`.\n\t * Second colon and everything after will be cut. Passing event name is a safe and good practice.\n\t * @returns {null|Boolean} `null` if such consumable was never added, `false` if the consumable values was\n\t * already consumed or `true` if it was added and not consumed yet.\n\t */\n\ttest( item, type ) {\n\t\ttype = _normalizeConsumableType( type );\n\n\t\tif ( item instanceof TextProxy ) {\n\t\t\titem = this._getSymbolForTextProxy( item );\n\t\t}\n\n\t\tconst itemConsumables = this._consumable.get( item );\n\n\t\tif ( itemConsumables === undefined ) {\n\t\t\treturn null;\n\t\t}\n\n\t\tconst value = itemConsumables.get( type );\n\n\t\tif ( value === undefined ) {\n\t\t\treturn null;\n\t\t}\n\n\t\treturn value;\n\t}\n\n\t/**\n\t * Reverts consuming of consumable value.\n\t *\n\t *\t\tmodelConsumable.revert( modelElement, 'insert' ); // Revert consuming `modelElement` insertion change.\n\t *\t\tmodelConsumable.revert( modelElement, 'addAttribute:bold' ); // Revert consuming `bold` attribute insert from `modelElement`.\n\t *\t\tmodelConsumable.revert( modelElement, 'removeAttribute:bold' ); // Revert consuming `bold` attribute remove from `modelElement`.\n\t *\t\tmodelConsumable.revert( modelSelection, 'selection' ); // Revert consuming `modelSelection`.\n\t *\t\tmodelConsumable.revert( modelRange, 'range' ); // Revert consuming `modelRange`.\n\t *\n\t * @param {module:engine/model/item~Item|module:engine/model/selection~Selection|module:engine/model/range~Range} item\n\t * Model item, range or selection to be reverted.\n\t * @param {String} type Consumable type.\n\t * @returns {null|Boolean} `true` if consumable has been reversed, `false` otherwise. `null` if the consumable has\n\t * never been added.\n\t */\n\trevert( item, type ) {\n\t\ttype = _normalizeConsumableType( type );\n\n\t\tif ( item instanceof TextProxy ) {\n\t\t\titem = this._getSymbolForTextProxy( item );\n\t\t}\n\n\t\tconst test = this.test( item, type );\n\n\t\tif ( test === false ) {\n\t\t\tthis._consumable.get( item ).set( type, true );\n\n\t\t\treturn true;\n\t\t} else if ( test === true ) {\n\t\t\treturn false;\n\t\t}\n\n\t\treturn null;\n\t}\n\n\t/**\n\t * Gets a unique symbol for passed {@link module:engine/model/textproxy~TextProxy} instance. All `TextProxy` instances that\n\t * have same parent, same start index and same end index will get the same symbol.\n\t *\n\t * Used internally to correctly consume `TextProxy` instances.\n\t *\n\t * @private\n\t * @param {module:engine/model/textproxy~TextProxy} textProxy `TextProxy` instance to get a symbol for.\n\t * @returns {Symbol} Symbol representing all equal instances of `TextProxy`.\n\t */\n\t_getSymbolForTextProxy( textProxy ) {\n\t\tlet symbol = null;\n\n\t\tconst startMap = this._textProxyRegistry.get( textProxy.startOffset );\n\n\t\tif ( startMap ) {\n\t\t\tconst endMap = startMap.get( textProxy.endOffset );\n\n\t\t\tif ( endMap ) {\n\t\t\t\tsymbol = endMap.get( textProxy.parent );\n\t\t\t}\n\t\t}\n\n\t\tif ( !symbol ) {\n\t\t\tsymbol = this._addSymbolForTextProxy( textProxy.startOffset, textProxy.endOffset, textProxy.parent );\n\t\t}\n\n\t\treturn symbol;\n\t}\n\n\t/**\n\t * Adds a symbol for given properties that characterizes a {@link module:engine/model/textproxy~TextProxy} instance.\n\t *\n\t * Used internally to correctly consume `TextProxy` instances.\n\t *\n\t * @private\n\t * @param {Number} startIndex Text proxy start index in it's parent.\n\t * @param {Number} endIndex Text proxy end index in it's parent.\n\t * @param {module:engine/model/element~Element} parent Text proxy parent.\n\t * @returns {Symbol} Symbol generated for given properties.