.transact(() => {
+                updates.forEach(update => {
+                  decodePersisted(y, new BinaryDecoder(update))
+                })
+              }, true)
+            })
+          })
+        })
+      })
+  }
+  disconnectY (roomName) {
+    const {
+      db, channel
+    } = this._rooms.get(roomName)
+    db.close()
+    if (channel !== null) {
+      channel.close()
+    }
+    this._rooms.delete(roomName)
+  }
+
+  /**
+   * Remove all persisted data that belongs to a room.
+   * Automatically destroys all Yjs all Yjs instances that persist to
+   * the room. If `destroyYjsInstances = false` the persistence functionality
+   * will be removed from the Yjs instances.
+   */
+  removePersistedData (roomName, destroyYjsInstances = true) {
+    this.disconnectY(roomName)
+    return rtop(indexedDB.deleteDatabase(roomName))
+  }
+}
--- a/src/Persistences/decodePersisted.mjs
+++ b/src/Persistences/decodePersisted.mjs
@@ -0,0 +1,51 @@
+import { integrateRemoteStructs } from '../MessageHandler/integrateRemoteStructs.mjs'
+import { writeStructs } from '../MessageHandler/syncStep1.mjs'
+import { writeDeleteSet, readDeleteSet } from '../MessageHandler/deleteSet.mjs'
+
+export const PERSIST_UPDATE = 0
+/**
+ * Write an update to an encoder.
+ *
+ * @param {Yjs} y A Yjs instance
+ * @param {BinaryEncoder} updateEncoder I.e. transaction.encodedStructs
+ */
+export function encodeUpdate (y, updateEncoder, encoder) {
+  encoder.writeVarUint(PERSIST_UPDATE)
+  encoder.writeBinaryEncoder(updateEncoder)
+}
+
+export const PERSIST_STRUCTS_DS = 1
+
+/**
+ * Write the current Yjs data model to an encoder.
+ *
+ * @param {Yjs} y A Yjs instance
+ * @param {BinaryEncoder} encoder An encoder to write to
+ */
+export function encodeStructsDS (y, encoder) {
+  encoder.writeVarUint(PERSIST_STRUCTS_DS)
+  writeStructs(y, encoder, new Map())
+  writeDeleteSet(y, encoder)
+}
+
+/**
+ * Feed the Yjs instance with the persisted state
+ * @param {Yjs} y A Yjs instance.
+ * @param {BinaryDecoder} decoder A Decoder instance that holds the file content.
+ */
+export function decodePersisted (y, decoder) {
+  y.transact(() => {
+    while (decoder.hasContent()) {
+      const contentType = decoder.readVarUint()
+      switch (contentType) {
+        case PERSIST_UPDATE:
+          integrateRemoteStructs(y, decoder)
+          break
+        case PERSIST_STRUCTS_DS:
+          integrateRemoteStructs(y, decoder)
+          readDeleteSet(y, decoder)
+          break
+      }
+    }
+  }, true)
+}
--- a/src/Store/DeleteStore.js
+++ b/src/Store/DeleteStore.js
@@ -1,125 +0,0 @@
-import Tree from '../Util/Tree.js'
-import ID from '../Util/ID.js'
-
-class DSNode {
-  constructor (id, len, gc) {
-    this._id = id
-    this.len = len
-    this.gc = gc
-  }
-  clone () {
-    return new DSNode(this._id, this.len, this.gc)
-  }
-}
-
-export default class DeleteStore extends Tree {
-  logTable () {
-    const deletes = []
-    this.iterate(null, null, function (n) {
-      deletes.push({
-        user: n._id.user,
-        clock: n._id.clock,
-        len: n.len,
-        gc: n.gc
-      })
-    })
-    console.table(deletes)
-  }
-  isDeleted (id) {
-    var n = this.findWithUpperBound(id)
-    return n !== null && n._id.user === id.user && id.clock < n._id.clock + n.len
-  }
-  /*
-   * Mark an operation as deleted. returns the deleted node
-   */
-  markDeleted (id, length) {
-    if (length == null) {
-      throw new Error('length must be defined')
-    }
-    var n = this.findWithUpperBound(id)
-    if (n != null && n._id.user === id.user) {
-      if (n._id.clock <= id.clock && id.clock <= n._id.clock + n.len) {
-        // id is in n's range
-        var diff = id.clock + length - (n._id.clock + n.len) // overlapping right
-        if (diff > 0) {
-          // id+length overlaps n
-          if (!n.gc) {
-            n.len += diff
-          } else {
-            diff = n._id.clock + n.len - id.clock // overlapping left (id till n.end)
-            if (diff < length) {
-              // a partial deletion
-              let nId = id.clone()
-              nId.clock += diff
-              n = new DSNode(nId, length - diff, false)
-              this.put(n)
-            } else {
-              // already gc'd
-              throw new Error(
-                'DS reached an inconsistent state. Please report this issue!'
-              )
-            }
-          }
-        } else {
-          // no overlapping, already deleted
-          return n
-        }
-      } else {
-        // cannot extend left (there is no left!)
-        n = new DSNode(id, length, false)
-        this.put(n) // TODO: you double-put !!
-      }
-    } else {
-      // cannot extend left
-      n = new DSNode(id, length, false)
-      this.put(n)
-    }
-    // can extend right?
-    var next = this.findNext(n._id)
-    if (
-      next != null &&
-      n._id.user === next._id.user &&
-      n._id.clock + n.len >= next._id.clock
-    ) {
-      diff = n._id.clock + n.len - next._id.clock // from next.start to n.end
-      while (diff >= 0) {
-        // n overlaps with next
-        if (next.gc) {
-          // gc is stronger, so reduce length of n
-          n.len -= diff
-          if (diff >= next.len) {
-            // delete the missing range after next
-            diff = diff - next.len // missing range after next
-            if (diff > 0) {
-              this.put(n) // unneccessary? TODO!
-              this.markDeleted(new ID(next._id.user, next._id.clock + next.len), diff)
-            }
-          }
-          break
-        } else {
-          // we can extend n with next
-          if (diff > next.len) {
-            // n is even longer than next
-            // get next.next, and try to extend it
-            var _next = this.findNext(next._id)
-            this.delete(next._id)
-            if (_next == null || n._id.user !== _next._id.user) {
-              break
-            } else {
-              next = _next
-              diff = n._id.clock + n.len - next._id.clock // from next.start to n.end
-              // continue!
-            }
-          } else {
-            // n just partially overlaps with next. extend n, delete next, and break this loop
-            n.len += next.len - diff
-            this.delete(next._id)
-            break
-          }
-        }
-      }
-    }
-    this.put(n)
-    return n
-  }
-}
--- a/src/Store/DeleteStore.mjs
+++ b/src/Store/DeleteStore.mjs
@@ -0,0 +1,90 @@
+
+import Tree from '../Util/Tree.mjs'
+import ID from '../Util/ID/ID.mjs'
+
+class DSNode {
+  constructor (id, len, gc) {
+    this._id = id
+    this.len = len
+    this.gc = gc
+  }
+  clone () {
+    return new DSNode(this._id, this.len, this.gc)
+  }
+}
+
+export default class DeleteStore extends Tree {
+  logTable () {
+    const deletes = []
+    this.iterate(null, null, function (n) {
+      deletes.push({
+        user: n._id.user,
+        clock: n._id.clock,
+        len: n.len,
+        gc: n.gc
+      })
+    })
+    console.table(deletes)
+  }
+  isDeleted (id) {
+    var n = this.findWithUpperBound(id)
+    return n !== null && n._id.user === id.user && id.clock < n._id.clock + n.len
+  }
+  mark (id, length, gc) {
+    if (length === 0) return
+    // Step 1. Unmark range
+    const leftD = this.findWithUpperBound(new ID(id.user, id.clock - 1))
+    // Resize left DSNode if necessary
+    if (leftD !== null && leftD._id.user === id.user) {
+      if (leftD._id.clock < id.clock && id.clock < leftD._id.clock + leftD.len) {
+        // node is overlapping. need to resize
+        if (id.clock + length < leftD._id.clock + leftD.len) {
+          // overlaps new mark range and some more
+          // create another DSNode to the right of new mark
+          this.put(new DSNode(new ID(id.user, id.clock + length), leftD._id.clock + leftD.len - id.clock - length, leftD.gc))
+        }
+        // resize left DSNode
+        leftD.len = id.clock - leftD._id.clock
+      } // Otherwise there is no overlapping
+    }
+    // Resize right DSNode if necessary
+    const upper = new ID(id.user, id.clock + length - 1)
+    const rightD = this.findWithUpperBound(upper)
+    if (rightD !== null && rightD._id.user === id.user) {
+      if (rightD._id.clock < id.clock + length && id.clock <= rightD._id.clock && id.clock + length < rightD._id.clock + rightD.len) { // we only consider the case where we resize the node
+        const d = id.clock + length - rightD._id.clock
+        rightD._id = new ID(rightD._id.user, rightD._id.clock + d)
+        rightD.len -= d
+      }
+    }
+    // Now we only have to delete all inner marks
+    const deleteNodeIds = []
+    this.iterate(id, upper, m => {
+      deleteNodeIds.push(m._id)
+    })
+    for (let i = deleteNodeIds.length - 1; i >= 0; i--) {
+      this.delete(deleteNodeIds[i])
+    }
+    let newMark = new DSNode(id, length, gc)
+    // Step 2. Check if we can extend left or right
+    if (leftD !== null && leftD._id.user === id.user && leftD._id.clock + leftD.len === id.clock && leftD.gc === gc) {
+      // We can extend left
+      leftD.len += length
+      newMark = leftD
+    }
+    const rightNext = this.find(new ID(id.user, id.clock + length))
+    if (rightNext !== null && rightNext._id.user === id.user && id.clock + length === rightNext._id.clock && gc === rightNext.gc) {
+      // We can merge newMark and rightNext
+      newMark.len += rightNext.len
+      this.delete(rightNext._id)
+    }
+    if (leftD !== newMark) {
+      // only put if we didn't extend left
+      this.put(newMark)
+    }
+  }
+  // TODO: exchange markDeleted for mark()
+  markDeleted (id, length) {
+    this.mark(id, length, false)
+  }
+}
--- a/src/Store/OperationStore.mjs
+++ b/src/Store/OperationStore.mjs
@@ -1,7 +1,8 @@
-import Tree from '../Util/Tree.js'
-import RootID from '../Util/RootID.js'
-import { getStruct } from '../Util/structReferences.js'
-import { logID } from '../MessageHandler/messageToString.js'
+import Tree from '../Util/Tree.mjs'
+import RootID from '../Util/ID/RootID.mjs'
+import { getStruct } from '../Util/structReferences.mjs'
+import { logID } from '../MessageHandler/messageToString.mjs'
+import GC from '../Struct/GC.mjs'

 export default class OperationStore extends Tree {
  constructor (y) {
@@ -11,17 +12,25 @@ export default class OperationStore extends Tree {
  logTable () {
    const items = []
    this.iterate(null, null, function (item) {
-      items.push({
-        id: logID(item),
-        origin: logID(item._origin === null ? null : item._origin._lastId),
-        left: logID(item._left === null ? null : item._left._lastId),
-        right: logID(item._right),
-        right_origin: logID(item._right_origin),
-        parent: logID(item._parent),
-        parentSub: item._parentSub,
-        deleted: item._deleted,
-        content: JSON.stringify(item._content)
-      })
+      if (item.constructor === GC) {
+        items.push({
+          id: logID(item),
+          content: item._length,
+          deleted: 'GC'
+        })
+      } else {
+        items.push({
+          id: logID(item),
+          origin: logID(item._origin === null ? null : item._origin._lastId),
+          left: logID(item._left === null ? null : item._left._lastId),
+          right: logID(item._right),
+          right_origin: logID(item._right_origin),
+          parent: logID(item._parent),
+          parentSub: item._parentSub,
+          deleted: item._deleted,
+          content: JSON.stringify(item._content)
+        })
+      }
    })
    console.table(items)
  }
--- a/src/Store/StateStore.mjs
+++ b/src/Store/StateStore.mjs
@@ -1,4 +1,4 @@
-import ID from '../Util/ID.js'
+import ID from '../Util/ID/ID.mjs'

 export default class StateStore {
  constructor (y) {
--- a/src/Struct/Delete.js
+++ b/src/Struct/Delete.js
@@ -1,84 +0,0 @@
-import { getReference } from '../Util/structReferences.js'
-import ID from '../Util/ID.js'
-import { logID } from '../MessageHandler/messageToString.js'
-
-/**
- * Delete all items in an ID-range
- * TODO: implement getItemCleanStartNode for better performance (only one lookup)
- */
-export function deleteItemRange (y, user, clock, range) {
-  const createDelete = y.connector._forwardAppliedStructs
-  let item = y.os.getItemCleanStart(new ID(user, clock))
-  if (item !== null) {
-    if (!item._deleted) {
-      item._splitAt(y, range)
-      item._delete(y, createDelete)
-    }
-    let itemLen = item._length
-    range -= itemLen
-    clock += itemLen
-    if (range > 0) {
-      let node = y.os.findNode(new ID(user, clock))
-      while (node !== null && range > 0 && node.val._id.equals(new ID(user, clock))) {
-        const nodeVal = node.val
-        if (!nodeVal._deleted) {
-          nodeVal._splitAt(y, range)
-          nodeVal._delete(y, createDelete)
-        }
-        const nodeLen = nodeVal._length
-        range -= nodeLen
-        clock += nodeLen
-        node = node.next()
-      }
-    }
-  }
-}
-
-/**
- * Delete is not a real struct. It will not be saved in OS
- */
-export default class Delete {
-  constructor () {
-    this._target = null
-    this._length = null
-  }
-  _fromBinary (y, decoder) {
-    // TODO: set target, and add it to missing if not found
-    // There is an edge case in p2p networks!
-    const targetID = decoder.readID()
-    this._targetID = targetID
-    this._length = decoder.readVarUint()
-    if (y.os.getItem(targetID) === null) {
-      return [targetID]
-    } else {
-      return []
-    }
-  }
-  _toBinary (encoder) {
-    encoder.writeUint8(getReference(this.constructor))
-    encoder.writeID(this._targetID)
-    encoder.writeVarUint(this._length)
-  }
-  /**
-   * - If created remotely (a remote user deleted something),
-   *   this Delete is applied to all structs in id-range.
-   * - If created lokally (e.g. when y-array deletes a range of elements),
-   *   this struct is broadcasted only (it is already executed)
-   */
-  _integrate (y, locallyCreated = false) {
-    if (!locallyCreated) {
-      // from remote
-      const id = this._targetID
-      deleteItemRange(y, id.user, id.clock, this._length)
-    } else {
-      // from local
-      y.connector.broadcastStruct(this)
-    }
-    if (y.persistence !== null) {
-      y.persistence.saveOperations(this)
-    }
-  }
-  _logString () {
-    return `Delete - target: ${logID(this._targetID)}, len: ${this._length}`
-  }
-}
--- a/src/Struct/Delete.mjs
+++ b/src/Struct/Delete.mjs
@@ -0,0 +1,124 @@
+import { getStructReference } from '../Util/structReferences.mjs'
+import ID from '../Util/ID/ID.mjs'
+import { logID } from '../MessageHandler/messageToString.mjs'
+import { writeStructToTransaction } from '../Transaction.mjs'
+
+/**
+ * @private
+ * Delete all items in an ID-range
+ * TODO: implement getItemCleanStartNode for better performance (only one lookup)
+ */
+export function deleteItemRange (y, user, clock, range, gcChildren) {
+  const createDelete = y.connector !== null && y.connector._forwardAppliedStructs
+  let item = y.os.getItemCleanStart(new ID(user, clock))
+  if (item !== null) {
+    if (!item._deleted) {
+      item._splitAt(y, range)
+      item._delete(y, createDelete, true)
+    }
+    let itemLen = item._length
+    range -= itemLen
+    clock += itemLen
+    if (range > 0) {
+      let node = y.os.findNode(new ID(user, clock))
+      while (node !== null && node.val !== null && range > 0 && node.val._id.equals(new ID(user, clock))) {
+        const nodeVal = node.val
+        if (!nodeVal._deleted) {
+          nodeVal._splitAt(y, range)
+          nodeVal._delete(y, createDelete, gcChildren)
+        }
+        const nodeLen = nodeVal._length
+        range -= nodeLen
+        clock += nodeLen
+        node = node.next()
+      }
+    }
+  }
+}
+
+/**
+ * @private
+ * A Delete change is not a real Item, but it provides the same interface as an
+ * Item. The only difference is that it will not be saved in the ItemStore
+ * (OperationStore), but instead it is safed in the DeleteStore.
+ */
+export default class Delete {
+  constructor () {
+    this._target = null
+    this._length = null
+  }
+
+  /**
+   * @private
+   * Read the next Item in a Decoder and fill this Item with the read data.
