large scale refactoring

bindings/dom/DomBinding.js

@@ -0,0 +1,248 @@
+/**
+ * @module bindings/dom
+ */
+
+/* global MutationObserver, getSelection */
+
+import { fromRelativePosition } from '../../utils/relativePosition.js'
+import { createMutex } from '../../lib/mutex.js'
+import { createAssociation, removeAssociation } from './util.js'
+import { beforeTransactionSelectionFixer, afterTransactionSelectionFixer, getCurrentRelativeSelection } from './selection.js'
+import { defaultFilter, applyFilterOnType } from './filter.js'
+import { typeObserver } from './typeObserver.js'
+import { domObserver } from './domObserver.js'
+import { YXmlFragment } from '../../types/YXmlElement.js' // eslint-disable-line
+
+/**
+ * @callback DomFilter
+ * @param {string} nodeName
+ * @param {Map<string, string>} attrs
+ * @return {Map | null}
+ */
+
+/**
+ * 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)
+ *
+ * @class
+ */
+export class DomBinding {
+  /**
+   * @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 {DomFilter} [opts.filter=defaultFilter] The filter function to use.
+   * @param {Document} [opts.document=document] The filter function to use.
+   * @param {Object} [opts.hooks] The filter function to use.
+   * @param {Element} [opts.scrollingElement=null] The filter function to use.
+   */
+  constructor (type, target, opts = {}) {
+    // Binding handles textType as this.type and domTextarea as this.target
+    /**
+     * The Yjs type that is bound to `target`
+     * @type {YXmlFragment}
+     */
+    this.type = type
+    /**
+     * The target that `type` is bound to.
+     * @type {Element}
+     */
+    this.target = target
+    /**
+     * @private
+     */
+    this._mutualExclude = createMutex()
+    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 {DomFilter}
+     */
+    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
+    })
+    this._currentSel = null
+    this._selectionchange = () => {
+      this._currentSel = getCurrentRelativeSelection(this)
+    }
+    document.addEventListener('selectionchange', this._selectionchange)
+    const y = type._y
+    this.y = y
+    // Force flush dom changes before Type changes are applied (they might
+    // modify the dom)
+    this._beforeTransactionHandler = y => {
+      this._domObserver(this._mutationObserver.takeRecords())
+      this._mutualExclude(() => {
+        beforeTransactionSelectionFixer(this)
+      })
+    }
+    y.on('beforeTransaction', this._beforeTransactionHandler)
+    this._afterTransactionHandler = (y, transaction) => {
+      this._mutualExclude(() => {
+        afterTransactionSelectionFixer(this)
+      })
+      // 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)
+  }
+
+  flushDomChanges () {
+    this._domObserver(this._mutationObserver.takeRecords())
+  }
+
+  /**
+   * NOTE:
+   * * does not apply filter to existing elements!
+   * * only guarantees that changes are filtered locally. Remote sites may see different content.
+   *
+   * @param {DomFilter} filter The filter function to use from now on.
+   */
+  setFilter (filter) {
+    this.filter = filter
+    // TODO: apply filter to all elements
+  }
+
+  _getUndoStackInfo () {
+    return this.getSelection()
+  }
+
+  _restoreUndoStackInfo (info) {
+    this.restoreSelection(info)
+  }
+
+  getSelection () {
+    return this._currentSel
+  }
+
+  restoreSelection (selection) {
+    if (selection !== null) {
+      const { to, from } = selection
+      /**
+       * There is little information on the difference between anchor/focus and base/extent.
+       * MDN doesn't even mention base/extent anymore.. though you still have to call
+       * setBaseAndExtent to change the selection..
+       * I can observe that base/extend refer to notes higher up in the xml hierachy.
+       * Espesially for undo/redo this is preferred. If this becomes a problem in the future,
+       * we should probably go back to anchor/focus.
+       */
+      const browserSelection = getSelection()
+      let { baseNode, baseOffset, extentNode, extentOffset } = browserSelection
+      if (from !== null) {
+        let sel = fromRelativePosition(this.y, from)
+        if (sel !== null) {
+          let node = this.typeToDom.get(sel.type)
+          let offset = sel.offset
+          if (node !== baseNode || offset !== baseOffset) {
+            baseNode = node
+            baseOffset = offset
+          }
+        }
+      }
+      if (to !== null) {
+        let sel = fromRelativePosition(this.y, to)
+        if (sel !== null) {
+          let node = this.typeToDom.get(sel.type)
+          let offset = sel.offset
+          if (node !== extentNode || offset !== extentOffset) {
+            extentNode = node
+            extentOffset = offset
+          }
+        }
+      }
+      browserSelection.setBaseAndExtent(
+        baseNode,
+        baseOffset,
+        extentNode,
+        extentOffset
+      )
+    }
+  }
+
+  /**
+   * 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)
+    document.removeEventListener('selectionchange', this._selectionchange)
+    this.type = null
+    this.target = null
+  }
+}
+
+/**
+ * A filter defines which elements and attributes to share.
+ * Return null if the node should be filtered. Otherwise return the Map of
+ * accepted attributes.
+ *
+ * @callback FilterFunction
+ * @param {string} nodeName
+ * @param {Map} attrs
+ * @return {Map|null}
+ */