\n\t */\n\t_addSymbolForTextProxy( start, end, parent ) {\n\t\tconst symbol = Symbol( 'textProxySymbol' );\n\t\tlet startMap, endMap;\n\n\t\tstartMap = this._textProxyRegistry.get( start );\n\n\t\tif ( !startMap ) {\n\t\t\tstartMap = new Map();\n\t\t\tthis._textProxyRegistry.set( start, startMap );\n\t\t}\n\n\t\tendMap = startMap.get( end );\n\n\t\tif ( !endMap ) {\n\t\t\tendMap = new Map();\n\t\t\tstartMap.set( end, endMap );\n\t\t}\n\n\t\tendMap.set( parent, symbol );\n\n\t\treturn symbol;\n\t}\n}\n\n// Returns a normalized consumable type name from given string. A normalized consumable type name is a string that has\n// at most one colon, for example: `insert` or `addMarker:highlight`. If string to normalize has more \"parts\" (more colons),\n// the other parts are dropped, for example: `addattribute:bold:$text` -> `addattributes:bold`.\n//\n// @param {String} type Consumable type.\n// @returns {String} Normalized consumable type.\nfunction _normalizeConsumableType( type ) {\n\tconst parts = type.split( ':' );\n\n\treturn parts.length > 1 ? parts[ 0 ] + ':' + parts[ 1 ] : parts[ 0 ];\n}\n","/**\n * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.\n * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license\n */\n\n/**\n * @module engine/conversion/downcastdispatcher\n */\n\nimport Consumable from './modelconsumable';\nimport Range from '../model/range';\nimport EmitterMixin from '@ckeditor/ckeditor5-utils/src/emittermixin';\nimport mix from '@ckeditor/ckeditor5-utils/src/mix';\nimport { extend } from 'lodash-es';\n\n/**\n * `DowncastDispatcher` is a central point of downcasting (conversion from model to view), which is a process of reacting to changes\n * in the model and firing a set of events. Callbacks listening to those events are called converters. Those\n * converters role is to convert the model changes to changes in view (for example, adding view nodes or\n * changing attributes on view elements).\n *\n * During conversion process, `DowncastDispatcher` fires events, basing on state of the model and prepares\n * data for those events. It is important to understand that those events are connected with changes done on model,\n * for example: \"node has been inserted\" or \"attribute has changed\". This is in a contrary to upcasting (view to model conversion),\n * where we convert view state (view nodes) to a model tree.\n *\n * The events are prepared basing on a diff created by {@link module:engine/model/differ~Differ Differ}, which buffers them\n * and then passes to `DowncastDispatcher` as a diff between old model state and new model state.\n *\n * Note, that because changes are converted there is a need to have a mapping between model structure and view structure.\n * To map positions and elements during downcast (model to view conversion) use {@link module:engine/conversion/mapper~Mapper}.\n *\n * `DowncastDispatcher` fires following events for model tree changes:\n *\n * * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:insert insert}\n * if a range of nodes has been inserted to the model tree,\n * * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:remove remove}\n * if a range of nodes has been removed from the model tree,\n * * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:attribute attribute}\n * if attribute has been added, changed or removed from a model node.\n *\n * For {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:insert insert}\n * and {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:attribute attribute},\n * `DowncastDispatcher` generates {@link module:engine/conversion/modelconsumable~ModelConsumable consumables}.