+   *
+   * This is called when data is received from a remote peer.
+   *
+   * @param {Y} y The Yjs instance that this Item belongs to.
+   * @param {BinaryDecoder} decoder The decoder object to read data from.
+   */
+  _fromBinary (y, decoder) {
+    // TODO: set target, and add it to missing if not found
+    // There is an edge case in p2p networks!
+    const targetID = decoder.readID()
+    this._targetID = targetID
+    this._length = decoder.readVarUint()
+    if (y.os.getItem(targetID) === null) {
+      return [targetID]
+    } else {
+      return []
+    }
+  }
+
+  /**
+   * @private
+   * Transform the properties of this type to binary and write it to an
+   * BinaryEncoder.
+   *
+   * This is called when this Item is sent to a remote peer.
+   *
+   * @param {BinaryEncoder} encoder The encoder to write data to.
+   */
+  _toBinary (encoder) {
+    encoder.writeUint8(getStructReference(this.constructor))
+    encoder.writeID(this._targetID)
+    encoder.writeVarUint(this._length)
+  }
+
+  /**
+   * @private
+   * Integrates this Item into the shared structure.
+   *
+   * This method actually applies the change to the Yjs instance. In the case of
+   * Delete it marks the delete target as deleted.
+   *
+   * * If created remotely (a remote user deleted something),
+   *   this Delete is applied to all structs in id-range.
+   * * If created lokally (e.g. when y-array deletes a range of elements),
+   *   this struct is broadcasted only (it is already executed)
+   */
+  _integrate (y, locallyCreated = false) {
+    if (!locallyCreated) {
+      // from remote
+      const id = this._targetID
+      deleteItemRange(y, id.user, id.clock, this._length, false)
+    } else if (y.connector !== null) {
+      // from local
+      y.connector.broadcastStruct(this)
+    }
+    if (y.persistence !== null) {
+      y.persistence.saveStruct(y, this)
+    }
+    writeStructToTransaction(y._transaction, this)
+  }
+
+  /**
+   * Transform this YXml Type to a readable format.
+   * Useful for logging as all Items and Delete implement this method.
+   *
+   * @private
+   */
+  _logString () {
+    return `Delete - target: ${logID(this._targetID)}, len: ${this._length}`
+  }
+}
--- a/src/Struct/GC.mjs
+++ b/src/Struct/GC.mjs
@@ -0,0 +1,96 @@
+import { getStructReference } from '../Util/structReferences.mjs'
+import { RootFakeUserID } from '../Util/ID/RootID.mjs'
+import ID from '../Util/ID/ID.mjs'
+import { writeStructToTransaction } from '../Transaction.mjs'
+
+// TODO should have the same base class as Item
+export default class GC {
+  constructor () {
+    this._id = null
+    this._length = 0
+  }
+
+  get _deleted () {
+    return true
+  }
+
+  _integrate (y) {
+    const id = this._id
+    const userState = y.ss.getState(id.user)
+    if (id.clock === userState) {
+      y.ss.setState(id.user, id.clock + this._length)
+    }
+    y.ds.mark(this._id, this._length, true)
+    let n = y.os.put(this)
+    const prev = n.prev().val
+    if (prev !== null && prev.constructor === GC && prev._id.user === n.val._id.user && prev._id.clock + prev._length === n.val._id.clock) {
+      // TODO: do merging for all items!
+      prev._length += n.val._length
+      y.os.delete(n.val._id)
+      n = prev
+    }
+    if (n.val) {
+      n = n.val
+    }
+    const next = y.os.findNext(n._id)
+    if (next !== null && next.constructor === GC && next._id.user === n._id.user && next._id.clock === n._id.clock + n._length) {
+      n._length += next._length
+      y.os.delete(next._id)
+    }
+    if (id.user !== RootFakeUserID) {
+      if (y.connector !== null && (y.connector._forwardAppliedStructs || id.user === y.userID)) {
+        y.connector.broadcastStruct(this)
+      }
+      if (y.persistence !== null) {
+        y.persistence.saveStruct(y, this)
+      }
+      writeStructToTransaction(y._transaction, this)
+    }
+  }
+
+  /**
+   * Transform the properties of this type to binary and write it to an
+   * BinaryEncoder.
+   *
+   * This is called when this Item is sent to a remote peer.
+   *
+   * @param {BinaryEncoder} encoder The encoder to write data to.
+   * @private
+   */
+  _toBinary (encoder) {
+    encoder.writeUint8(getStructReference(this.constructor))
+    encoder.writeID(this._id)
+    encoder.writeVarUint(this._length)
+  }
+
+  /**
+   * Read the next Item in a Decoder and fill this Item with the read data.
+   *
+   * This is called when data is received from a remote peer.
+   *
+   * @param {Y} y The Yjs instance that this Item belongs to.
+   * @param {BinaryDecoder} decoder The decoder object to read data from.
+   * @private
+   */
+  _fromBinary (y, decoder) {
+    const id = decoder.readID()
+    this._id = id
+    this._length = decoder.readVarUint()
+    const missing = []
+    if (y.ss.getState(id.user) < id.clock) {
+      missing.push(new ID(id.user, id.clock - 1))
+    }
+    return missing
+  }
+
+  _splitAt () {
+    return this
+  }
+
+  _clonePartial (diff) {
+    const gc = new GC()
+    gc._id = new ID(this._id.user, this._id.clock + diff)
+    gc._length = this._length - diff
+    return gc
+  }
+}
--- a/src/Struct/Item.mjs
+++ b/src/Struct/Item.mjs
@@ -1,15 +1,17 @@
-import { getReference } from '../Util/structReferences.js'
-import ID from '../Util/ID.js'
-import { RootFakeUserID } from '../Util/RootID.js'
-import Delete from './Delete.js'
-import { transactionTypeChanged } from '../Transaction.js'
+import { getStructReference } from '../Util/structReferences.mjs'
+import ID from '../Util/ID/ID.mjs'
+import { default as RootID, RootFakeUserID } from '../Util/ID/RootID.mjs'
+import Delete from './Delete.mjs'
+import { transactionTypeChanged, writeStructToTransaction } from '../Transaction.mjs'
+import GC from './GC.mjs'

 /**
- * Helper utility to split an Item (see _splitAt)
- * - copy all properties from a to b
- * - connect a to b
+ * @private
+ * Helper utility to split an Item (see {@link Item#_splitAt})
+ * - copies all properties from a to b
+ * - connects a to b
 * - assigns the correct _id
- * - save b to os
+ * - saves b to os
 */
 export function splitHelper (y, a, b, diff) {
  const aID = a._id
@@ -39,46 +41,166 @@ export function splitHelper (y, a, b, diff) {
    o = o._right
  }
  y.os.put(b)
+  if (y._transaction.newTypes.has(a)) {
+    y._transaction.newTypes.add(b)
+  } else if (y._transaction.deletedStructs.has(a)) {
+    y._transaction.deletedStructs.add(b)
+  }
 }

+/**
+ * Abstract class that represents any content.
+ */
 export default class Item {
  constructor () {
+    /**
+     * The uniqe identifier of this type.
+     * @type {ID}
+     */
    this._id = null
+    /**
+     * The item that was originally to the left of this item.
+     * @type {Item}
+     */
    this._origin = null
+    /**
+     * The item that is currently to the left of this item.
+     * @type {Item}
+     */
    this._left = null
+    /**
+     * The item that is currently to the right of this item.
+     * @type {Item}
+     */
    this._right = null
+    /**
+     * The item that was originally to the right of this item.
+     * @type {Item}
+     */
    this._right_origin = null
+    /**
+     * The parent type.
+     * @type {Y|YType}
+     */
    this._parent = null
+    /**
+     * If the parent refers to this item with some kind of key (e.g. YMap, the
+     * key is specified here. The key is then used to refer to the list in which
+     * to insert this item. If `parentSub = null` type._start is the list in
+     * which to insert to. Otherwise it is `parent._start`.
+     * @type {String}
+     */
    this._parentSub = null
+    /**
+     * Whether this item was deleted or not.
+     * @type {Boolean}
+     */
    this._deleted = false
+    /**
+     * If this type's effect is reundone this type refers to the type that undid
+     * this operation.
+     * @type {Item}
+     */
+    this._redone = null
  }
+
  /**
-   * Copy the effect of struct
+   * Creates an Item with the same effect as this Item (without position effect)
+   *
+   * @private
   */
  _copy () {
-    let struct = new this.constructor()
-    struct._origin = this._left
-    struct._left = this._left
-    struct._right = this
-    struct._right_origin = this
-    struct._parent = this._parent
+    return new this.constructor()
+  }
+
+  /**
+   * Redoes the effect of this operation.
+   *
+   * @param {Y} y The Yjs instance.
+   *
+   * @private
+   */
+  _redo (y) {
+    if (this._redone !== null) {
+      return this._redone
+    }
+    let struct = this._copy()
+    let left = this._left
+    let right = this
+    let parent = this._parent
+    // make sure that parent is redone
+    if (parent._deleted === true && parent._redone === null) {
+      parent._redo(y)
+    }
+    if (parent._redone !== null) {
+      parent = parent._redone
+      // find next cloned items
+      while (left !== null) {
+        if (left._redone !== null && left._redone._parent === parent) {
+          left = left._redone
+          break
+        }
+        left = left._left
+      }
+      while (right !== null) {
+        if (right._redone !== null && right._redone._parent === parent) {
+          right = right._redone
+        }
+        right = right._right
+      }
+    }
+    struct._origin = left
+    struct._left = left
+    struct._right = right
+    struct._right_origin = right
+    struct._parent = parent
    struct._parentSub = this._parentSub
+    struct._integrate(y)
+    this._redone = struct
    return struct
  }
+
+  /**
+   * Computes the last content address of this Item.
+   *
+   * @private
+   */
  get _lastId () {
    return new ID(this._id.user, this._id.clock + this._length - 1)
  }
+
+  /**
+   * Computes the length of this Item.
+   *
+   * @private
+   */
  get _length () {
    return 1
  }
+
  /**
-   * Splits this struct so that another struct can be inserted in-between.
+   * 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
+   *
+   * @private
+   */
+  get _countable () {
+    return true
+  }
+
+  /**
+   * Splits this Item so that another Items can be inserted in-between.
   * This must be overwritten if _length > 1
   * Returns right part after split
-   * - diff === 0 => this
-   * - diff === length => this._right
-   * - otherwise => split _content and return right part of split
-   * (see ItemJSON/ItemString for implementation)
+   * * diff === 0 => this
+   * * diff === length => this._right
+   * * otherwise => split _content and return right part of split
+   * (see {@link ItemJSON}/{@link ItemString} for implementation)
+   *
+   * @private
   */
  _splitAt (y, diff) {
    if (diff === 0) {
@@ -86,34 +208,74 @@ export default class Item {
    }
    return this._right
  }
+
+  /**
+   * Mark this Item as deleted.
+   *
+   * @param {Y} y The Yjs instance
+   * @param {boolean} createDelete Whether to propagate a message that this
+   *                               Type was deleted.
+   *
+   * @private
+   */
  _delete (y, createDelete = true) {
-    this._deleted = true
-    y.ds.markDeleted(this._id, this._length)
-    if (createDelete) {
+    if (!this._deleted) {
+      this._deleted = true
+      y.ds.mark(this._id, this._length, false)
      let del = new Delete()
      del._targetID = this._id
      del._length = this._length
-      del._integrate(y, true)
+      if (createDelete) {
+        // broadcast and persists Delete
+        del._integrate(y, true)
+      } else if (y.persistence !== null) {
+        // only persist Delete
+        y.persistence.saveStruct(y, del)
+      }
+      transactionTypeChanged(y, this._parent, this._parentSub)
+      y._transaction.deletedStructs.add(this)
    }
-    transactionTypeChanged(y, this._parent, this._parentSub)
-    y._transaction.deletedStructs.add(this)
  }
+
+  _gcChildren (y) {}
+
+  _gc (y) {
+    const gc = new GC()
+    gc._id = this._id
+    gc._length = this._length
+    y.os.delete(this._id)
+    gc._integrate(y)
+  }
+
  /**
-   * This is called right before this struct receives any children.
+   * This is called right before this Item receives any children.
   * It can be overwritten to apply pending changes before applying remote changes
+   *
+   * @private
   */
  _beforeChange () {
    // nop
  }
-  /*
-   * - Integrate the struct so that other types/structs can see it
-   * - Add this struct to y.os
-   * - Check if this is struct deleted
+
+  /**
+   * Integrates this Item into the shared structure.
+   *
+   * This method actually applies the change to the Yjs instance. In case of
+   * Item it connects _left and _right to this Item and calls the
+   * {@link Item#beforeChange} method.
+   *
+   * * Integrate the struct so that other types/structs can see it
+   * * Add this struct to y.os
+   * * Check if this is struct deleted
+   *
+   * @private
   */
  _integrate (y) {
+    y._transaction.newTypes.add(this)
    const parent = this._parent
    const selfID = this._id
-    const userState = selfID === null ? 0 : y.ss.getState(selfID.user)
+    const user = selfID === null ? y.userID : selfID.user
+    const userState = y.ss.getState(user)
    if (selfID === null) {
      this._id = y.ss.getNextID(this._length)
    } else if (selfID.user === RootFakeUserID) {
@@ -132,6 +294,7 @@ export default class Item {
      // or this types is new
      this._parent._beforeChange()
    }
+
    /*
    # $this has to find a unique position between origin and the next known character
    # case 1: $origin equals $o.origin: the $creator parameter decides if left or right
@@ -216,16 +379,28 @@ export default class Item {
    y.os.put(this)
    transactionTypeChanged(y, parent, parentSub)
    if (this._id.user !== RootFakeUserID) {
-      if (y.connector._forwardAppliedStructs || this._id.user === y.userID) {
+      if (y.connector !== null && (y.connector._forwardAppliedStructs || this._id.user === y.userID)) {
        y.connector.broadcastStruct(this)
      }
      if (y.persistence !== null) {
-        y.persistence.saveOperations(this)
+        y.persistence.saveStruct(y, this)
      }
+      writeStructToTransaction(y._transaction, this)
    }
  }
+
+  /**
+   * Transform the properties of this type to binary and write it to an
+   * BinaryEncoder.
+   *
+   * This is called when this Item is sent to a remote peer.
+   *
+   * @param {BinaryEncoder} encoder The encoder to write data to.
+   *
+   * @private
+   */
  _toBinary (encoder) {
-    encoder.writeUint8(getReference(this.constructor))
+    encoder.writeUint8(getStructReference(this.constructor))
    let info = 0
    if (this._origin !== null) {
      info += 0b1 // origin is defined
@@ -264,6 +439,17 @@ export default class Item {
      encoder.writeVarString(JSON.stringify(this._parentSub))
    }
  }
+
+  /**
+   * Read the next Item in a Decoder and fill this Item with the read data.
+   *
+   * This is called when data is received from a remote peer.
+   *
+   * @param {Y} y The Yjs instance that this Item belongs to.
+   * @param {BinaryDecoder} decoder The decoder object to read data from.
+   *
+   * @private
+   */
  _fromBinary (y, decoder) {
    let missing = []
    const info = decoder.readUint8()
@@ -301,7 +487,12 @@ export default class Item {
      const parentID = decoder.readID()
      // parent does not change, so we don't have to search for it again
      if (this._parent === null) {
-        const parent = y.os.get(parentID)
+        let parent
+        if (parentID.constructor === RootID) {
+          parent = y.os.get(parentID)
+        } else {
+          parent = y.os.getItem(parentID)
+        }
        if (parent === null) {
          missing.push(parentID)
        } else {
@@ -310,9 +501,19 @@ export default class Item {
      }
    } else if (this._parent === null) {
      if (this._origin !== null) {
-        this._parent = this._origin._parent
+        if (this._origin.constructor === GC) {
+          // if origin is a gc, set parent also gc'd
+          this._parent = this._origin
+        } else {
+          this._parent = this._origin._parent
+        }
      } else if (this._right_origin !== null) {
-        this._parent = this._right_origin._parent
+        // if origin is a gc, set parent also gc'd
+        if (this._right_origin.constructor === GC) {
+          this._parent = this._right_origin
+        } else {
+          this._parent = this._right_origin._parent
+        }
      }
    }
    if (info & 0b1000) {
--- a/src/Struct/ItemEmbed.mjs
+++ b/src/Struct/ItemEmbed.mjs
@@ -0,0 +1,35 @@
+import Item from './Item.mjs'
+import { logItemHelper } from '../MessageHandler/messageToString.mjs'
+
+export default class ItemEmbed extends Item {
+  constructor () {
+    super()
+    this.embed = null
+  }
+  _copy (undeleteChildren, copyPosition) {
+    let struct = super._copy(undeleteChildren, copyPosition)
+    struct.embed = this.embed
+    return struct
+  }
+  get _length () {
+    return 1
+  }
+  _fromBinary (y, decoder) {
+    const missing = super._fromBinary(y, decoder)
+    this.embed = JSON.parse(decoder.readVarString())
+    return missing
+  }
+  _toBinary (encoder) {
+    super._toBinary(encoder)
+    encoder.writeVarString(JSON.stringify(this.embed))
+  }
+  /**
+   * Transform this YXml Type to a readable format.