bindings/dom/domObserver.js

@@ -0,0 +1,147 @@
+/**
+ * @module bindings/dom
+ */
+
+import { YXmlHook } from '../../types/YXmlHook.js'
+import {
+  iterateUntilUndeleted,
+  removeAssociation,
+  insertNodeHelper } from './util.js'
+import { simpleDiff } from '../../lib/diff.js'
+import { YXmlFragment } from '../../types/YXmlElement.js'
+
+/**
+ * 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
+ */
+const 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(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 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 = simpleDiff(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)
+      }
+    })
+  })
+}

bindings/dom/domToType.js

@@ -0,0 +1,73 @@
+/**
+ * @module bindings/dom
+ */
+
+/* eslint-env browser */
+import { YXmlText } from '../../types/YXmlText.js'
+import { YXmlHook } from '../../types/YXmlHook.js'
+import { YXmlElement } from '../../types/YXmlElement.js'
+import { createAssociation, domsToTypes } from './util.js'
+import { filterDomAttributes, defaultFilter } from './filter.js'
+import { DomBinding } from './DomBinding.js' // eslint-disable-line
+
+/**
+ * @callback DomFilter
+ * @param {string} nodeName
+ * @param {Map<string, string>} attrs
+ * @return {Map | null}
+ */
+
+/**
+ * Creates a Yjs type (YXml) based on the contents of a DOM Element.
+ *
+ * @param {Element|Text} element The DOM Element
+ * @param {?Document} _document Optional. Provide the global document object
+ * @param {Object<string, any>} [hooks = {}] Optional. Set of Yjs Hooks
+ * @param {DomFilter} [filter=defaultFilter] Optional. Dom element filter
+ * @param {?DomBinding} binding Warning: This property is for internal use only!
+ * @return {YXmlElement | YXmlText | false}
+ */
+export const domToType = (element, _document = document, hooks = {}, filter = defaultFilter, binding) => {
+  /**
+   * @type {any}
+   */
+  let type = null
+  if (element instanceof Element) {
+    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.`)
+        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)
+    }
+  } else if (element instanceof Text) {
+    type = new YXmlText()
+    type.insert(0, element.nodeValue)
+  } else {
+    throw new Error('Can\'t transform this node type to a YXml type!')
+  }
+  createAssociation(binding, element, type)
+  return type
+}

bindings/dom/filter.js

@@ -0,0 +1,66 @@
+/**
+ * @module bindings/dom
+ */
+
+import { isParentOf } from '../../utils/isParentOf.js'
+import * as Y from '../../index.js'
+import { DomBinding } from './DomBinding.js' // eslint-disable-line
+
+/**
+ * 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 const defaultFilter = (nodeName, attrs) => {
+  // TODO: implement basic filter that filters out dangerous properties!
+  return attrs
+}
+
+/**
+ *
+ */
+export const 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} y The Yjs instance.
+ * @param {DomBinding} binding The DOM binding instance that has the dom filter.
+ * @param {Y.XmlElement | Y.XmlFragment } type The type to apply the filter to.
+ *
+ * @private
+ */
+export const applyFilterOnType = (y, binding, type) => {
+  if (isParentOf(binding.type, type) && type instanceof Y.XmlElement) {
+    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, true)
+    } else {
+      // iterate original attributes
+      attributes.forEach((value, key) => {
+        // delete all attributes that are not in filteredAttributes
+        if (filteredAttributes.has(key) === false) {
+          type.removeAttribute(key)
+        }
+      })
+    }
+  }
+}