\n * These are used to have a control over which changes has been already consumed. It is useful when some converters\n * overwrite other or converts multiple changes (for example converts insertion of an element and also converts that\n * element's attributes during insertion).\n *\n * Additionally, `DowncastDispatcher` fires events for {@link module:engine/model/markercollection~Marker marker} changes:\n *\n * * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:addMarker} if a marker has been added,\n * * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:removeMarker} if a marker has been removed.\n *\n * Note, that changing a marker is done through removing the marker from the old range, and adding on the new range,\n * so both those events are fired.\n *\n * Finally, `DowncastDispatcher` also handles firing events for {@link module:engine/model/selection model selection}\n * conversion:\n *\n * * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:selection}\n * which converts selection from model to view,\n * * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:attribute}\n * which is fired for every selection attribute,\n * * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:addMarker}\n * which is fired for every marker which contains selection.\n *\n * Unlike model tree and markers, events for selection are not fired for changes but for selection state.\n *\n * When providing custom listeners for `DowncastDispatcher` remember to check whether given change has not been\n * {@link module:engine/conversion/modelconsumable~ModelConsumable#consume consumed} yet.\n *\n * When providing custom listeners for `DowncastDispatcher` keep in mind that any callback that had\n * {@link module:engine/conversion/modelconsumable~ModelConsumable#consume consumed} a value from a consumable and\n * converted the change should also stop the event (for efficiency purposes).\n *\n * When providing custom listeners for `DowncastDispatcher` remember to use provided\n * {@link module:engine/view/downcastwriter~DowncastWriter view downcast writer} to apply changes to the view document.\n *\n * Example of a custom converter for `DowncastDispatcher`:\n *\n *\t\t// We will convert inserting \"paragraph\" model element into the model.\n *\t\tdowncastDispatcher.on( 'insert:paragraph', ( evt, data, conversionApi ) => {\n *\t\t\t// Remember to check whether the change has not been consumed yet and consume it.\n *\t\t\tif ( conversionApi.consumable.consume( data.item, 'insert' ) ) {\n *\t\t\t\treturn;\n *\t\t\t}\n *\n *\t\t\t// Translate position in model to position in view.\n *\t\t\tconst viewPosition = conversionApi.mapper.toViewPosition( data.range.start );\n *\n *\t\t\t// Create element that will be inserted in view at `viewPosition`.\n *\t\t\tconst viewElement = conversionApi.writer.createContainerElement( 'p' );\n *\n *\t\t\t// Bind the newly created view element to model element so positions will map accordingly in future.\n *\t\t\tconversionApi.mapper.bindElements( data.item, viewElement );\n *\n *\t\t\t// Add the newly created view element to the view.\n *\t\t\tconversionApi.writer.insert( viewPosition, viewElement );\n *\n *\t\t\t// Remember to stop the event propagation.\n *\t\t\tevt.stop();\n *\t\t} );\n */\nexport default class DowncastDispatcher {\n\t/**\n\t * Creates a `DowncastDispatcher` instance.\n\t *\n\t * @see module:engine/conversion/downcastdispatcher~DowncastConversionApi\n\t * @param {Object} conversionApi Additional properties for interface that will be passed to events fired\n\t * by `DowncastDispatcher`.\n\t */\n\tconstructor( conversionApi ) {\n\t\t/**\n\t\t * Interface passed by dispatcher to the events callbacks.