+   * Useful for logging as all Items and Delete implement this method.
+   *
+   * @private
+   */
+  _logString () {
+    return logItemHelper('ItemEmbed', this, `embed:${JSON.stringify(this.embed)}`)
+  }
+}
--- a/src/Struct/ItemFormat.mjs
+++ b/src/Struct/ItemFormat.mjs
@@ -0,0 +1,42 @@
+import Item from './Item.mjs'
+import { logItemHelper } from '../MessageHandler/messageToString.mjs'
+
+export default class ItemFormat extends Item {
+  constructor () {
+    super()
+    this.key = null
+    this.value = null
+  }
+  _copy (undeleteChildren, copyPosition) {
+    let struct = super._copy(undeleteChildren, copyPosition)
+    struct.key = this.key
+    struct.value = this.value
+    return struct
+  }
+  get _length () {
+    return 1
+  }
+  get _countable () {
+    return false
+  }
+  _fromBinary (y, decoder) {
+    const missing = super._fromBinary(y, decoder)
+    this.key = decoder.readVarString()
+    this.value = JSON.parse(decoder.readVarString())
+    return missing
+  }
+  _toBinary (encoder) {
+    super._toBinary(encoder)
+    encoder.writeVarString(this.key)
+    encoder.writeVarString(JSON.stringify(this.value))
+  }
+  /**
+   * Transform this YXml Type to a readable format.
+   * Useful for logging as all Items and Delete implement this method.
+   *
+   * @private
+   */
+  _logString () {
+    return logItemHelper('ItemFormat', this, `key:${JSON.stringify(this.key)},value:${JSON.stringify(this.value)}`)
+  }
+}
--- a/src/Struct/ItemJSON.mjs
+++ b/src/Struct/ItemJSON.mjs
@@ -1,5 +1,5 @@
-import { splitHelper, default as Item } from './Item.js'
-import { logID } from '../MessageHandler/messageToString.js'
+import Item, { splitHelper } from './Item.mjs'
+import { logItemHelper } from '../MessageHandler/messageToString.mjs'

 export default class ItemJSON extends Item {
  constructor () {
@@ -45,10 +45,14 @@ export default class ItemJSON extends Item {
      encoder.writeVarString(encoded)
    }
  }
+  /**
+   * Transform this YXml Type to a readable format.
+   * Useful for logging as all Items and Delete implement this method.
+   *
+   * @private
+   */
  _logString () {
-    const left = this._left !== null ? this._left._lastId : null
-    const origin = this._origin !== null ? this._origin._lastId : null
-    return `ItemJSON(id:${logID(this._id)},content:${JSON.stringify(this._content)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
+    return logItemHelper('ItemJSON', this, `content:${JSON.stringify(this._content)}`)
  }
  _splitAt (y, diff) {
    if (diff === 0) {
--- a/src/Struct/ItemString.mjs
+++ b/src/Struct/ItemString.mjs
@@ -1,5 +1,5 @@
-import { splitHelper, default as Item } from './Item.js'
-import { logID } from '../MessageHandler/messageToString.js'
+import Item, { splitHelper } from './Item.mjs'
+import { logItemHelper } from '../MessageHandler/messageToString.mjs'

 export default class ItemString extends Item {
  constructor () {
@@ -23,10 +23,14 @@ export default class ItemString extends Item {
    super._toBinary(encoder)
    encoder.writeVarString(this._content)
  }
+  /**
+   * Transform this YXml Type to a readable format.
+   * Useful for logging as all Items and Delete implement this method.
+   *
+   * @private
+   */
  _logString () {
-    const left = this._left !== null ? this._left._lastId : null
-    const origin = this._origin !== null ? this._origin._lastId : null
-    return `ItemJSON(id:${logID(this._id)},content:${JSON.stringify(this._content)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
+    return logItemHelper('ItemString', this, `content:"${this._content}"`)
  }
  _splitAt (y, diff) {
    if (diff === 0) {
--- a/src/Struct/Type.mjs
+++ b/src/Struct/Type.mjs
@@ -1,6 +1,6 @@
-import Item from './Item.js'
-import EventHandler from '../Util/EventHandler.js'
-import ID from '../Util/ID.js'
+import Item from './Item.mjs'
+import EventHandler from '../Util/EventHandler.mjs'
+import ID from '../Util/ID/ID.mjs'

 // restructure children as if they were inserted one after another
 function integrateChildren (y, start) {
@@ -30,6 +30,17 @@ export function getListItemIDByPosition (type, i) {
  }
 }

+function gcChildren (y, item) {
+  while (item !== null) {
+    item._delete(y, false, true)
+    item._gc(y)
+    item = item._right
+  }
+}
+
+/**
+ * Abstract Yjs Type class
+ */
 export default class Type extends Item {
  constructor () {
    super()
@@ -39,32 +50,52 @@ export default class Type extends Item {
    this._eventHandler = new EventHandler()
    this._deepEventHandler = new EventHandler()
  }
+
+  /**
+   * Compute the path from this type to the specified target.
+   *
+   * @example
+   * It should be accessible via `this.get(result[0]).get(result[1])..`
+   * const path = type.getPathTo(child)
+   * // assuming `type instanceof YArray`
+   * console.log(path) // might look like => [2, 'key1']
+   * child === type.get(path[0]).get(path[1])
+   *
+   * @param {YType} type Type target
+   * @return {Array<string>} Path to the target
+   */
  getPathTo (type) {
    if (type === this) {
      return []
    }
    const path = []
    const y = this._y
-    while (type._parent !== this && this._parent !== y) {
+    while (type !== this && type !== y) {
      let parent = type._parent
      if (type._parentSub !== null) {
-        path.push(type._parentSub)
+        path.unshift(type._parentSub)
      } else {
        // parent is array-ish
        for (let [i, child] of parent) {
          if (child === type) {
-            path.push(i)
+            path.unshift(i)
            break
          }
        }
      }
      type = parent
    }
-    if (this._parent !== this) {
+    if (type !== this) {
      throw new Error('The type is not a child of this node')
    }
    return path
  }
+
+  /**
+   * @private
+   * Call event listeners with an event. This will also add an event to all
+   * parents (for `.observeDeep` handlers).
+   */
  _callEventHandler (transaction, event) {
    const changedParentTypes = transaction.changedParentTypes
    this._eventHandler.callEventListeners(transaction, event)
@@ -79,39 +110,14 @@ export default class Type extends Item {
      type = type._parent
    }
  }
-  _copy (undeleteChildren) {
-    let copy = super._copy()
-    let map = new Map()
-    copy._map = map
-    for (let [key, value] of this._map) {
-      if (undeleteChildren.has(value) || !value.deleted) {
-        let _item = value._copy(undeleteChildren)
-        _item._parent = copy
-        map.set(key, value._copy(undeleteChildren))
-      }
-    }
-    let prevUndeleted = null
-    copy._start = null
-    let item = this._start
-    while (item !== null) {
-      if (undeleteChildren.has(item) || !item.deleted) {
-        let _item = item._copy(undeleteChildren)
-        _item._left = prevUndeleted
-        _item._origin = prevUndeleted
-        _item._right = null
-        _item._right_origin = null
-        _item._parent = copy
-        if (prevUndeleted === null) {
-          copy._start = _item
-        } else {
-          prevUndeleted._right = _item
-        }
-        prevUndeleted = _item
-      }
-      item = item._right
-    }
-    return copy
-  }
+
+  /**
+   * @private
+   * Helper method to transact if the y instance is available.
+   *
+   * TODO: Currently event handlers are not thrown when a type is not registered
+   *       with a Yjs instance.
+   */
  _transact (f) {
    const y = this._y
    if (y !== null) {
@@ -120,20 +126,54 @@ export default class Type extends Item {
      f(y)
    }
  }
+
+  /**
+   * Observe all events that are created on this type.
+   *
+   * @param {Function} f Observer function
+   */
  observe (f) {
    this._eventHandler.addEventListener(f)
  }
+
+  /**
+   * Observe all events that are created by this type and its children.
+   *
+   * @param {Function} f Observer function
+   */
  observeDeep (f) {
    this._deepEventHandler.addEventListener(f)
  }
+
+  /**
+   * Unregister an observer function.
+   *
+   * @param {Function} f Observer function
+   */
  unobserve (f) {
    this._eventHandler.removeEventListener(f)
  }
+
+  /**
+   * Unregister an observer function.
+   *
+   * @param {Function} f Observer function
+   */
  unobserveDeep (f) {
    this._deepEventHandler.removeEventListener(f)
  }
+
+  /**
+   * @private
+   * Integrate this type into the Yjs instance.
+   *
+   * * Save this struct in the os
+   * * This type is sent to other client
+   * * Observer functions are fired
+   *
+   * @param {Y} y The Yjs instance
+   */
  _integrate (y) {
-    y._transaction.newTypes.add(this)
    super._integrate(y)
    this._y = y
    // when integrating children we must make sure to
@@ -151,22 +191,53 @@ export default class Type extends Item {
      integrateChildren(y, t)
    }
  }
-  _delete (y, createDelete) {
-    super._delete(y, createDelete)
+
+  _gcChildren (y) {
+    gcChildren(y, this._start)
+    this._start = null
+    this._map.forEach(item => {
+      gcChildren(y, item)
+    })
+    this._map = new Map()
+  }
+
+  _gc (y) {
+    this._gcChildren(y)
+    super._gc(y)
+  }
+
+  /**
+   * @private
+   * Mark this Item as deleted.
+   *
+   * @param {Y} y The Yjs instance
+   * @param {boolean} createDelete Whether to propagate a message that this
+   *                               Type was deleted.
+   * @param {boolean} [gcChildren=y._hasUndoManager===false] Whether to garbage
+   *                                         collect the children of this type.
+   */
+  _delete (y, createDelete, gcChildren) {
+    if (gcChildren === undefined || !y.gcEnabled) {
+      gcChildren = y._hasUndoManager === false && y.gcEnabled
+    }
+    super._delete(y, createDelete, gcChildren)
    y._transaction.changedTypes.delete(this)
    // delete map types
    for (let value of this._map.values()) {
      if (value instanceof Item && !value._deleted) {
-        value._delete(y, false)
+        value._delete(y, false, gcChildren)
      }
    }
    // delete array types
    let t = this._start
    while (t !== null) {
      if (!t._deleted) {
-        t._delete(y, false)
+        t._delete(y, false, gcChildren)
      }
      t = t._right
    }
+    if (gcChildren) {
+      this._gcChildren(y)
+    }
  }
 }
--- a/src/Transaction.js
+++ b/src/Transaction.js
@@ -1,27 +0,0 @@
-
-export default class Transaction {
-  constructor (y) {
-    this.y = y
-    // types added during transaction
-    this.newTypes = new Set()
-    // changed types (does not include new types)
-    // maps from type to parentSubs (item._parentSub = null for array elements)
-    this.changedTypes = new Map()
-    this.deletedStructs = new Set()
-    this.beforeState = new Map()
-    this.changedParentTypes = new Map()
-  }
-}
-
-export function transactionTypeChanged (y, type, sub) {
-  if (type !== y && !type._deleted && !y._transaction.newTypes.has(type)) {
-    const changedTypes = y._transaction.changedTypes
-    let subs = changedTypes.get(type)
-    if (subs === undefined) {
-      // create if it doesn't exist yet
-      subs = new Set()
-      changedTypes.set(type, subs)
-    }
-    subs.add(sub)
-  }
-}
--- a/src/Transaction.mjs
+++ b/src/Transaction.mjs
@@ -0,0 +1,91 @@
+import BinaryEncoder from './Util/Binary/Encoder.mjs'
+
+/**
+ * A transaction is created for every change on the Yjs model. It is possible
+ * to bundle changes on the Yjs model in a single transaction to
+ * minimize the number on messages sent and the number of observer calls.
+ * If possible the user of this library should bundle as many changes as
+ * possible. Here is an example to illustrate the advantages of bundling:
+ *
+ * @example
+ * const map = y.define('map', YMap)
+ * // Log content when change is triggered
+ * map.observe(function () {
+ *   console.log('change triggered')
+ * })
+ * // Each change on the map type triggers a log message:
+ * map.set('a', 0) // => "change triggered"
+ * map.set('b', 0) // => "change triggered"
+ * // When put in a transaction, it will trigger the log after the transaction:
+ * y.transact(function () {
+ *   map.set('a', 1)
+ *   map.set('b', 1)
+ * }) // => "change triggered"
+ *
+ */
+export default class Transaction {
+  constructor (y) {
+    /**
+     * @type {Y} The Yjs instance.
+     */
+    this.y = y
+    /**
+     * All new types that are added during a transaction.
+     * @type {Set<Item>}
+     */
+    this.newTypes = new Set()
+    /**
+     * All types that were directly modified (property added or child
+     * inserted/deleted). New types are not included in this Set.
+     * Maps from type to parentSubs (`item._parentSub = null` for YArray)
+     * @type {Set<YType,String>}
+     */
+    this.changedTypes = new Map()
+    // TODO: rename deletedTypes
+    /**
+     * Set of all deleted Types and Structs.
+     * @type {Set<Item>}
+     */
+    this.deletedStructs = new Set()
+    /**
+     * Saves the old state set of the Yjs instance. If a state was modified,
+     * the original value is saved here.
+     * @type {Map<Number,Number>}
+     */
+    this.beforeState = new Map()
+    /**
+     * Stores the events for the types that observe also child elements.
+     * It is mainly used by `observeDeep`.