bindings/dom/selection.js

@@ -0,0 +1,39 @@
+/**
+ * @module bindings/dom
+ */
+
+/* globals getSelection */
+
+import { getRelativePosition } from '../../utils/relativePosition.js'
+
+let relativeSelection = null
+
+const _getCurrentRelativeSelection = domBinding => {
+  const { baseNode, baseOffset, extentNode, extentOffset } = getSelection()
+  const baseNodeType = domBinding.domToType.get(baseNode)
+  const extentNodeType = domBinding.domToType.get(extentNode)
+  if (baseNodeType !== undefined && extentNodeType !== undefined) {
+    return {
+      from: getRelativePosition(baseNodeType, baseOffset),
+      to: getRelativePosition(extentNodeType, extentOffset)
+    }
+  }
+  return null
+}
+
+export const getCurrentRelativeSelection = typeof getSelection !== 'undefined' ? _getCurrentRelativeSelection : domBinding => null
+
+export const beforeTransactionSelectionFixer = domBinding => {
+  relativeSelection = getCurrentRelativeSelection(domBinding)
+}
+
+/**
+ * Reset the browser range after every transaction.
+ * This prevents any collapsing issues with the local selection.
+ * @private
+ */
+export const afterTransactionSelectionFixer = domBinding => {
+  if (relativeSelection !== null) {
+    domBinding.restoreSelection(relativeSelection)
+  }
+}

bindings/dom/typeObserver.js

@@ -0,0 +1,110 @@
+/**
+ * @module bindings/dom
+ */
+
+/* eslint-env browser */
+/* global getSelection */
+
+import { YXmlText } from '../../types/YXmlText.js'
+import { YXmlHook } from '../../types/YXmlHook.js'
+import { removeDomChildrenUntilElementFound } from './util.js'
+
+const 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 {
+      /**
+       * @type {Element}
+       */
+      let elem = anchor.parentElement
+      if (anchor instanceof Element) {
+        elem = anchor
+      }
+      return {
+        elem,
+        top: elem.getBoundingClientRect().top
+      }
+    }
+  }
+  return null
+}
+
+const 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 const typeObserver = function (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)
+  })
+}

bindings/dom/util.js

@@ -0,0 +1,132 @@
+/**
+ * @module bindings/dom
+ */
+
+import { domToType } from './domToType.js'
+import { DomBinding } from './DomBinding.js' // eslint-disable-line
+import { YXmlHook } from '../../types/YXmlHook.js' // eslint-disable-line
+import { YXmlText } from '../../types/YXmlText.js' // eslint-disable-line
+import { YXmlElement, YXmlFragment } from '../../types/YXmlElement.js' // eslint-disable-line
+
+/**
+ * Iterates items until an undeleted item is found.
+ *
+ * @private
+ */
+export const 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).
+ *
+ * @private
+ * @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 const 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).
+ *
+ * @private
+ * @param {DomBinding} domBinding The binding object
+ * @param {DocumentFragment|Element|Text} dom The dom that is to be associated with type
+ * @param {YXmlFragment|YXmlElement|YXmlHook|YXmlText} type The type that is to be associated with dom
+ *
+ */
+export const 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.
+ *
+ * @private
+ * @param {DomBinding} domBinding The binding object
+ * @param {Element} oldDom The existing dom
+ * @param {Element} newDom The new dom object
+ */
+export const 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.
+ *
+ * @private
+ * @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.
+ */
+export const insertDomElementsAfter = (type, prev, doms, _document, binding) => {
+  const types = domsToTypes(doms, _document, binding.opts.hooks, binding.filter, binding)
+  return type.insertAfter(prev, types)
+}
+
+export const 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 const 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.
+ *
+ * @private
+ * @param {Element} parent The parent of `elem` and `currentChild`.
+ * @param {Node} currentChild Start removing elements with `currentChild`. If
+ *                               `currentChild` is `elem` it won't be removed.
+ * @param {Element|null} elem The elemnt to look for.
+ */
+export const removeDomChildrenUntilElementFound = (parent, currentChild, elem) => {
+  while (currentChild !== elem) {
+    const del = currentChild
+    currentChild = currentChild.nextSibling
+    parent.removeChild(del)
+  }
+}