\n\t\t *\n\t\t * @member {module:engine/conversion/downcastdispatcher~DowncastConversionApi}\n\t\t */\n\t\tthis.conversionApi = extend( { dispatcher: this }, conversionApi );\n\t}\n\n\t/**\n\t * Takes {@link module:engine/model/differ~Differ model differ} object with buffered changes and fires conversion basing on it.\n\t *\n\t * @param {module:engine/model/differ~Differ} differ Differ object with buffered changes.\n\t * @param {module:engine/model/markercollection~MarkerCollection} markers Markers connected with converted model.\n\t * @param {module:engine/view/downcastwriter~DowncastWriter} writer View writer that should be used to modify view document.\n\t */\n\tconvertChanges( differ, markers, writer ) {\n\t\t// Before the view is updated, remove markers which have changed.\n\t\tfor ( const change of differ.getMarkersToRemove() ) {\n\t\t\tthis.convertMarkerRemove( change.name, change.range, writer );\n\t\t}\n\n\t\t// Convert changes that happened on model tree.\n\t\tfor ( const entry of differ.getChanges() ) {\n\t\t\tif ( entry.type == 'insert' ) {\n\t\t\t\tthis.convertInsert( Range._createFromPositionAndShift( entry.position, entry.length ), writer );\n\t\t\t} else if ( entry.type == 'remove' ) {\n\t\t\t\tthis.convertRemove( entry.position, entry.length, entry.name, writer );\n\t\t\t} else {\n\t\t\t\t// entry.type == 'attribute'.\n\t\t\t\tthis.convertAttribute( entry.range, entry.attributeKey, entry.attributeOldValue, entry.attributeNewValue, writer );\n\t\t\t}\n\t\t}\n\n\t\tfor ( const markerName of this.conversionApi.mapper.flushUnboundMarkerNames() ) {\n\t\t\tconst markerRange = markers.get( markerName ).getRange();\n\n\t\t\tthis.convertMarkerRemove( markerName, markerRange, writer );\n\t\t\tthis.convertMarkerAdd( markerName, markerRange, writer );\n\t\t}\n\n\t\t// After the view is updated, convert markers which have changed.\n\t\tfor ( const change of differ.getMarkersToAdd() ) {\n\t\t\tthis.convertMarkerAdd( change.name, change.range, writer );\n\t\t}\n\t}\n\n\t/**\n\t * Starts conversion of a range insertion.\n\t *\n\t * For each node in the range, {@link #event:insert insert event is fired}. For each attribute on each node,\n\t * {@link #event:attribute attribute event is fired}.\n\t *\n\t * @fires insert\n\t * @fires attribute\n\t * @param {module:engine/model/range~Range} range Inserted range.\n\t * @param {module:engine/view/downcastwriter~DowncastWriter} writer View writer that should be used to modify view document.\n\t */\n\tconvertInsert( range, writer ) {\n\t\tthis.conversionApi.writer = writer;\n\n\t\t// Create a list of things that can be consumed, consisting of nodes and their attributes.\n\t\tthis.conversionApi.consumable = this._createInsertConsumable( range );\n\n\t\t// Fire a separate insert event for each node and text fragment contained in the range.\n\t\tfor ( const value of range ) {\n\t\t\tconst item = value.item;\n\t\t\tconst itemRange = Range._createFromPositionAndShift( value.previousPosition, value.length );\n\t\t\tconst data = {\n\t\t\t\titem,\n\t\t\t\trange: itemRange\n\t\t\t};\n\n\t\t\tthis._testAndFire( 'insert', data );\n\n\t\t\t// Fire a separate addAttribute event for each attribute that was set on inserted items.\n\t\t\t// This is important because most attributes converters will listen only to add/change/removeAttribute events.\n\t\t\t// If we would not add this part, attributes on inserted nodes would not be converted.\n\t\t\tfor ( const key of item.getAttributeKeys() ) {\n\t\t\t\tdata.attributeKey = key;\n\t\t\t\tdata.attributeOldValue = null;\n\t\t\t\tdata.attributeNewValue = item.getAttribute( key );\n\n\t\t\t\tthis._testAndFire( `attribute:${ key }`, data );\n\t\t\t}\n\t\t}\n\n\t\tthis._clearConversionApi();\n\t}\n\n\t/**\n\t * Fires conversion of a single node removal. Fires {@link #event:remove remove event} with provided data.