+     * @type {Map<YType,Array<YEvent>>}
+     */
+    this.changedParentTypes = new Map()
+    this.encodedStructsLen = 0
+    this._encodedStructs = new BinaryEncoder()
+    this._encodedStructs.writeUint32(0)
+  }
+  get encodedStructs () {
+    this._encodedStructs.setUint32(0, this.encodedStructsLen)
+    return this._encodedStructs
+  }
+}
+
+export function writeStructToTransaction (transaction, struct) {
+  transaction.encodedStructsLen++
+  struct._toBinary(transaction._encodedStructs)
+}
+
+/**
+ * @private
+ */
+export function transactionTypeChanged (y, type, sub) {
+  if (type !== y && !type._deleted && !y._transaction.newTypes.has(type)) {
+    const changedTypes = y._transaction.changedTypes
+    let subs = changedTypes.get(type)
+    if (subs === undefined) {
+      // create if it doesn't exist yet
+      subs = new Set()
+      changedTypes.set(type, subs)
+    }
+    subs.add(sub)
+  }
+}
--- a/src/Type/YArray.js
+++ b/src/Type/YArray.js
@@ -1,222 +0,0 @@
-import Type from '../Struct/Type.js'
-import ItemJSON from '../Struct/ItemJSON.js'
-import ItemString from '../Struct/ItemString.js'
-import { logID } from '../MessageHandler/messageToString.js'
-import YEvent from '../Util/YEvent.js'
-
-class YArrayEvent extends YEvent {
-  constructor (yarray, remote) {
-    super(yarray)
-    this.remote = remote
-  }
-}
-
-export default class YArray extends Type {
-  _callObserver (transaction, parentSubs, remote) {
-    this._callEventHandler(transaction, new YArrayEvent(this, remote))
-  }
-  get (pos) {
-    let n = this._start
-    while (n !== null) {
-      if (!n._deleted) {
-        if (pos < n._length) {
-          if (n.constructor === ItemJSON || n.constructor === ItemString) {
-            return n._content[pos]
-          } else {
-            return n
-          }
-        }
-        pos -= n._length
-      }
-      n = n._right
-    }
-  }
-  toArray () {
-    return this.map(c => c)
-  }
-  toJSON () {
-    return this.map(c => {
-      if (c instanceof Type) {
-        if (c.toJSON !== null) {
-          return c.toJSON()
-        } else {
-          return c.toString()
-        }
-      }
-      return c
-    })
-  }
-  map (f) {
-    const res = []
-    this.forEach((c, i) => {
-      res.push(f(c, i, this))
-    })
-    return res
-  }
-  forEach (f) {
-    let pos = 0
-    let n = this._start
-    while (n !== null) {
-      if (!n._deleted) {
-        if (n instanceof Type) {
-          f(n, pos++, this)
-        } else {
-          const content = n._content
-          const contentLen = content.length
-          for (let i = 0; i < contentLen; i++) {
-            pos++
-            f(content[i], pos, this)
-          }
-        }
-      }
-      n = n._right
-    }
-  }
-  get length () {
-    let length = 0
-    let n = this._start
-    while (n !== null) {
-      if (!n._deleted) {
-        length += n._length
-      }
-      n = n._right
-    }
-    return length
-  }
-  [Symbol.iterator] () {
-    return {
-      next: function () {
-        while (this._item !== null && (this._item._deleted || this._item._length <= this._itemElement)) {
-          // item is deleted or itemElement does not exist (is deleted)
-          this._item = this._item._right
-          this._itemElement = 0
-        }
-        if (this._item === null) {
-          return {
-            done: true
-          }
-        }
-        let content
-        if (this._item instanceof Type) {
-          content = this._item
-        } else {
-          content = this._item._content[this._itemElement++]
-        }
-        return {
-          value: [this._count, content],
-          done: false
-        }
-      },
-      _item: this._start,
-      _itemElement: 0,
-      _count: 0
-    }
-  }
-  delete (pos, length = 1) {
-    this._y.transact(() => {
-      let item = this._start
-      let count = 0
-      while (item !== null && length > 0) {
-        if (!item._deleted) {
-          if (count <= pos && pos < count + item._length) {
-            const diffDel = pos - count
-            item = item._splitAt(this._y, diffDel)
-            item._splitAt(this._y, length)
-            length -= item._length
-            item._delete(this._y)
-            count += diffDel
-          } else {
-            count += item._length
-          }
-        }
-        item = item._right
-      }
-    })
-    if (length > 0) {
-      throw new Error('Delete exceeds the range of the YArray')
-    }
-  }
-  insertAfter (left, content) {
-    this._transact(y => {
-      let right
-      if (left === null) {
-        right = this._start
-      } else {
-        right = left._right
-      }
-      let prevJsonIns = null
-      for (let i = 0; i < content.length; i++) {
-        let c = content[i]
-        if (typeof c === 'function') {
-          c = new c() // eslint-disable-line new-cap
-        }
-        if (c instanceof Type) {
-          if (prevJsonIns !== null) {
-            if (y !== null) {
-              prevJsonIns._integrate(y)
-            }
-            left = prevJsonIns
-            prevJsonIns = null
-          }
-          c._origin = left
-          c._left = left
-          c._right = right
-          c._right_origin = right
-          c._parent = this
-          if (y !== null) {
-            c._integrate(y)
-          } else if (left === null) {
-            this._start = c
-          } else {
-            left._right = c
-          }
-          left = c
-        } else {
-          if (prevJsonIns === null) {
-            prevJsonIns = new ItemJSON()
-            prevJsonIns._origin = left
-            prevJsonIns._left = left
-            prevJsonIns._right = right
-            prevJsonIns._right_origin = right
-            prevJsonIns._parent = this
-            prevJsonIns._content = []
-          }
-          prevJsonIns._content.push(c)
-        }
-      }
-      if (prevJsonIns !== null && y !== null) {
-        prevJsonIns._integrate(y)
-      }
-    })
-  }
-  insert (pos, content) {
-    let left = null
-    let right = this._start
-    let count = 0
-    const y = this._y
-    while (right !== null) {
-      const rightLen = right._deleted ? 0 : (right._length - 1)
-      if (count <= pos && pos <= count + rightLen) {
-        const splitDiff = pos - count
-        right = right._splitAt(y, splitDiff)
-        left = right._left
-        count += splitDiff
-        break
-      }
-      if (!right._deleted) {
-        count += right._length
-      }
-      left = right
-      right = right._right
-    }
-    if (pos > count) {
-      throw new Error('Position exceeds array range!')
-    }
-    this.insertAfter(left, content)
-  }
-  _logString () {
-    const left = this._left !== null ? this._left._lastId : null
-    const origin = this._origin !== null ? this._origin._lastId : null
-    return `YArray(id:${logID(this._id)},start:${logID(this._start)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
-  }
-}
--- a/src/Type/YText.js
+++ b/src/Type/YText.js
@@ -1,67 +0,0 @@
-import ItemString from '../Struct/ItemString.js'
-import YArray from './YArray.js'
-import { logID } from '../MessageHandler/messageToString.js'
-
-export default class YText extends YArray {
-  constructor (string) {
-    super()
-    if (typeof string === 'string') {
-      const start = new ItemString()
-      start._parent = this
-      start._content = string
-      this._start = start
-    }
-  }
-  toString () {
-    const strBuilder = []
-    let n = this._start
-    while (n !== null) {
-      if (!n._deleted) {
-        strBuilder.push(n._content)
-      }
-      n = n._right
-    }
-    return strBuilder.join('')
-  }
-  insert (pos, text) {
-    this._transact(y => {
-      let left = null
-      let right = this._start
-      let count = 0
-      while (right !== null) {
-        if (count <= pos && pos < count + right._length) {
-          const splitDiff = pos - count
-          right = right._splitAt(this._y, pos - count)
-          left = right._left
-          count += splitDiff
-          break
-        }
-        count += right._length
-        left = right
-        right = right._right
-      }
-      if (pos > count) {
-        throw new Error('Position exceeds array range!')
-      }
-      let item = new ItemString()
-      item._origin = left
-      item._left = left
-      item._right = right
-      item._right_origin = right
-      item._parent = this
-      item._content = text
-      if (y !== null) {
-        item._integrate(this._y)
-      } else if (left === null) {
-        this._start = item
-      } else {
-        left._right = item
-      }
-    })
-  }
-  _logString () {
-    const left = this._left !== null ? this._left._lastId : null
-    const origin = this._origin !== null ? this._origin._lastId : null
-    return `YText(id:${logID(this._id)},start:${logID(this._start)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
-  }
-}
--- a/src/Type/y-xml/YXmlElement.js
+++ b/src/Type/y-xml/YXmlElement.js
@@ -1,129 +0,0 @@
-// import diff from 'fast-diff'
-import { defaultDomFilter } from './utils.js'
-
-import YMap from '../YMap.js'
-import YXmlFragment from './YXmlFragment.js'
-
-export default class YXmlElement extends YXmlFragment {
-  constructor (arg1, arg2, _document) {
-    super()
-    this.nodeName = null
-    this._scrollElement = null
-    if (typeof arg1 === 'string') {
-      this.nodeName = arg1.toUpperCase()
-    } else if (arg1 != null && arg1.nodeType != null && arg1.nodeType === arg1.ELEMENT_NODE) {
-      this.nodeName = arg1.nodeName
-      this._setDom(arg1, _document)
-    } else {
-      this.nodeName = 'UNDEFINED'
-    }
-    if (typeof arg2 === 'function') {
-      this._domFilter = arg2
-    }
-  }
-  _copy (undeleteChildren) {
-    let struct = super._copy(undeleteChildren)
-    struct.nodeName = this.nodeName
-    return struct
-  }
-  _setDom (dom, _document) {
-    if (this._dom != null) {
-      throw new Error('Only call this method if you know what you are doing ;)')
-    } else if (dom._yxml != null) { // TODO do i need to check this? - no.. but for dev purps..
-      throw new Error('Already bound to an YXml type')
-    } else {
-      // tag is already set in constructor
-      // set attributes
-      let attributes = new Map()
-      for (let i = 0; i < dom.attributes.length; i++) {
-        let attr = dom.attributes[i]
-        attributes.set(attr.name, attr.value)
-      }
-      attributes = this._domFilter(dom, attributes)
-      attributes.forEach((value, name) => {
-        this.setAttribute(name, value)
-      })
-      this.insertDomElements(0, Array.prototype.slice.call(dom.childNodes), _document)
-      this._bindToDom(dom, _document)
-      return dom
-    }
-  }
-  _fromBinary (y, decoder) {
-    const missing = super._fromBinary(y, decoder)
-    this.nodeName = decoder.readVarString()
-    return missing
-  }
-  _toBinary (encoder) {
-    super._toBinary(encoder)
-    encoder.writeVarString(this.nodeName)
-  }
-  _integrate (y) {
-    if (this.nodeName === null) {
-      throw new Error('nodeName must be defined!')
-    }
-    if (this._domFilter === defaultDomFilter && this._parent instanceof YXmlFragment) {
-      this._domFilter = this._parent._domFilter
-    }
-    super._integrate(y)
-  }
-  /**
-   * Returns the string representation of the XML document.
-   * The attributes are ordered by attribute-name, so you can easily use this
-   * method to compare YXmlElements
-   */
-  toString () {
-    const attrs = this.getAttributes()
-    const stringBuilder = []
-    const keys = []
-    for (let key in attrs) {
-      keys.push(key)
-    }
-    keys.sort()
-    const keysLen = keys.length
-    for (let i = 0; i < keysLen; i++) {
-      const key = keys[i]
-      stringBuilder.push(key + '="' + attrs[key] + '"')
-    }
-    const nodeName = this.nodeName.toLocaleLowerCase()
-    const attrsString = stringBuilder.length > 0 ? ' ' + stringBuilder.join(' ') : ''
-    return `<${nodeName}${attrsString}>${super.toString()}</${nodeName}>`
-  }
-  removeAttribute () {
-    return YMap.prototype.delete.apply(this, arguments)
-  }
-
-  setAttribute () {
-    return YMap.prototype.set.apply(this, arguments)
-  }
-
-  getAttribute () {
-    return YMap.prototype.get.apply(this, arguments)
-  }
-
-  getAttributes () {
-    const obj = {}
-    for (let [key, value] of this._map) {
-      if (!value._deleted) {
-        obj[key] = value._content[0]
-      }
-    }
-    return obj
-  }
-  getDom (_document) {
-    _document = _document || document
-    let dom = this._dom
-    if (dom == null) {
-      dom = _document.createElement(this.nodeName)
-      dom._yxml = this
-      let attrs = this.getAttributes()
-      for (let key in attrs) {
-        dom.setAttribute(key, attrs[key])
-      }
-      this.forEach(yxml => {
-        dom.appendChild(yxml.getDom(_document))
-      })
-      this._bindToDom(dom, _document)
-    }
-    return dom
-  }
-}
--- a/src/Type/y-xml/YXmlEvent.js
+++ b/src/Type/y-xml/YXmlEvent.js
@@ -1,17 +0,0 @@
-import YEvent from '../../Util/YEvent.js'
-
-export default class YXmlEvent extends YEvent {
-  constructor (target, subs, remote) {
-    super(target)
-    this.childListChanged = false
-    this.attributesChanged = new Set()
-    this.remote = remote
-    subs.forEach((sub) => {
-      if (sub === null) {
-        this.childListChanged = true
-      } else {
-        this.attributesChanged.add(sub)
-      }
-    })
-  }
-}
--- a/src/Type/y-xml/YXmlFragment.js
+++ b/src/Type/y-xml/YXmlFragment.js
@@ -1,335 +0,0 @@
-/* global MutationObserver */
-
-import { defaultDomFilter, applyChangesFromDom, reflectChangesOnDom } from './utils.js'
-import { beforeTransactionSelectionFixer, afterTransactionSelectionFixer } from './selection.js'
-
-import YArray from '../YArray.js'
-import YXmlText from './YXmlText.js'
-import YXmlEvent from './YXmlEvent.js'
-import { logID } from '../../MessageHandler/messageToString.js'
-import diff from 'fast-diff'
-
-function domToYXml (parent, doms, _document) {
-  const types = []
-  doms.forEach(d => {
-    if (d._yxml != null && d._yxml !== false) {
-      d._yxml._unbindFromDom()
-    }
-    if (parent._domFilter(d.nodeName, new Map()) !== null) {
-      let type
-      if (d.nodeType === d.TEXT_NODE) {
-        type = new YXmlText(d)
-      } else if (d.nodeType === d.ELEMENT_NODE) {
-        type = new YXmlFragment._YXmlElement(d, parent._domFilter, _document)
-      } else {
-        throw new Error('Unsupported node!')
-      }
-      type.enableSmartScrolling(parent._scrollElement)
-      types.push(type)
-    } else {
-      d._yxml = false
-    }
-  })
-  return types
-}
-
-class YXmlTreeWalker {
-  constructor (root, f) {
-    this._filter = f || (() => true)
-    this._root = root
-    this._currentNode = root
-    this._firstCall = true
-  }
-  [Symbol.iterator] () {
-    return this
-  }
-  next () {
-    let n = this._currentNode
-    if (this._firstCall) {
-      this._firstCall = false
-      if (!n._deleted && this._filter(n)) {
-        return { value: n, done: false }
-      }
-    }
-    do {
-      if (!n._deleted && n.constructor === YXmlFragment._YXmlElement && n._start !== null) {
-        // walk down in the tree
-        n = n._start
-      } else {
-        // walk right or up in the tree
-        while (n !== this._root) {
-          if (n._right !== null) {
-            n = n._right
-            break
-          }
-          n = n._parent
-        }
-        if (n === this._root) {
-          n = null
-        }
-      }
-      if (n === this._root) {
-        break
-      }
-    } while (n !== null && (n._deleted || !this._filter(n)))
-    this._currentNode = n
-    if (n === null) {
-      return { done: true }
-    } else {
-      return { value: n, done: false }
-    }
-  }
-}
-
-export default class YXmlFragment extends YArray {
-  constructor () {
-    super()
-    this._dom = null
-    this._domFilter = defaultDomFilter
-    this._domObserver = null
-    // this function makes sure that either the
-    // dom event is executed, or the yjs observer is executed
-    var token = true
-    this._mutualExclude = f => {
-      if (token) {
-        token = false
-        try {
-          f()
-        } catch (e) {
-          console.error(e)
-        }
-        if (this._domObserver !== null) {
-          this._domObserver.takeRecords()
-        }
-        token = true
-      }
-    }
-  }
-  createTreeWalker (filter) {
-    return new YXmlTreeWalker(this, filter)
-  }
-  /**
-   * Retrieve first element that matches *query*
-   * Similar to DOM's querySelector, but only accepts a subset of its queries
-   *
-   * Query support:
-   *   - tagname
-   * TODO:
-   *   - id
-   *   - attribute
-   */
-  querySelector (query) {
-    query = query.toUpperCase()
-    const iterator = new YXmlTreeWalker(this, element => element.nodeName === query)
-    const next = iterator.next()
-    if (next.done) {
-      return null
-    } else {
-      return next.value
-    }
-  }
-  querySelectorAll (query) {
-    query = query.toUpperCase()
-    return Array.from(new YXmlTreeWalker(this, element => element.nodeName === query))
-  }
-  enableSmartScrolling (scrollElement) {
-    this._scrollElement = scrollElement
-    this.forEach(xml => {
-      xml.enableSmartScrolling(scrollElement)
-    })
-  }
-  setDomFilter (f) {
-    this._domFilter = f
-    this.forEach(xml => {
-      xml.setDomFilter(f)
-    })
-  }
-  _callObserver (transaction, parentSubs, remote) {
-    this._callEventHandler(transaction, new YXmlEvent(this, parentSubs, remote))
-  }
-  toString () {
-    return this.map(xml => xml.toString()).join('')
-  }
-  _delete (y, createDelete) {
-    this._unbindFromDom()
-    super._delete(y, createDelete)
-  }
-  _unbindFromDom () {
-    if (this._domObserver != null) {
-      this._domObserver.disconnect()
-      this._domObserver = null
-    }
-    if (this._dom != null) {
-      this._dom._yxml = null
-      this._dom = null
-    }
-  }
-  insertDomElementsAfter (prev, doms, _document) {
-    const types = domToYXml(this, doms, _document)
-    this.insertAfter(prev, types)
-    return types
-  }
-  insertDomElements (pos, doms, _document) {
-    const types = domToYXml(this, doms, _document)
-    this.insert(pos, types)
-    return types
-  }
-  getDom () {
-    return this._dom
-  }
-  bindToDom (dom, _document) {
-    if (this._dom != null) {
-      this._unbindFromDom()
-    }
-    if (dom._yxml != null) {
-      dom._yxml._unbindFromDom()
-    }
-    dom.innerHTML = ''
-    this.forEach(t => {
-      dom.insertBefore(t.getDom(_document), null)
-    })
-    this._bindToDom(dom, _document)
-  }
-  // binds to a dom element
-  // Only call if dom and YXml are isomorph
-  _bindToDom (dom, _document) {
-    _document = _document || document
-    this._dom = dom
-    dom._yxml = this
-    // TODO: refine this..
-    if ((this.constructor !== YXmlFragment && this._parent !== this._y) || this._parent === null) {
-      // TODO: only top level YXmlFragment can bind. Also allow YXmlElements..
-      return
-    }
-    this._y.on('beforeTransaction', beforeTransactionSelectionFixer)
-    this._y.on('afterTransaction', afterTransactionSelectionFixer)
-    const applyFilter = (type) => {
-      if (type._deleted) {
-        return
-      }
-      // check if type is a child of this
-      let isChild = false
-      let p = type
-      while (p !== this._y) {
-        if (p === this) {
-          isChild = true
-          break
-        }
-        p = p._parent
-      }
-      if (!isChild) {
-        return
-      }
-      // filter attributes
-      let attributes = new Map()
-      if (type.getAttributes !== undefined) {
-        let attrs = type.getAttributes()
-        for (let key in attrs) {
-          attributes.set(key, attrs[key])
-        }
-      }
-      let result = this._domFilter(type.nodeName, new Map(attributes))
-      if (result === null) {
-        type._delete(this._y)
-      } else {
-        attributes.forEach((value, key) => {
-          if (!result.has(key)) {
-            type.removeAttribute(key)
-          }
-        })
-      }
-    }
-    this._y.on('beforeObserverCalls', function (y, transaction) {
-      // apply dom filter to new and changed types
-      transaction.changedTypes.forEach(function (subs, type) {
-        if (subs.size > 1 || !subs.has(null)) {
-          // only apply changes on attributes
-          applyFilter(type)
-        }
-      })
-      transaction.newTypes.forEach(applyFilter)
-    })
-    // Apply Y.Xml events to dom
-    this.observeDeep(events => {
-      reflectChangesOnDom.call(this, events, _document)
-    })
-    // Apply Dom changes on Y.Xml
-    if (typeof MutationObserver !== 'undefined') {
-      this._y.on('beforeTransaction', () => {
-        this._domObserverListener(this._domObserver.takeRecords())
-      })
-      this._domObserverListener = mutations => {
-        this._mutualExclude(() => {
-          this._y.transact(() => {
-            let diffChildren = new Set()
-            mutations.forEach(mutation => {
-              const dom = mutation.target
-              const yxml = dom._yxml
-              if (yxml == null) {
-                // dom element is filtered
-                return
-              }
-              switch (mutation.type) {
-                case 'characterData':
-                  var diffs = diff(yxml.toString(), dom.nodeValue)
-                  var pos = 0
-                  for (var i = 0; i < diffs.length; i++) {
-                    var d = diffs[i]
-                    if (d[0] === 0) { // EQUAL
-                      pos += d[1].length
-                    } else if (d[0] === -1) { // DELETE
-                      yxml.delete(pos, d[1].length)
-                    } else { // INSERT
-                      yxml.insert(pos, d[1])
-                      pos += d[1].length
-                    }
-                  }
-                  break
-                case 'attributes':
-                  if (yxml.constructor === YXmlFragment) {
-                    break
-                  }
-                  let name = mutation.attributeName
-                  let val = dom.getAttribute(name)
-                  // check if filter accepts attribute
-                  let attributes = new Map()
-                  attributes.set(name, val)
-                  if (this._domFilter(dom.nodeName, attributes).size > 0 && yxml.constructor !== YXmlFragment) {
-                    if (yxml.getAttribute(name) !== val) {
-                      if (val == null) {
-                        yxml.removeAttribute(name)
-                      } else {
-                        yxml.setAttribute(name, val)
-                      }
-                    }
-                  }
-                  break
-                case 'childList':
-                  diffChildren.add(mutation.target)
-                  break
-              }
-            })
-            for (let dom of diffChildren) {
-              if (dom._yxml != null && dom._yxml !== false) {
-                applyChangesFromDom(dom)
-              }
-            }
-          })
-        })
-      }
-      this._domObserver = new MutationObserver(this._domObserverListener)
-      this._domObserver.observe(dom, {
-        childList: true,
-        attributes: true,
-        characterData: true,
-        subtree: true
-      })
-    }
-    return dom
-  }
-  _logString () {
-    const left = this._left !== null ? this._left._lastId : null
-    const origin = this._origin !== null ? this._origin._lastId : null
-    return `YXml(id:${logID(this._id)},left:${logID(left)},origin:${logID(origin)},right:${this._right},parent:${logID(this._parent)},parentSub:${this._parentSub})`
-  }
-}
--- a/src/Type/y-xml/YXmlText.js
+++ b/src/Type/y-xml/YXmlText.js
@@ -1,93 +0,0 @@
-import YText from '../YText.js'
-
-export default class YXmlText extends YText {
-  constructor (arg1) {
-    let dom = null
-    let initialText = null
-    if (arg1 != null) {
-      if (arg1.nodeType != null && arg1.nodeType === arg1.TEXT_NODE) {
-        dom = arg1
-        initialText = dom.nodeValue
-      } else if (typeof arg1 === 'string') {
-        initialText = arg1
-      }
-    }
-    super(initialText)
-    this._dom = null
-    this._domObserver = null
-    this._domObserverListener = null
-    this._scrollElement = null
-    if (dom !== null) {
-      this._setDom(arg1)
-    }
-    /*
-    var token = true
-    this._mutualExclude = f => {
-      if (token) {
-        token = false
-        try {
-          f()
-        } catch (e) {
-          console.error(e)
-        }
-        this._domObserver.takeRecords()
-        token = true
-      }
-    }
-    this.observe(event => {
-      if (this._dom != null) {
-        const dom = this._dom
-        this._mutualExclude(() => {
-          let anchorViewPosition = getAnchorViewPosition(this._scrollElement)
-          let anchorViewFix
-          if (anchorViewPosition !== null && (anchorViewPosition.anchor !== null || getBoundingClientRect(this._dom).top <= 0)) {
-            anchorViewFix = anchorViewPosition
-          } else {
-            anchorViewFix = null
-          }
-          dom.nodeValue = this.toString()
-          fixScrollPosition(this._scrollElement, anchorViewFix)
-        })
-      }
-    })
-    */
-  }
-  setDomFilter () {}
-  enableSmartScrolling (scrollElement) {
-    this._scrollElement = scrollElement
-  }
-  _setDom (dom) {
-    if (this._dom != null) {
-      this._unbindFromDom()
-    }
-    if (dom._yxml != null) {
-      dom._yxml._unbindFromDom()
-    }
-    // set marker
-    this._dom = dom
-    dom._yxml = this
-  }
-  getDom (_document) {
-    _document = _document || document
-    if (this._dom === null) {
-      const dom = _document.createTextNode(this.toString())
-      this._setDom(dom)
-      return dom
-    }
-    return this._dom
-  }
-  _delete (y, createDelete) {
-    this._unbindFromDom()
-    super._delete(y, createDelete)
-  }
-  _unbindFromDom () {
-    if (this._domObserver != null) {
-      this._domObserver.disconnect()
-      this._domObserver = null
-    }
-    if (this._dom != null) {
-      this._dom._yxml = null
-      this._dom = null
-    }
-  }
-}
--- a/src/Type/y-xml/utils.js
+++ b/src/Type/y-xml/utils.js
@@ -1,252 +0,0 @@
-import YXmlText from './YXmlText.js'
-
-export function defaultDomFilter (node, attributes) {
-  return attributes
-}
-
-export function getAnchorViewPosition (scrollElement) {
-  if (scrollElement == null) {
-    return null
-  }
-  let anchor = document.getSelection().anchorNode
-  if (anchor != null) {
-    let top = getBoundingClientRect(anchor).top
-    if (top >= 0 && top <= document.documentElement.clientHeight) {
-      return {
-        anchor: anchor,
-        top: top
-      }
-    }
-  }
-  return {
-    anchor: null,
-    scrollTop: scrollElement.scrollTop,
-    scrollHeight: scrollElement.scrollHeight
-  }
-}
-
-// get BoundingClientRect that works on text nodes
-export function getBoundingClientRect (element) {
-  if (element.getBoundingClientRect != null) {
-    // is element node
-    return element.getBoundingClientRect()
-  } else {
-    // is text node
-    if (element.parentNode == null) {
-      // range requires that text nodes have a parent
-      let span = document.createElement('span')
-      span.appendChild(element)
-    }
-    let range = document.createRange()
-    range.selectNode(element)
-    return range.getBoundingClientRect()
-  }
-}
-
-export function fixScrollPosition (scrollElement, fix) {
-  if (scrollElement !== null && fix !== null) {
-    if (fix.anchor === null) {
-      if (scrollElement.scrollTop === fix.scrollTop) {
-        scrollElement.scrollTop = scrollElement.scrollHeight - fix.scrollHeight
-      }
-    } else {
-      scrollElement.scrollTop = getBoundingClientRect(fix.anchor).top - fix.top
-    }
-  }
-}
-
-function iterateUntilUndeleted (item) {
-  while (item !== null && item._deleted) {
-    item = item._right
-  }
-  return item
-}
-
-function _insertNodeHelper (yxml, prevExpectedNode, child) {
-  let insertedNodes = yxml.insertDomElementsAfter(prevExpectedNode, [child])
-  if (insertedNodes.length > 0) {
-    return insertedNodes[0]
-  } else {
-    return prevExpectedNode
-  }
-}
-
-/*
- * 1. Check if any of the nodes was deleted
- * 2. Iterate over the children.
- *    2.1 If a node exists without _yxml property, insert a new node
- *    2.2 If _contents.length < dom.childNodes.length, fill the
- *        rest of _content with childNodes
- *    2.3 If a node was moved, delete it and
- *       recreate a new yxml element that is bound to that node.
- *       You can detect that a node was moved because expectedId
- *       !== actualId in the list
- */
-export function applyChangesFromDom (dom) {
-  const yxml = dom._yxml
-  const y = yxml._y
-  let knownChildren =
-    new Set(
-      Array.prototype.map.call(dom.childNodes, child => child._yxml)
-      .filter(id => id !== undefined)
-    )
-  // 1. Check if any of the nodes was deleted
-  yxml.forEach(function (childType, i) {
-    if (!knownChildren.has(childType)) {
-      childType._delete(y)
-    }
-  })
-  // 2. iterate
-  let childNodes = dom.childNodes
-  let len = childNodes.length
-  let prevExpectedNode = null
-  let expectedNode = iterateUntilUndeleted(yxml._start)
-  for (let domCnt = 0; domCnt < len; domCnt++) {
-    const child = childNodes[domCnt]
-    const childYXml = child._yxml
-    if (childYXml != null) {
-      if (childYXml === false) {
-        // should be ignored or is going to be deleted
-        continue
-      }
-      if (expectedNode !== null) {
-        if (expectedNode !== childYXml) {
-          // 2.3 Not expected node
-          if (childYXml._parent !== this) {
-            // element is going to be deleted by its previous parent
-            child._yxml = null
-          } else {
-            childYXml._delete(y)
-          }
-          prevExpectedNode = _insertNodeHelper(yxml, prevExpectedNode, child)
-        } else {
-          prevExpectedNode = expectedNode
-          expectedNode = iterateUntilUndeleted(expectedNode._right)
-        }
-        // if this is the expected node id, just continue
-      } else {
-        // 2.2 fill _conten with child nodes
-        prevExpectedNode = _insertNodeHelper(yxml, prevExpectedNode, child)
-      }
-    } else {
-      // 2.1 A new node was found
-      prevExpectedNode = _insertNodeHelper(yxml, prevExpectedNode, child)
-    }
-  }
-}
-
-export function reflectChangesOnDom (events, _document) {
-  // Make sure that no filtered attributes are applied to the structure
-  // if they were, delete them
-  /*
-  events.forEach(event => {
-    const target = event.target
-    if (event.attributesChanged === undefined) {
-      // event.target is Y.XmlText
-      return
-    }
-    const keys = this._domFilter(target.nodeName, Array.from(event.attributesChanged))
-    if (keys === null) {
-      target._delete()
-    } else {
-      const removeKeys = new Set() // is a copy of event.attributesChanged
-      event.attributesChanged.forEach(key => { removeKeys.add(key) })
-      keys.forEach(key => {
-        // remove all accepted keys from removeKeys
-        removeKeys.delete(key)
-      })
-      // remove the filtered attribute
-      removeKeys.forEach(key => {
-        target.removeAttribute(key)
-      })
-    }
-  })
-  */
-  this._mutualExclude(() => {
-    events.forEach(event => {
-      const yxml = event.target
-      const dom = yxml._dom
-      if (dom != null) {
-        // TODO: do this once before applying stuff
-        // let anchorViewPosition = getAnchorViewPosition(yxml._scrollElement)
-        if (yxml.constructor === YXmlText) {
-          yxml._dom.nodeValue = yxml.toString()
-        } else {
-          // update attributes
-          event.attributesChanged.forEach(attributeName => {
-            const value = yxml.getAttribute(attributeName)
-            if (value === undefined) {
-              dom.removeAttribute(attributeName)
-            } else {
-              dom.setAttribute(attributeName, value)
-            }
-          })
-          if (event.childListChanged) {
-            // create fragment of undeleted nodes
-            const fragment = _document.createDocumentFragment()
-            yxml.forEach(function (t) {
-              fragment.appendChild(t.getDom(_document))
-            })
-            // remove remainding nodes
-            let lastChild = dom.lastChild
-            while (lastChild !== null) {
-              dom.removeChild(lastChild)
-              lastChild = dom.lastChild
-            }
-            // insert fragment of undeleted nodes
-            dom.appendChild(fragment)
-          }
-        }
-        /* TODO: smartscrolling
-        .. else if (event.type === 'childInserted' || event.type === 'insert') {
-          let nodes = event.values
-          for (let i = nodes.length - 1; i >= 0; i--) {
-            let node = nodes[i]
-            node.setDomFilter(yxml._domFilter)
-            node.enableSmartScrolling(yxml._scrollElement)
-            let dom = node.getDom()
-            let fixPosition = null
-            let nextDom = null
-            if (yxml._content.length > event.index + i + 1) {
-              nextDom = yxml.get(event.index + i + 1).getDom()
-            }
-            yxml._dom.insertBefore(dom, nextDom)
-            if (anchorViewPosition === null) {
-              // nop
-            } else if (anchorViewPosition.anchor !== null) {
-              // no scrolling when current selection
-              if (!dom.contains(anchorViewPosition.anchor) && !anchorViewPosition.anchor.contains(dom)) {
-                fixPosition = anchorViewPosition
-              }
-            } else if (getBoundingClientRect(dom).top <= 0) {
-              // adjust scrolling if modified element is out of view,
-              // there is no anchor element, and the browser did not adjust scrollTop (this is checked later)
-              fixPosition = anchorViewPosition
-            }
-            fixScrollPosition(yxml._scrollElement, fixPosition)
-          }
-        } else if (event.type === 'childRemoved' || event.type === 'delete') {
-          for (let i = event.values.length - 1; i >= 0; i--) {
-            let dom = event.values[i]._dom
-            let fixPosition = null
-            if (anchorViewPosition === null) {
-              // nop
-            } else if (anchorViewPosition.anchor !== null) {
-              // no scrolling when current selection
-              if (!dom.contains(anchorViewPosition.anchor) && !anchorViewPosition.anchor.contains(dom)) {
-                fixPosition = anchorViewPosition
-              }
-            } else if (getBoundingClientRect(dom).top <= 0) {
-              // adjust scrolling if modified element is out of view,
-              // there is no anchor element, and the browser did not adjust scrollTop (this is checked later)
-              fixPosition = anchorViewPosition
-            }
-            dom.remove()
-            fixScrollPosition(yxml._scrollElement, fixPosition)
-          }
-        }
-        */
-      }
-    })
-  })
-}
--- a/src/Type/y-xml/y-xml.js
+++ b/src/Type/y-xml/y-xml.js
@@ -1,9 +0,0 @@
-
-import YXmlFragment from './YXmlFragment.js'
-import YXmlElement from './YXmlElement.js'
-
-export { default as YXmlFragment } from './YXmlFragment.js'
-export { default as YXmlElement } from './YXmlElement.js'
-export { default as YXmlText } from './YXmlText.js'
-
-YXmlFragment._YXmlElement = YXmlElement
--- a/src/Types/YArray/YArray.mjs
+++ b/src/Types/YArray/YArray.mjs
@@ -0,0 +1,378 @@
+import Type from '../../Struct/Type.mjs'
+import ItemJSON from '../../Struct/ItemJSON.mjs'
+import ItemString from '../../Struct/ItemString.mjs'
+import { logID, logItemHelper } from '../../MessageHandler/messageToString.mjs'
+import YEvent from '../../Util/YEvent.mjs'
+
+/**
+ * Event that describes the changes on a YArray
+ *
+ * @param {YArray} yarray The changed type
+ * @param {Boolean} remote Whether the changed was caused by a remote peer
+ * @param {Transaction} transaction The transaction object
+ */
+export class YArrayEvent extends YEvent {
+  constructor (yarray, remote, transaction) {
+    super(yarray)
+    this.remote = remote
+    this._transaction = transaction
+    this._addedElements = null
+    this._removedElements = null
+  }
+
+  /**
+   * Child elements that were added in this transaction.