\n\t *\n\t * @param {module:engine/model/position~Position} position Position from which node was removed.\n\t * @param {Number} length Offset size of removed node.\n\t * @param {String} name Name of removed node.\n\t * @param {module:engine/view/downcastwriter~DowncastWriter} writer View writer that should be used to modify view document.\n\t */\n\tconvertRemove( position, length, name, writer ) {\n\t\tthis.conversionApi.writer = writer;\n\n\t\tthis.fire( 'remove:' + name, { position, length }, this.conversionApi );\n\n\t\tthis._clearConversionApi();\n\t}\n\n\t/**\n\t * Starts conversion of attribute change on given `range`.\n\t *\n\t * For each node in the given `range`, {@link #event:attribute attribute event} is fired with the passed data.\n\t *\n\t * @fires attribute\n\t * @param {module:engine/model/range~Range} range Changed range.\n\t * @param {String} key Key of the attribute that has changed.\n\t * @param {*} oldValue Attribute value before the change or `null` if the attribute has not been set before.\n\t * @param {*} newValue New attribute value or `null` if the attribute has been removed.\n\t * @param {module:engine/view/downcastwriter~DowncastWriter} writer View writer that should be used to modify view document.\n\t */\n\tconvertAttribute( range, key, oldValue, newValue, writer ) {\n\t\tthis.conversionApi.writer = writer;\n\n\t\t// Create a list with attributes to consume.\n\t\tthis.conversionApi.consumable = this._createConsumableForRange( range, `attribute:${ key }` );\n\n\t\t// Create a separate attribute event for each node in the range.\n\t\tfor ( const value of range ) {\n\t\t\tconst item = value.item;\n\t\t\tconst itemRange = Range._createFromPositionAndShift( value.previousPosition, value.length );\n\t\t\tconst data = {\n\t\t\t\titem,\n\t\t\t\trange: itemRange,\n\t\t\t\tattributeKey: key,\n\t\t\t\tattributeOldValue: oldValue,\n\t\t\t\tattributeNewValue: newValue\n\t\t\t};\n\n\t\t\tthis._testAndFire( `attribute:${ key }`, data );\n\t\t}\n\n\t\tthis._clearConversionApi();\n\t}\n\n\t/**\n\t * Starts model selection conversion.\n\t *\n\t * Fires events for given {@link module:engine/model/selection~Selection selection} to start selection conversion.\n\t *\n\t * @fires selection\n\t * @fires addMarker\n\t * @fires attribute\n\t * @param {module:engine/model/selection~Selection} selection Selection to convert.\n\t * @param {module:engine/model/markercollection~MarkerCollection} markers Markers connected with converted model.\n\t * @param {module:engine/view/downcastwriter~DowncastWriter} writer View writer that should be used to modify view document.\n\t */\n\tconvertSelection( selection, markers, writer ) {\n\t\tconst markersAtSelection = Array.from( markers.getMarkersAtPosition( selection.getFirstPosition() ) );\n\n\t\tthis.conversionApi.writer = writer;\n\t\tthis.conversionApi.consumable = this._createSelectionConsumable( selection, markersAtSelection );\n\n\t\tthis.fire( 'selection', { selection }, this.conversionApi );\n\n\t\tif ( !selection.isCollapsed ) {\n\t\t\treturn;\n\t\t}\n\n\t\tfor ( const marker of markersAtSelection ) {\n\t\t\tconst markerRange = marker.getRange();\n\n\t\t\tif ( !shouldMarkerChangeBeConverted( selection.getFirstPosition(), marker, this.conversionApi.mapper ) ) {\n\t\t\t\tcontinue;\n\t\t\t}\n\n\t\t\tconst data = {\n\t\t\t\titem: selection,\n\t\t\t\tmarkerName: marker.name,\n\t\t\t\tmarkerRange\n\t\t\t};\n\n\t\t\tif ( this.conversionApi.consumable.test( selection, 'addMarker:' + marker.name ) ) {\n\t\t\t\tthis.fire( 'addMarker:' + marker.name, data, this.conversionApi );\n\t\t\t}\n\t\t}\n\n\t\tfor ( const key of selection.getAttributeKeys() ) {\n\t\t\tconst data = {\n\t\t\t\titem: selection,\n\t\t\t\trange: selection.getFirstRange(),\n\t\t\t\tattributeKey: key,\n\t\t\t\tattributeOldValue: null,\n\t\t\t\tattributeNewValue: selection.getAttribute( key )\n\t\t\t};\n\n\t\t\t// Do not fire event if the attribute has been consumed.