+   *
+   * @return {Set}
+   */
+  get addedElements () {
+    if (this._addedElements === null) {
+      const target = this.target
+      const transaction = this._transaction
+      const addedElements = new Set()
+      transaction.newTypes.forEach(function (type) {
+        if (type._parent === target && !transaction.deletedStructs.has(type)) {
+          addedElements.add(type)
+        }
+      })
+      this._addedElements = addedElements
+    }
+    return this._addedElements
+  }
+
+  /**
+   * Child elements that were removed in this transaction.
+   *
+   * @return {Set}
+   */
+  get removedElements () {
+    if (this._removedElements === null) {
+      const target = this.target
+      const transaction = this._transaction
+      const removedElements = new Set()
+      transaction.deletedStructs.forEach(function (struct) {
+        if (struct._parent === target && !transaction.newTypes.has(struct)) {
+          removedElements.add(struct)
+        }
+      })
+      this._removedElements = removedElements
+    }
+    return this._removedElements
+  }
+}
+
+/**
+ * A shared Array implementation.
+ */
+export default class YArray extends Type {
+  /**
+   * @private
+   * Creates YArray Event and calls observers.
+   */
+  _callObserver (transaction, parentSubs, remote) {
+    this._callEventHandler(transaction, new YArrayEvent(this, remote, transaction))
+  }
+
+  /**
+   * Returns the i-th element from a YArray.
+   *
+   * @param {Integer} index The index of the element to return from the YArray
+   */
+  get (index) {
+    let n = this._start
+    while (n !== null) {
+      if (!n._deleted && n._countable) {
+        if (index < n._length) {
+          if (n.constructor === ItemJSON || n.constructor === ItemString) {
+            return n._content[index]
+          } else {
+            return n
+          }
+        }
+        index -= n._length
+      }
+      n = n._right
+    }
+  }
+
+  /**
+   * Transforms this YArray to a JavaScript Array.
+   *
+   * @return {Array}
+   */
+  toArray () {
+    return this.map(c => c)
+  }
+
+  /**
+   * Transforms this Shared Type to a JSON object.
+   *
+   * @return {Array}
+   */
+  toJSON () {
+    return this.map(c => {
+      if (c instanceof Type) {
+        if (c.toJSON !== null) {
+          return c.toJSON()
+        } else {
+          return c.toString()
+        }
+      }
+      return c
+    })
+  }
+
+  /**
+   * Returns an Array with the result of calling a provided function on every
+   * element of this YArray.
+   *
+   * @param {Function} f Function that produces an element of the new Array
+   * @return {Array} A new array with each element being the result of the
+   *                 callback function
+   */
+  map (f) {
+    const res = []
+    this.forEach((c, i) => {
+      res.push(f(c, i, this))
+    })
+    return res
+  }
+
+  /**
+   * Executes a provided function on once on overy element of this YArray.
+   *
+   * @param {Function} f A function to execute on every element of this YArray.
+   */
+  forEach (f) {
+    let index = 0
+    let n = this._start
+    while (n !== null) {
+      if (!n._deleted && n._countable) {
+        if (n instanceof Type) {
+          f(n, index++, this)
+        } else {
+          const content = n._content
+          const contentLen = content.length
+          for (let i = 0; i < contentLen; i++) {
+            index++
+            f(content[i], index, this)
+          }
+        }
+      }
+      n = n._right
+    }
+  }
+
+  /**
+   * Computes the length of this YArray.
+   */
+  get length () {
+    let length = 0
+    let n = this._start
+    while (n !== null) {
+      if (!n._deleted && n._countable) {
+        length += n._length
+      }
+      n = n._right
+    }
+    return length
+  }
+
+  [Symbol.iterator] () {
+    return {
+      next: function () {
+        while (this._item !== null && (this._item._deleted || this._item._length <= this._itemElement)) {
+          // item is deleted or itemElement does not exist (is deleted)
+          this._item = this._item._right
+          this._itemElement = 0
+        }
+        if (this._item === null) {
+          return {
+            done: true
+          }
+        }
+        let content
+        if (this._item instanceof Type) {
+          content = this._item
+        } else {
+          content = this._item._content[this._itemElement++]
+        }
+        return {
+          value: content,
+          done: false
+        }
+      },
+      _item: this._start,
+      _itemElement: 0,
+      _count: 0
+    }
+  }
+
+  /**
+   * Deletes elements starting from an index.
+   *
+   * @param {Integer} index Index at which to start deleting elements
+   * @param {Integer} length The number of elements to remove. Defaults to 1.
+   */
+  delete (index, length = 1) {
+    this._y.transact(() => {
+      let item = this._start
+      let count = 0
+      while (item !== null && length > 0) {
+        if (!item._deleted && item._countable) {
+          if (count <= index && index < count + item._length) {
+            const diffDel = index - count
+            item = item._splitAt(this._y, diffDel)
+            item._splitAt(this._y, length)
+            length -= item._length
+            item._delete(this._y)
+            count += diffDel
+          } else {
+            count += item._length
+          }
+        }
+        item = item._right
+      }
+    })
+    if (length > 0) {
+      throw new Error('Delete exceeds the range of the YArray')
+    }
+  }
+
+  /**
+   * @private
+   * Inserts content after an element container.
+   *
+   * @param {Item} left The element container to use as a reference.
+   * @param {Array} content The Array of content to insert (see {@see insert})
+   */
+  insertAfter (left, content) {
+    this._transact(y => {
+      let right
+      if (left === null) {
+        right = this._start
+      } else {
+        right = left._right
+      }
+      let prevJsonIns = null
+      for (let i = 0; i < content.length; i++) {
+        let c = content[i]
+        if (typeof c === 'function') {
+          c = new c() // eslint-disable-line new-cap
+        }
+        if (c instanceof Type) {
+          if (prevJsonIns !== null) {
+            if (y !== null) {
+              prevJsonIns._integrate(y)
+            }
+            left = prevJsonIns
+            prevJsonIns = null
+          }
+          c._origin = left
+          c._left = left
+          c._right = right
+          c._right_origin = right
+          c._parent = this
+          if (y !== null) {
+            c._integrate(y)
+          } else if (left === null) {
+            this._start = c
+          } else {
+            left._right = c
+          }
+          left = c
+        } else {
+          if (prevJsonIns === null) {
+            prevJsonIns = new ItemJSON()
+            prevJsonIns._origin = left
+            prevJsonIns._left = left
+            prevJsonIns._right = right
+            prevJsonIns._right_origin = right
+            prevJsonIns._parent = this
+            prevJsonIns._content = []
+          }
+          prevJsonIns._content.push(c)
+        }
+      }
+      if (prevJsonIns !== null) {
+        if (y !== null) {
+          prevJsonIns._integrate(y)
+        } else if (prevJsonIns._left === null) {
+          this._start = prevJsonIns
+        }
+      }
+    })
+    return content
+  }
+
+  /**
+   * Inserts new content at an index.
+   *
+   * Important: This function expects an array of content. Not just a content
+   * object. The reason for this "weirdness" is that inserting several elements
+   * is very efficient when it is done as a single operation.
+   *
+   * @example
+   *  // Insert character 'a' at position 0
+   *  yarray.insert(0, ['a'])
+   *  // Insert numbers 1, 2 at position 1
+   *  yarray.insert(2, [1, 2])
+   *
+   * @param {Integer} index The index to insert content at.
+   * @param {Array} content The array of content
+   */
+  insert (index, content) {
+    this._transact(() => {
+      let left = null
+      let right = this._start
+      let count = 0
+      const y = this._y
+      while (right !== null) {
+        const rightLen = right._deleted ? 0 : (right._length - 1)
+        if (count <= index && index <= count + rightLen) {
+          const splitDiff = index - count
+          right = right._splitAt(y, splitDiff)
+          left = right._left
+          count += splitDiff
+          break
+        }
+        if (!right._deleted) {
+          count += right._length
+        }
+        left = right
+        right = right._right
+      }
+      if (index > count) {
+        throw new Error('Index exceeds array range!')
+      }
+      this.insertAfter(left, content)
+    })
+  }
+
+  /**
+   * Appends content to this YArray.
+   *
+   * @param {Array} content Array of content to append.
+   */
+  push (content) {
+    let n = this._start
+    let lastUndeleted = null
+    while (n !== null) {
+      if (!n._deleted) {
+        lastUndeleted = n
+      }
+      n = n._right
+    }
+    this.insertAfter(lastUndeleted, content)
+  }
+
+  /**
+   * Transform this YXml Type to a readable format.
+   * Useful for logging as all Items and Delete implement this method.
+   *
+   * @private
+   */
+  _logString () {
+    return logItemHelper('YArray', this, `start:${logID(this._start)}"`)
+  }
+}
--- a/src/Types/YMap/YMap.mjs
+++ b/src/Types/YMap/YMap.mjs
@@ -1,10 +1,17 @@
-import Type from '../Struct/Type.js'
-import Item from '../Struct/Item.js'
-import ItemJSON from '../Struct/ItemJSON.js'
-import { logID } from '../MessageHandler/messageToString.js'
-import YEvent from '../Util/YEvent.js'
+import Item from '../../Struct/Item.mjs'
+import Type from '../../Struct/Type.mjs'
+import ItemJSON from '../../Struct/ItemJSON.mjs'
+import { logItemHelper } from '../../MessageHandler/messageToString.mjs'
+import YEvent from '../../Util/YEvent.mjs'

-class YMapEvent extends YEvent {
+/**
+ * Event that describes the changes on a YMap.
+ *
+ * @param {YMap} ymap The YArray that changed.
+ * @param {Set<any>} subs The keys that changed.
+ * @param {boolean} remote Whether the change was created by a remote peer.
+ */
+export class YMapEvent extends YEvent {
  constructor (ymap, subs, remote) {
    super(ymap)
    this.keysChanged = subs
@@ -12,10 +19,23 @@ class YMapEvent extends YEvent {
  }
 }

+/**
+ * A shared Map implementation.
+ */
 export default class YMap extends Type {
+  /**
+   * @private
+   * Creates YMap Event and calls observers.
+   */
  _callObserver (transaction, parentSubs, remote) {
    this._callEventHandler(transaction, new YMapEvent(this, parentSubs, remote))
  }
+
+  /**
+   * Transforms this Shared Type to a JSON object.
+   *
+   * @return {Object}
+   */
  toJSON () {
    const map = {}
    for (let [key, item] of this._map) {
@@ -35,7 +55,14 @@ export default class YMap extends Type {
    }
    return map
  }
+
+  /**
+   * Returns the keys for each element in the YMap Type.
+   *
+   * @return {Array}
+   */
  keys () {
+    // TODO: Should return either Iterator or Set!
    let keys = []
    for (let [key, value] of this._map) {
      if (!value._deleted) {
@@ -44,6 +71,12 @@ export default class YMap extends Type {
    }
    return keys
  }
+
+  /**
+   * Remove a specified element from this YMap.
+   *
+   * @param {encodable} key The key of the element to remove.
+   */
  delete (key) {
    this._transact((y) => {
      let c = this._map.get(key)
@@ -52,11 +85,22 @@ export default class YMap extends Type {
      }
    })
  }
+
+  /**
+   * Adds or updates an element with a specified key and value.
+   *
+   * @param {encodable} key The key of the element to add to this YMap.
+   * @param {encodable | YType} value The value of the element to add to this
+   *                                  YMap.
+   */
  set (key, value) {
    this._transact(y => {
      const old = this._map.get(key) || null
      if (old !== null) {
-        if (old instanceof ItemJSON && old._content[0] === value) {
+        if (
+          old.constructor === ItemJSON &&
+          !old._deleted && old._content[0] === value
+        ) {
          // Trying to overwrite with same value
          // break here
          return value
@@ -87,6 +131,12 @@ export default class YMap extends Type {
    })
    return value
  }
+
+  /**
+   * Returns a specified element from this YMap.
+   *
+   * @param {encodable} key The key of the element to return.
+   */
  get (key) {
    let v = this._map.get(key)
    if (v === undefined || v._deleted) {
@@ -98,6 +148,12 @@ export default class YMap extends Type {
      return v._content[v._content.length - 1]
    }
  }
+
+  /**
+   * Returns a boolean indicating whether the specified key exists or not.
+   *
+   * @param {encodable} key The key to test.
+   */
  has (key) {
    let v = this._map.get(key)
    if (v === undefined || v._deleted) {
@@ -106,9 +162,14 @@ export default class YMap extends Type {
      return true
    }
  }
+
+  /**
+   * Transform this YXml Type to a readable format.
+   * Useful for logging as all Items and Delete implement this method.
+   *
+   * @private
+   */
  _logString () {
-    const left = this._left !== null ? this._left._lastId : null
-    const origin = this._origin !== null ? this._origin._lastId : null
-    return `YMap(id:${logID(this._id)},mapSize:${this._map.size},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
+    return logItemHelper('YMap', this, `mapSize:${this._map.size}`)
  }
 }
--- a/src/Types/YText/YText.mjs
+++ b/src/Types/YText/YText.mjs
@@ -0,0 +1,656 @@
+import ItemEmbed from '../../Struct/ItemEmbed.mjs'
+import ItemString from '../../Struct/ItemString.mjs'
+import ItemFormat from '../../Struct/ItemFormat.mjs'
+import { logItemHelper } from '../../MessageHandler/messageToString.mjs'
+import { YArrayEvent, default as YArray } from '../YArray/YArray.mjs'
+
+/**
+ * @private
+ */
+function integrateItem (item, parent, y, left, right) {
+  item._origin = left
+  item._left = left
+  item._right = right
+  item._right_origin = right
+  item._parent = parent
+  if (y !== null) {
+    item._integrate(y)
+  } else if (left === null) {
+    parent._start = item
+  } else {
+    left._right = item
+  }
+}
+
+/**
+ * @private
+ */
+function findNextPosition (currentAttributes, parent, left, right, count) {
+  while (right !== null && count > 0) {
+    switch (right.constructor) {
+      case ItemEmbed:
+      case ItemString:
+        const rightLen = right._deleted ? 0 : (right._length - 1)
+        if (count <= rightLen) {
+          right = right._splitAt(parent._y, count)
+          left = right._left
+          return [left, right, currentAttributes]
+        }
+        if (right._deleted === false) {
+          count -= right._length
+        }
+        break
+      case ItemFormat:
+        if (right._deleted === false) {
+          updateCurrentAttributes(currentAttributes, right)
+        }
+        break
+    }
+    left = right
+    right = right._right
+  }
+  return [left, right, currentAttributes]
+}
+
+/**
+ * @private
+ */
+function findPosition (parent, index) {
+  let currentAttributes = new Map()
+  let left = null
+  let right = parent._start
+  return findNextPosition(currentAttributes, parent, left, right, index)
+}
+
+/**
+ * Negate applied formats
+ *
+ * @private
+ */
+function insertNegatedAttributes (y, parent, left, right, negatedAttributes) {
+  // check if we really need to remove attributes
+  while (
+    right !== null && (
+      right._deleted === true || (
+        right.constructor === ItemFormat &&
+        (negatedAttributes.get(right.key) === right.value)
+      )
+    )
+  ) {
+    if (right._deleted === false) {
+      negatedAttributes.delete(right.key)
+    }
+    left = right
+    right = right._right
+  }
+  for (let [key, val] of negatedAttributes) {
+    let format = new ItemFormat()
+    format.key = key
+    format.value = val
+    integrateItem(format, parent, y, left, right)
+    left = format
+  }
+  return [left, right]
+}
+
+/**
+ * @private
+ */
+function updateCurrentAttributes (currentAttributes, item) {
+  const value = item.value
+  const key = item.key
+  if (value === null) {
+    currentAttributes.delete(key)
+  } else {
+    currentAttributes.set(key, value)
+  }
+}
+
+/**
+ * @private
+ */
+function minimizeAttributeChanges (left, right, currentAttributes, attributes) {
+  // go right while attributes[right.key] === right.value (or right is deleted)
+  while (true) {
+    if (right === null) {
+      break
+    } else if (right._deleted === true) {
+      // continue
+    } else if (right.constructor === ItemFormat && (attributes[right.key] || null) === right.value) {
+      // found a format, update currentAttributes and continue
+      updateCurrentAttributes(currentAttributes, right)
+    } else {
+      break
+    }
+    left = right
+    right = right._right
+  }
+  return [left, right]
+}
+
+/**
+ * @private
+ */
+function insertAttributes (y, parent, left, right, attributes, currentAttributes) {
+  const negatedAttributes = new Map()
+  // insert format-start items
+  for (let key in attributes) {
+    const val = attributes[key]
+    const currentVal = currentAttributes.get(key)
+    if (currentVal !== val) {
+      // save negated attribute (set null if currentVal undefined)
+      negatedAttributes.set(key, currentVal || null)
+      let format = new ItemFormat()
+      format.key = key
+      format.value = val
+      integrateItem(format, parent, y, left, right)
+      left = format
+    }
+  }
+  return [left, right, negatedAttributes]
+}
+
+/**
+ * @private
+ */
+function insertText (y, text, parent, left, right, currentAttributes, attributes) {
+  for (let [key] of currentAttributes) {
+    if (attributes[key] === undefined) {
+      attributes[key] = null
+    }
+  }
+  [left, right] = minimizeAttributeChanges(left, right, currentAttributes, attributes)
+  let negatedAttributes
+  [left, right, negatedAttributes] = insertAttributes(y, parent, left, right, attributes, currentAttributes)
+  // insert content
+  let item
+  if (text.constructor === String) {
+    item = new ItemString()
+    item._content = text
+  } else {
+    item = new ItemEmbed()
+    item.embed = text
+  }
+  integrateItem(item, parent, y, left, right)
+  left = item
+  return insertNegatedAttributes(y, parent, left, right, negatedAttributes)
+}
+
+/**
+ * @private
+ */
+function formatText (y, length, parent, left, right, currentAttributes, attributes) {
+  [left, right] = minimizeAttributeChanges(left, right, currentAttributes, attributes)
+  let negatedAttributes
+  [left, right, negatedAttributes] = insertAttributes(y, parent, left, right, attributes, currentAttributes)
+  // iterate until first non-format or null is found
+  // delete all formats with attributes[format.key] != null
+  while (length > 0 && right !== null) {
+    if (right._deleted === false) {
+      switch (right.constructor) {
+        case ItemFormat:
+          const attr = attributes[right.key]
+          if (attr !== undefined) {
+            if (attr === right.value) {
+              negatedAttributes.delete(right.key)
+            } else {
+              negatedAttributes.set(right.key, right.value)
+            }
+            right._delete(y)
+          }
+          updateCurrentAttributes(currentAttributes, right)
+          break
+        case ItemEmbed:
+        case ItemString:
+          right._splitAt(y, length)
+          length -= right._length
+          break
+      }
+    }
+    left = right
+    right = right._right
+  }
+  return insertNegatedAttributes(y, parent, left, right, negatedAttributes)
+}
+
+/**
+ * @private
+ */
+function deleteText (y, length, parent, left, right, currentAttributes) {
+  while (length > 0 && right !== null) {
+    if (right._deleted === false) {
+      switch (right.constructor) {
+        case ItemFormat:
+          updateCurrentAttributes(currentAttributes, right)
+          break
+        case ItemEmbed:
+        case ItemString:
+          right._splitAt(y, length)
+          length -= right._length
+          right._delete(y)
+          break
+      }
+    }
+    left = right
+    right = right._right
+  }
+  return [left, right]
+}
+
+// TODO: In the quill delta representation we should also use the format {ops:[..]}
+/**
+ * The Quill Delta format represents changes on a text document with
+ * formatting information. For mor information visit {@link https://quilljs.com/docs/delta/|Quill Delta}
+ *
+ * @example
+ *   {
+ *     ops: [
+ *       { insert: 'Gandalf', attributes: { bold: true } },
+ *       { insert: ' the ' },
+ *       { insert: 'Grey', attributes: { color: '#cccccc' } }
+ *     ]
+ *   }
+ *
+ * @typedef {Array<Object>} Delta
+ */
+
+ /**
+  * Attributes that can be assigned to a selection of text.
+  *
+  * @example
+  *   {
+  *     bold: true,
+  *     font-size: '40px'
+  *   }
+  *
+  * @typedef {Object} TextAttributes
+  */
+
+/**
+ * Event that describes the changes on a YText type.
+ *
+ * @private
+ */
+class YTextEvent extends YArrayEvent {
+  constructor (ytext, remote, transaction) {
+    super(ytext, remote, transaction)
+    this._delta = null
+  }
+  // TODO: Should put this in a separate function. toDelta shouldn't be included
+  //       in every Yjs distribution
+  /**
+   * Compute the changes in the delta format.
+   *
+   * @return {Delta} A {@link https://quilljs.com/docs/delta/|Quill Delta}) that
+   *                 represents the changes on the document.
+   *
+   * @public
+   */
+  get delta () {
+    if (this._delta === null) {
+      const y = this.target._y
+      y.transact(() => {
+        let item = this.target._start
+        const delta = []
+        const added = this.addedElements
+        const removed = this.removedElements
+        this._delta = delta
+        let action = null
+        let attributes = {} // counts added or removed new attributes for retain
+        const currentAttributes = new Map() // saves all current attributes for insert
+        const oldAttributes = new Map()
+        let insert = ''
+        let retain = 0
+        let deleteLen = 0
+        const addOp = function addOp () {
+          if (action !== null) {
+            let op
+            switch (action) {
+              case 'delete':
+                op = { delete: deleteLen }
+                deleteLen = 0
+                break
+              case 'insert':
+                op = { insert }
+                if (currentAttributes.size > 0) {
+                  op.attributes = {}
+                  for (let [key, value] of currentAttributes) {
+                    if (value !== null) {
+                      op.attributes[key] = value
+                    }
+                  }
+                }
+                insert = ''
+                break
+              case 'retain':
+                op = { retain }
+                if (Object.keys(attributes).length > 0) {
+                  op.attributes = {}
+                  for (let key in attributes) {
+                    op.attributes[key] = attributes[key]
+                  }
+                }
+                retain = 0
+                break
+            }
+            delta.push(op)
+            action = null
+          }
+        }
+        while (item !== null) {
+          switch (item.constructor) {
+            case ItemEmbed:
+              if (added.has(item)) {
+                addOp()
+                action = 'insert'
+                insert = item.embed
+                addOp()
+              } else if (removed.has(item)) {
+                if (action !== 'delete') {
+                  addOp()
+                  action = 'delete'
+                }
+                deleteLen += 1
+              } else if (item._deleted === false) {
+                if (action !== 'retain') {
+                  addOp()
+                  action = 'retain'
+                }
+                retain += 1
+              }
+              break
+            case ItemString:
+              if (added.has(item)) {
+                if (action !== 'insert') {
+                  addOp()
+                  action = 'insert'
+                }
+                insert += item._content
+              } else if (removed.has(item)) {
+                if (action !== 'delete') {
+                  addOp()
+                  action = 'delete'
+                }
+                deleteLen += item._length
+              } else if (item._deleted === false) {
+                if (action !== 'retain') {
+                  addOp()
+                  action = 'retain'
+                }
+                retain += item._length
+              }
+              break
+            case ItemFormat:
+              if (added.has(item)) {
+                const curVal = currentAttributes.get(item.key) || null
+                if (curVal !== item.value) {
+                  if (action === 'retain') {
+                    addOp()
+                  }
+                  if (item.value === (oldAttributes.get(item.key) || null)) {
+                    delete attributes[item.key]
+                  } else {
+                    attributes[item.key] = item.value
+                  }
+                } else {
+                  item._delete(y)
+                }
+              } else if (removed.has(item)) {
+                oldAttributes.set(item.key, item.value)
+                const curVal = currentAttributes.get(item.key) || null
+                if (curVal !== item.value) {
+                  if (action === 'retain') {
+                    addOp()
+                  }
+                  attributes[item.key] = curVal
+                }
+              } else if (item._deleted === false) {
+                oldAttributes.set(item.key, item.value)
+                const attr = attributes[item.key]
+                if (attr !== undefined) {
+                  if (attr !== item.value) {
+                    if (action === 'retain') {
+                      addOp()
+                    }
+                    if (item.value === null) {
+                      attributes[item.key] = item.value
+                    } else {
+                      delete attributes[item.key]
+                    }
+                  } else {
+                    item._delete(y)
+                  }
+                }
+              }
+              if (item._deleted === false) {
+                if (action === 'insert') {
+                  addOp()
+                }
+                updateCurrentAttributes(currentAttributes, item)
+              }
+              break
+          }
+          item = item._right
+        }
+        addOp()
+        while (this._delta.length > 0) {
+          let lastOp = this._delta[this._delta.length - 1]
+          if (lastOp.retain !== undefined && lastOp.attributes === undefined) {
+            // retain delta's if they don't assign attributes
+            this._delta.pop()
+          } else {
+            break
+          }
+        }
+      })
+    }
+    return this._delta
+  }
+}
+
+/**
+ * Type that represents text with formatting information.
+ *
+ * This type replaces y-richtext as this implementation is able to handle
+ * block formats (format information on a paragraph), embeds (complex elements
+ * like pictures and videos), and text formats (**bold**, *italic*).
+ *
+ * @param {String} string The initial value of the YText.
+ */
+export default class YText extends YArray {
+  constructor (string) {
+    super()
+    if (typeof string === 'string') {
+      const start = new ItemString()
+      start._parent = this
+      start._content = string
+      this._start = start
+    }
+  }
+
+  /**
+   * @private
+   * Creates YMap Event and calls observers.
+   */
+  _callObserver (transaction, parentSubs, remote) {
+    this._callEventHandler(transaction, new YTextEvent(this, remote, transaction))
+  }
+
+  /**
+   * Returns the unformatted string representation of this YText type.
+   *
+   * @public
+   */
+  toString () {
+    let str = ''
+    let n = this._start
+    while (n !== null) {
+      if (!n._deleted && n._countable) {
+        str += n._content
+      }
+      n = n._right
+    }
+    return str
+  }
+
+  /**
+   * Apply a {@link Delta} on this shared YText type.
+   *
+   * @param {Delta} delta The changes to apply on this element.
+   *
+   * @public
+   */
+  applyDelta (delta) {
+    this._transact(y => {
+      let left = null
+      let right = this._start
+      const currentAttributes = new Map()
+      for (let i = 0; i < delta.length; i++) {
+        let op = delta[i]
+        if (op.insert !== undefined) {
+          ;[left, right] = insertText(y, op.insert, this, left, right, currentAttributes, op.attributes || {})
+        } else if (op.retain !== undefined) {
+          ;[left, right] = formatText(y, op.retain, this, left, right, currentAttributes, op.attributes || {})
+        } else if (op.delete !== undefined) {
+          ;[left, right] = deleteText(y, op.delete, this, left, right, currentAttributes)
+        }
+      }
+    })
+  }
+
+  /**
+   * Returns the Delta representation of this YText type.
+   *
+   * @return {Delta} The Delta representation of this type.
+   *
+   * @public
+   */
+  toDelta () {
+    let ops = []
+    let currentAttributes = new Map()
+    let str = ''
+    let n = this._start
+    function packStr () {
+      if (str.length > 0) {
+        // pack str with attributes to ops
+        let attributes = {}
+        let addAttributes = false
+        for (let [key, value] of currentAttributes) {
+          addAttributes = true
+          attributes[key] = value
+        }
+        let op = { insert: str }
+        if (addAttributes) {
+          op.attributes = attributes
+        }
+        ops.push(op)
+        str = ''
+      }
+    }
+    while (n !== null) {
+      if (!n._deleted) {
+        switch (n.constructor) {
+          case ItemString:
+            str += n._content
+            break
+          case ItemFormat:
+            packStr()
+            updateCurrentAttributes(currentAttributes, n)
+            break
+        }
+      }
+      n = n._right
+    }
+    packStr()
+    return ops
+  }
+
+  /**
+   * Insert text at a given index.
+   *
+   * @param {Integer} index The index at which to start inserting.
+   * @param {String} text The text to insert at the specified position.
+   * @param {TextAttributes} attributes Optionally define some formatting
+   *                                    information to apply on the inserted
+   *                                    Text.
+   *
+   * @public
+   */
+  insert (index, text, attributes = {}) {
+    if (text.length <= 0) {
+      return
+    }
+    this._transact(y => {
+      let [left, right, currentAttributes] = findPosition(this, index)
+      insertText(y, text, this, left, right, currentAttributes, attributes)
+    })
+  }
+
+  /**
+   * Inserts an embed at a index.
+   *
+   * @param {Integer} index The index to insert the embed at.
+   * @param {Object} embed The Object that represents the embed.
+   * @param {TextAttributes} attributes Attribute information to apply on the
+   *                                    embed
+   *
+   * @public
+   */
+  insertEmbed (index, embed, attributes = {}) {
+    if (embed.constructor !== Object) {
+      throw new Error('Embed must be an Object')
+    }
+    this._transact(y => {
+      let [left, right, currentAttributes] = findPosition(this, index)
+      insertText(y, embed, this, left, right, currentAttributes, attributes)
+    })
+  }
+
+  /**
+   * Deletes text starting from an index.
+   *
+   * @param {Integer} index Index at which to start deleting.
+   * @param {Integer} length The number of characters to remove. Defaults to 1.
+   *
+   * @public
+   */
+  delete (index, length) {
+    if (length === 0) {
+      return
+    }
+    this._transact(y => {
+      let [left, right, currentAttributes] = findPosition(this, index)
+      deleteText(y, length, this, left, right, currentAttributes)
+    })
+  }
+
+  /**
+   * Assigns properties to a range of text.
+   *
+   * @param {Integer} index The position where to start formatting.
+   * @param {Integer} length The amount of characters to assign properties to.
+   * @param {TextAttributes} attributes Attribute information to apply on the
+   *                                    text.
+   *
+   * @public
+   */
+  format (index, length, attributes) {
+    this._transact(y => {
+      let [left, right, currentAttributes] = findPosition(this, index)
+      if (right === null) {
+        return
+      }
+      formatText(y, length, this, left, right, currentAttributes, attributes)
+    })
+  }
+  // TODO: De-duplicate code. The following code is in every type.
+  /**
+   * Transform this YText to a readable format.
+   * Useful for logging as all Items implement this method.
+   *
+   * @private
+   */
+  _logString () {
+    return logItemHelper('YText', this)
+  }
+}
--- a/src/Types/YXml/YXmlElement.mjs
+++ b/src/Types/YXml/YXmlElement.mjs
@@ -0,0 +1,190 @@
+import YMap from '../YMap/YMap.mjs'
+import YXmlFragment from './YXmlFragment.mjs'
+import { createAssociation } from '../../Bindings/DomBinding/util.mjs'
+
+/**
+ * An YXmlElement imitates the behavior of a
+ * {@link https://developer.mozilla.org/en-US/docs/Web/API/Element|Dom Element}.
+ *
+ * * An YXmlElement has attributes (key value pairs)
+ * * An YXmlElement has childElements that must inherit from YXmlElement
+ *
+ * @param {String} nodeName Node name
+ */
+export default class YXmlElement extends YXmlFragment {
+  constructor (nodeName = 'UNDEFINED') {
+    super()
+    this.nodeName = nodeName.toUpperCase()
+  }
+
+  /**
+   * @private
+   * Creates an Item with the same effect as this Item (without position effect)
+   */
+  _copy () {
+    let struct = super._copy()
+    struct.nodeName = this.nodeName
+    return struct
+  }
+
+  /**
+   * @private
+   * Read the next Item in a Decoder and fill this Item with the read data.
+   *
+   * This is called when data is received from a remote peer.
+   *
+   * @param {Y} y The Yjs instance that this Item belongs to.
+   * @param {BinaryDecoder} decoder The decoder object to read data from.
+   */
+  _fromBinary (y, decoder) {
+    const missing = super._fromBinary(y, decoder)
+    this.nodeName = decoder.readVarString()
+    return missing
+  }
+
+  /**
+   * Transform the properties of this type to binary and write it to an
+   * BinaryEncoder.
+   *
+   * This is called when this Item is sent to a remote peer.
+   *
+   * @param {BinaryEncoder} encoder The encoder to write data to.
+   *
+   * @private
+   */
+  _toBinary (encoder) {
+    super._toBinary(encoder)
+    encoder.writeVarString(this.nodeName)
+  }
+
+  /**
+   * Integrates this Item into the shared structure.
+   *
+   * This method actually applies the change to the Yjs instance. In case of
+   * Item it connects _left and _right to this Item and calls the
+   * {@link Item#beforeChange} method.
+   *
+   * * Checks for nodeName
+   * * Sets domFilter
+   *
+   * @param {Y} y The Yjs instance
+   *
+   * @private
+   */
+  _integrate (y) {
+    if (this.nodeName === null) {
+      throw new Error('nodeName must be defined!')
+    }
+    super._integrate(y)
+  }
+
+  /**
+   * Returns the string representation of this YXmlElement.
+   * The attributes are ordered by attribute-name, so you can easily use this
+   * method to compare YXmlElements
+   *
+   * @return {String} The string representation of this type.
+   *
+   * @public
+   */
+  toString () {
+    const attrs = this.getAttributes()
+    const stringBuilder = []
+    const keys = []
+    for (let key in attrs) {
+      keys.push(key)
+    }
+    keys.sort()
+    const keysLen = keys.length
+    for (let i = 0; i < keysLen; i++) {
+      const key = keys[i]
+      stringBuilder.push(key + '="' + attrs[key] + '"')
+    }
+    const nodeName = this.nodeName.toLocaleLowerCase()
+    const attrsString = stringBuilder.length > 0 ? ' ' + stringBuilder.join(' ') : ''
+    return `<${nodeName}${attrsString}>${super.toString()}</${nodeName}>`
+  }
+
+  /**
+   * Removes an attribute from this YXmlElement.