\n\t\t\tif ( this.conversionApi.consumable.test( selection, 'attribute:' + data.attributeKey ) ) {\n\t\t\t\tthis.fire( 'attribute:' + data.attributeKey + ':$text', data, this.conversionApi );\n\t\t\t}\n\t\t}\n\n\t\tthis._clearConversionApi();\n\t}\n\n\t/**\n\t * Converts added marker. Fires {@link #event:addMarker addMarker} event for each item\n\t * in marker's range. If range is collapsed single event is dispatched. See event description for more details.\n\t *\n\t * @fires addMarker\n\t * @param {String} markerName Marker name.\n\t * @param {module:engine/model/range~Range} markerRange Marker range.\n\t * @param {module:engine/view/downcastwriter~DowncastWriter} writer View writer that should be used to modify view document.\n\t */\n\tconvertMarkerAdd( markerName, markerRange, writer ) {\n\t\t// Do not convert if range is in graveyard or not in the document (e.g. in DocumentFragment).\n\t\tif ( !markerRange.root.document || markerRange.root.rootName == '$graveyard' ) {\n\t\t\treturn;\n\t\t}\n\n\t\tthis.conversionApi.writer = writer;\n\n\t\t// In markers' case, event name == consumable name.\n\t\tconst eventName = 'addMarker:' + markerName;\n\n\t\t//\n\t\t// First, fire an event for the whole marker.\n\t\t//\n\t\tconst consumable = new Consumable();\n\t\tconsumable.add( markerRange, eventName );\n\n\t\tthis.conversionApi.consumable = consumable;\n\n\t\tthis.fire( eventName, { markerName, markerRange }, this.conversionApi );\n\n\t\t//\n\t\t// Do not fire events for each item inside the range if the range got consumed.\n\t\t//\n\t\tif ( !consumable.test( markerRange, eventName ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\t//\n\t\t// Then, fire an event for each item inside the marker range.\n\t\t//\n\t\tthis.conversionApi.consumable = this._createConsumableForRange( markerRange, eventName );\n\n\t\tfor ( const item of markerRange.getItems() ) {\n\t\t\t// Do not fire event for already consumed items.\n\t\t\tif ( !this.conversionApi.consumable.test( item, eventName ) ) {\n\t\t\t\tcontinue;\n\t\t\t}\n\n\t\t\tconst data = { item, range: Range._createOn( item ), markerName, markerRange };\n\n\t\t\tthis.fire( eventName, data, this.conversionApi );\n\t\t}\n\n\t\tthis._clearConversionApi();\n\t}\n\n\t/**\n\t * Fires conversion of marker removal. Fires {@link #event:removeMarker removeMarker} event with provided data.\n\t *\n\t * @fires removeMarker\n\t * @param {String} markerName Marker name.\n\t * @param {module:engine/model/range~Range} markerRange Marker range.\n\t * @param {module:engine/view/downcastwriter~DowncastWriter} writer View writer that should be used to modify view document.\n\t */\n\tconvertMarkerRemove( markerName, markerRange, writer ) {\n\t\t// Do not convert if range is in graveyard or not in the document (e.g. in DocumentFragment).\n\t\tif ( !markerRange.root.document || markerRange.root.rootName == '$graveyard' ) {\n\t\t\treturn;\n\t\t}\n\n\t\tthis.conversionApi.writer = writer;\n\n\t\tthis.fire( 'removeMarker:' + markerName, { markerName, markerRange }, this.conversionApi );\n\n\t\tthis._clearConversionApi();\n\t}\n\n\t/**\n\t * Creates {@link module:engine/conversion/modelconsumable~ModelConsumable} with values to consume from given range,\n\t * assuming that the range has just been inserted to the model.\n\t *\n\t * @private\n\t * @param {module:engine/model/range~Range} range Inserted range.