+   *
+   * @param {String} attributeName The attribute name that is to be removed.
+   *
+   * @public
+   */
+  removeAttribute (attributeName) {
+    return YMap.prototype.delete.call(this, attributeName)
+  }
+
+  /**
+   * Sets or updates an attribute.
+   *
+   * @param {String} attributeName The attribute name that is to be set.
+   * @param {String} attributeValue The attribute value that is to be set.
+   *
+   * @public
+   */
+  setAttribute (attributeName, attributeValue) {
+    return YMap.prototype.set.call(this, attributeName, attributeValue)
+  }
+
+  /**
+   * Returns an attribute value that belongs to the attribute name.
+   *
+   * @param {String} attributeName The attribute name that identifies the
+   *                               queried value.
+   * @return {String} The queried attribute value.
+   *
+   * @public
+   */
+  getAttribute (attributeName) {
+    return YMap.prototype.get.call(this, attributeName)
+  }
+
+  /**
+   * Returns all attribute name/value pairs in a JSON Object.
+   *
+   * @return {Object} A JSON Object that describes the attributes.
+   *
+   * @public
+   */
+  getAttributes () {
+    const obj = {}
+    for (let [key, value] of this._map) {
+      if (!value._deleted) {
+        obj[key] = value._content[0]
+      }
+    }
+    return obj
+  }
+  // TODO: outsource the binding property.
+  /**
+   * Creates a Dom Element that mirrors this YXmlElement.
+   *
+   * @param {Document} [_document=document] The document object (you must define
+   *                                        this when calling this method in
+   *                                        nodejs)
+   * @param {Object<key:hookDefinition>} [hooks={}] Optional property to customize how hooks
+   *                                             are presented in the DOM
+   * @param {DomBinding} [binding] You should not set this property. This is
+   *                               used if DomBinding wants to create a
+   *                               association to the created DOM type.
+   * @return {Element} The {@link https://developer.mozilla.org/en-US/docs/Web/API/Element|Dom Element}
+   *
+   * @public
+   */
+  toDom (_document = document, hooks = {}, binding) {
+    const dom = _document.createElement(this.nodeName)
+    let attrs = this.getAttributes()
+    for (let key in attrs) {
+      dom.setAttribute(key, attrs[key])
+    }
+    this.forEach(yxml => {
+      dom.appendChild(yxml.toDom(_document, hooks, binding))
+    })
+    createAssociation(binding, dom, this)
+    return dom
+  }
+}
+
+YXmlFragment._YXmlElement = YXmlElement
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Kevin Jahns	2d897f1844	add function to create lots of rooms	2018-06-07 16:36:42 +02:00
Kevin Jahns	fb2f9bc493	add client-server updateCounter support to sync all persisted rooms	2018-06-04 17:35:39 +02:00
Kevin Jahns	6f9ae0c4fc	save current state at the beginning in YIndexedDB	2018-06-03 22:39:22 +02:00
Kevin Jahns	9df20fac8a	added YIndexedDB	2018-06-03 21:58:51 +02:00
Kevin Jahns	a1fb1a6258	add persistence decoder	2018-06-02 22:16:12 +02:00
Kevin Jahns	417d0ef3b5	save state in FilePersistence	2018-06-02 13:33:04 +02:00
Kevin Jahns	9be256231b	enable gc in demo	2018-05-23 16:15:11 +02:00
Kevin Jahns	c122bdc750	BinaryEncoder writes directly to ArrayBuffer, improves memory consumption	2018-05-23 16:06:38 +02:00
Kevin Jahns	4ef36ab81c	fix tests	2018-05-23 14:16:54 +02:00
Kevin Jahns	cccc0e1015	implemented experimental websockets-connector	2018-05-23 14:01:00 +02:00
Kevin Jahns	684d38d6c8	make compatible with webpack and less sophisticated module bundlers	2018-05-13 13:07:24 +02:00
Kevin Jahns	44fa064eb2	Merge branch 'master' of github.com:y-js/yjs	2018-05-12 16:43:28 +02:00
Kevin Jahns	9b6fffd880	Add rollup dependency - closes #110	2018-05-12 16:43:05 +02:00
Kevin Jahns	e9993b2643	Merge pull request #111 from larskarbo/patch-1 (DOCS) Remove y-array duplicates	2018-05-12 16:41:14 +02:00
Kevin Jahns	762e9e8a3a	do not log _start in logItemHelper. Fixes #114	2018-05-12 15:42:31 +02:00
Kevin Jahns	6ddeb788c7	Merge branch 'master' of github.com:y-js/yjs	2018-05-09 16:28:07 +02:00
Kevin Jahns	b9245f323c	prefer !== undefined check instead of hasOwnProperty	2018-05-09 16:27:55 +02:00
Kevin Jahns	c0e630b635	prefer parentElement instead of parentNode	2018-05-09 14:42:24 +02:00
Kevin Jahns	e56457a0ef	13.0.0-60	2018-05-08 13:46:27 +02:00
Kevin Jahns	ca13849828	fix domBinding infinite loop	2018-05-08 13:45:51 +02:00
Kevin Jahns	92c2fbd6d3	remove debug dependency	2018-05-07 11:52:37 +02:00
Kevin Jahns	65b8921f05	13.0.0-59	2018-05-07 11:45:39 +02:00
Kevin Jahns	1ace7f4b73	fix parentNode binding in case parent doesn't fire MO	2018-05-07 11:44:22 +02:00
Kevin Jahns	6336064516	13.0.0-58	2018-05-05 15:33:53 +02:00
Kevin Jahns	49d2e42b41	fix missing dom-binding - still investigating	2018-05-05 15:33:16 +02:00
Kevin Jahns	c098e8e745	implement scroll-fixer	2018-05-05 14:47:59 +02:00
Kevin Jahns	38558a7fad	13.0.0-57	2018-05-02 18:42:56 +02:00
Kevin Jahns	bdb3782f8f	add option to disable gc (compatible with older versions)	2018-05-02 18:42:18 +02:00
Kevin Jahns	bc32f7348e	13.0.0-56	2018-04-27 18:43:24 +02:00
Kevin Jahns	09a94f053e	merge with master	2018-04-27 18:39:34 +02:00
Kevin Jahns	0df0079fa3	Merge branch 'master' of github.com:y-js/yjs	2018-04-27 18:33:51 +02:00
Kevin Jahns	a54d826d6d	bugfixes	2018-04-27 18:33:28 +02:00
Kevin Jahns	99f92cb9a0	fix filtering	2018-04-26 16:01:17 +02:00
Kevin Jahns	e788ad1333	fix hook binding	2018-04-26 14:07:12 +02:00
Kevin Jahns	1fe37c565e	hooks port to domBinding	2018-04-26 13:26:21 +02:00
Lars Karbo	ed2273e2ed	Remove y-array duplicates	2018-04-24 12:59:51 -07:00
Kevin Jahns	94933a704d	correctly handle gc with UndoManager and un-merge when syncing	2018-04-23 13:25:40 +02:00
Kevin Jahns	ef6eb08335	fix most gc bugs - test suite running again	2018-04-19 18:28:25 +02:00
Kevin Jahns	d915c8dd13	prelim gc	2018-04-03 13:28:24 +02:00
Kevin Jahns	32207cbca0	implement new mark deleted / gc approach	2018-03-29 16:36:34 +02:00
Kevin Jahns	135c6d31be	documentation and fix tests	2018-03-29 11:58:02 +02:00
Kevin Jahns	61149b458a	less duplicate code	2018-03-23 05:22:45 +01:00
Kevin Jahns	ba97bfdd9e	remove fundraiser campaign	2018-03-23 04:44:26 +01:00
Kevin Jahns	689bca8602	Merge remote-tracking branch 'origin' into v13-doc	2018-03-23 04:40:08 +01:00
Kevin Jahns	6dd43cde17	cleanup docs	2018-03-23 04:39:32 +01:00
Kevin Jahns	026675b438	separate dom binding	2018-03-23 01:55:47 +01:00
Kevin Jahns	941a22b257	13.0.0-55	2018-03-14 18:52:49 -07:00
Kevin Jahns	4aa41b98a9	fix dom filtering bug	2018-03-14 18:51:48 -07:00
Kevin Jahns	acf443aacb	reworking bindings	2018-03-12 03:36:37 +01:00
Kevin Jahns	aa8c934833	Add fundraiser campaign	2018-03-06 05:27:03 +01:00
Kevin Jahns	814af5a3d7	fix import locations	2018-03-06 05:22:18 +01:00
Kevin Jahns	bbc207aaa6	restructer and move to esdoc	2018-03-06 03:17:50 +01:00
Kevin Jahns	a9b610479d	big documentation update - all public functions and classes are documented now	2018-03-05 03:12:04 +01:00
Kevin Jahns	079de07eff	13.0.0-54	2018-03-01 16:45:25 +01:00
Kevin Jahns	54453e87fa	fix consecutive undo,redo,undo,redo.. (abc test)	2018-03-01 16:44:26 +01:00
Kevin Jahns	1b0e3659c3	undo fixes for consecutive undo-redo	2018-03-01 13:50:01 +01:00
Kevin Jahns	dc22a79ac4	properly unregister event when binding is destroyed	2018-02-27 03:52:40 +01:00
Kevin Jahns	384a4b72b0	add quill-cursors example	2018-02-26 17:24:28 +01:00
Kevin Jahns	f35c056bde	fix some tests	2018-02-26 03:23:22 +01:00
Kevin Jahns	250050e83b	Merge remote-tracking branch 'origin' into y-richtext-rewrite	2018-02-26 02:19:08 +01:00
Kevin Jahns	248d08be30	implement quill binding for y-text	2018-02-26 02:18:39 +01:00
Kevin Jahns	641f426339	13.0.0-53	2018-02-25 02:31:59 +01:00
Kevin Jahns	fcbca65d8f	fromBinary is a transaction	2018-02-25 02:31:20 +01:00
Kevin Jahns	5f8ae0dd43	13.0.0-52	2018-02-18 19:20:00 +01:00
Kevin Jahns	de14fe0f3e	fix getAttribute vs attributes.value fixes y-js/y-xml#8	2018-02-18 18:58:49 +01:00
Kevin Jahns	5e4b071693	actually use clock in undo-manager	2018-02-15 18:58:43 +01:00
Kevin Jahns	937de2c59f	fix fast undo-redo bug	2018-02-15 18:28:53 +01:00
Kevin Jahns	f1f1bff901	preliminary undo-redo fixes	2018-02-15 17:58:14 +01:00
Kevin Jahns	da748a78f4	start rewriting y-richtext	2018-02-15 01:25:08 +01:00
Kevin Jahns	4855b2d590	13.0.0-51	2018-02-07 14:08:43 +01:00
Kevin Jahns	908ce31e2f	Merge branch 'master' of github.com:y-js/yjs	2018-02-07 14:08:07 +01:00
Kevin Jahns	e4d4c23f0b	bugfix - persist deletes when syncing	2018-02-07 14:07:57 +01:00
Kevin Jahns	fc500a8247	Merge pull request #94 from LukasDrgon/patch-3 Add CDN usage	2018-01-31 20:36:26 -08:00
Kevin Jahns	4b84541d76	13.0.0-50	2018-01-30 20:12:58 -08:00
Kevin Jahns	a3ab42c157	implemnt mutual exclude pattern directly in Persistence.js	2018-01-30 20:11:59 -08:00
Kevin Jahns	bbd3317d62	13.0.0-49	2018-01-30 15:53:33 -08:00
Kevin Jahns	5d3922cb64	fix undo-redo	2018-01-30 15:52:36 -08:00
Kevin Jahns	a81a2cd553	13.0.0-48	2018-01-29 16:41:52 -08:00
Kevin Jahns	c0d24bdba4	lint	2018-01-29 16:41:27 -08:00
Kevin Jahns	40e913e9c5	add toBinary and fromBinary to Y.utils	2018-01-29 16:39:09 -08:00
Kevin Jahns	94f6a0fd9c	implement Y.*Binding approach	2018-01-29 11:55:28 -08:00
Kevin Jahns	41a88dbc43	fix examples for Yjs@13	2018-01-25 17:28:33 -07:00
Kevin Jahns	1d4f283955	13.0.0-47	2018-01-18 18:44:56 +01:00
Kevin Jahns	fc3a4c376c	implement when-handler	2018-01-18 18:44:20 +01:00
Lukas Drgon	acb0affa33	Add CDN usage	2018-01-17 22:03:49 +01:00
Kevin Jahns	0b510b64a3	persistence updates + make Persistence.init async	2018-01-16 16:13:47 +01:00
Kevin Jahns	c8f0cf5556	13.0.0-46	2018-01-10 00:20:03 +01:00
Kevin Jahns	11a4271fd1	13.0.0-45	2018-01-10 00:18:50 +01:00
Kevin Jahns	c7670915c7	Merge branch 'master' of github.com:y-js/yjs	2018-01-10 00:17:34 +01:00
Kevin Jahns	eb2d596538	implement mutualExclude factory	2018-01-10 00:17:26 +01:00
Kevin Jahns	48e17ea1a7	13.0.0-44	2018-01-10 00:16:33 +01:00
Kevin Jahns	1a22fdd45e	persistence improvements	2018-01-10 00:11:25 +01:00
Kevin Jahns	07cf0b3436	export AbstractPersistence	2018-01-08 17:30:30 +01:00
Kevin Jahns	5a68b9f4ad	loaded event when loaded from persistence adapter	2018-01-08 02:28:46 +01:00
Kevin Jahns	445dd3e0da	fix several y-xml bugs	2018-01-03 03:50:27 +01:00
Kevin Jahns	0ba97d78f8	better relative cursor positions for text editing - decrease number of generated messages for cursor	2017-12-31 16:14:02 +01:00
Kevin Jahns	fc5be5c7cc	fix empty string insertion bug	2017-12-31 14:49:20 +01:00
Kevin Jahns	f2debc150c	reimplement persistence approach	2017-12-24 03:18:00 +01:00
Kevin Jahns	08f37a86e3	13.0.0-43	2017-12-21 16:06:29 +01:00
Kevin Jahns	f5d17e6236	filter y-xml when domFilter is set	2017-12-21 16:05:50 +01:00
Kevin Jahns	8f3bd7170a	13.0.0-42	2017-12-19 17:39:01 +01:00
Kevin Jahns	5586334549	fix initial content in y-array	2017-12-19 17:37:04 +01:00
Kevin Jahns	24c1e4dcc8	13.0.0-41	2017-12-14 14:30:02 +01:00
Kevin Jahns	d61bbecf4e	fix tree walker on YXmlFragment	2017-12-14 14:29:16 +01:00
Kevin Jahns	85492ad2e0	fix drawing example. Add drawing hook for y-xml	2017-12-13 12:49:34 +01:00
Kevin Jahns	02253f9a8d	fix log outputs	2017-12-13 10:28:19 +01:00
Kevin Jahns	8105bef1af	work on drawing demo	2017-12-06 19:20:52 -08:00
Kevin Jahns	4efa16e2dd	13.0.0-40	2017-12-05 21:50:34 -08:00
Kevin Jahns	ad44f59def	implement new dom update algorithm	2017-12-05 21:50:00 -08:00
Kevin Jahns	9c471ea24d	13.0.0-39	2017-12-05 17:06:01 -08:00
Kevin Jahns	d9e76014f5	fix remaining cursor relocation issues	2017-12-05 17:05:12 -08:00
Kevin Jahns	4091b7d004	13.0.0-38	2017-12-05 00:53:25 -08:00
Kevin Jahns	dfc183643d	support data-yjs-hook attribute for yjs hooks	2017-12-05 00:52:52 -08:00
Kevin Jahns	cf8698f2b6	13.0.0-37	2017-12-02 01:45:55 -08:00
Kevin Jahns	3595f14da7	fix insert in y-text	2017-12-02 01:45:22 -08:00
Kevin Jahns	c6e671b1d5	13.0.0-36	2017-11-30 18:39:17 -08:00
Kevin Jahns	e4c10fd6b3	handle xmlhook in mutation observer	2017-11-30 18:38:12 -08:00
Kevin Jahns	e70aa09f88	Implement YXml element hooks (based on _yjsHook property)	2017-11-29 17:16:06 -08:00
Kevin Jahns	7808b143da	13.0.0-35	2017-11-28 17:38:31 -08:00
Kevin Jahns	b35092928e	fix user selection issues	2017-11-28 17:37:15 -08:00
				`@@ -0,0 +1,2 @@`

				`export default class AbstractPersistence {}`