\n\t * @returns {module:engine/conversion/modelconsumable~ModelConsumable} Values to consume.\n\t */\n\t_createInsertConsumable( range ) {\n\t\tconst consumable = new Consumable();\n\n\t\tfor ( const value of range ) {\n\t\t\tconst item = value.item;\n\n\t\t\tconsumable.add( item, 'insert' );\n\n\t\t\tfor ( const key of item.getAttributeKeys() ) {\n\t\t\t\tconsumable.add( item, 'attribute:' + key );\n\t\t\t}\n\t\t}\n\n\t\treturn consumable;\n\t}\n\n\t/**\n\t * Creates {@link module:engine/conversion/modelconsumable~ModelConsumable} with values to consume for given range.\n\t *\n\t * @private\n\t * @param {module:engine/model/range~Range} range Affected range.\n\t * @param {String} type Consumable type.\n\t * @returns {module:engine/conversion/modelconsumable~ModelConsumable} Values to consume.\n\t */\n\t_createConsumableForRange( range, type ) {\n\t\tconst consumable = new Consumable();\n\n\t\tfor ( const item of range.getItems() ) {\n\t\t\tconsumable.add( item, type );\n\t\t}\n\n\t\treturn consumable;\n\t}\n\n\t/**\n\t * Creates {@link module:engine/conversion/modelconsumable~ModelConsumable} with selection consumable values.\n\t *\n\t * @private\n\t * @param {module:engine/model/selection~Selection} selection Selection to create consumable from.\n\t * @param {Iterable.} markers Markers which contains selection.\n\t * @returns {module:engine/conversion/modelconsumable~ModelConsumable} Values to consume.\n\t */\n\t_createSelectionConsumable( selection, markers ) {\n\t\tconst consumable = new Consumable();\n\n\t\tconsumable.add( selection, 'selection' );\n\n\t\tfor ( const marker of markers ) {\n\t\t\tconsumable.add( selection, 'addMarker:' + marker.name );\n\t\t}\n\n\t\tfor ( const key of selection.getAttributeKeys() ) {\n\t\t\tconsumable.add( selection, 'attribute:' + key );\n\t\t}\n\n\t\treturn consumable;\n\t}\n\n\t/**\n\t * Tests passed `consumable` to check whether given event can be fired and if so, fires it.\n\t *\n\t * @private\n\t * @fires insert\n\t * @fires attribute\n\t * @param {String} type Event type.\n\t * @param {Object} data Event data.\n\t */\n\t_testAndFire( type, data ) {\n\t\tif ( !this.conversionApi.consumable.test( data.item, type ) ) {\n\t\t\t// Do not fire event if the item was consumed.\n\t\t\treturn;\n\t\t}\n\n\t\tconst name = data.item.name || '$text';\n\n\t\tthis.fire( type + ':' + name, data, this.conversionApi );\n\t}\n\n\t/**\n\t * Clears conversion API object.\n\t *\n\t * @private\n\t */\n\t_clearConversionApi() {\n\t\tdelete this.conversionApi.writer;\n\t\tdelete this.conversionApi.consumable;\n\t}\n\n\t/**\n\t * Fired for inserted nodes.\n\t *\n\t * `insert` is a namespace for a class of events. Names of actually called events follow this pattern:\n\t * `insert:name`. `name` is either `'$text'`, when {@link module:engine/model/text~Text a text node} has been inserted,\n\t * or {@link module:engine/model/element~Element#name name} of inserted element.\n\t *\n\t * This way listeners can either listen to a general `insert` event or specific event (for example `insert:paragraph`).\n\t *\n\t * @event insert\n\t * @param {Object} data Additional information about the change.\n\t * @param {module:engine/model/item~Item} data.item Inserted item.\n\t * @param {module:engine/model/range~Range} data.range Range spanning over inserted item.\n\t * @param {module:engine/conversion/downcastdispatcher~DowncastConversionApi} conversionApi Conversion interface\n\t * to be used by callback, passed in `DowncastDispatcher` constructor.\n\t */\n\n\t/**\n\t * Fired for removed nodes.\n\t *\n\t * `remove` is a namespace for a class of events. Names of actually called events follow this pattern:\n\t * `remove:name`. `name` is either `'$text'`, when {@link module:engine/model/text~Text a text node} has been removed,\n\t * or the {@link module:engine/model/element~Element#name name} of removed element.\n\t *\n\t * This way listeners can either listen to a general `remove` event or specific event (for example `remove:paragraph`).\n\t *\n\t * @event remove\n\t * @param {Object} data Additional information about the change.\n\t * @param {module:engine/model/position~Position} data.position Position from which the node has been removed.\n\t * @param {Number} data.length Offset size of the removed node.\n\t * @param {module:engine/conversion/downcastdispatcher~DowncastConversionApi} conversionApi Conversion interface\n\t * to be used by callback, passed in `DowncastDispatcher` constructor.\n\t */\n\n\t/**\n\t * Fired in the following cases:\n\t *\n\t * * when an attribute has been added, changed, or removed from a node,\n\t * * when a node with an attribute is inserted,\n\t * * when collapsed model selection attribute is converted.\n\t *\n\t * `attribute` is a namespace for a class of events. Names of actually called events follow this pattern:\n\t * `attribute:attributeKey:name`. `attributeKey` is the key of added/changed/removed attribute.\n\t * `name` is either `'$text'` if change was on {@link module:engine/model/text~Text a text node},\n\t * or the {@link module:engine/model/element~Element#name name} of element which attribute has changed.\n\t *\n\t * This way listeners can either listen to a general `attribute:bold` event or specific event (for example `attribute:src:image`).\n\t *\n\t * @event attribute\n\t * @param {Object} data Additional information about the change.\n\t * @param {module:engine/model/item~Item|module:engine/model/documentselection~DocumentSelection} data.item Changed item\n\t * or converted selection.\n\t * @param {module:engine/model/range~Range} data.range Range spanning over changed item or selection range.\n\t * @param {String} data.attributeKey Attribute key.\n\t * @param {*} data.attributeOldValue Attribute value before the change. This is `null` when selection attribute is converted.\n\t * @param {*} data.attributeNewValue New attribute value.\n\t * @param {module:engine/conversion/downcastdispatcher~DowncastConversionApi} conversionApi Conversion interface\n\t * to be used by callback, passed in `DowncastDispatcher` constructor.\n\t */\n\n\t/**\n\t * Fired for {@link module:engine/model/selection~Selection selection} changes.\n\t *\n\t * @event selection\n\t * @param {module:engine/model/selection~Selection} selection Selection that is converted.\n\t * @param {module:engine/conversion/downcastdispatcher~DowncastConversionApi} conversionApi Conversion interface\n\t * to be used by callback, passed in `DowncastDispatcher` constructor.\n\t */\n\n\t/**\n\t * Fired when a new marker is added to the model. Also fired when collapsed model selection that is inside marker is converted.\n\t *\n\t * `addMarker` is a namespace for a class of events. Names of actually called events follow this pattern:\n\t * `addMarker:markerName`. By specifying certain marker names, you can make the events even more gradual. For example,\n\t * if markers are named `foo:abc`, `foo:bar`, then it is possible to listen to `addMarker:foo` or `addMarker:foo:abc` and\n\t * `addMarker:foo:bar` events.\n\t *\n\t * If the marker range is not collapsed:\n\t *\n\t * * the event is fired for each item in the marker range one by one,\n\t * * `conversionApi.consumable` includes each item of the marker range and the consumable value is same as event name.\n\t *\n\t * If the marker range is collapsed:\n\t *\n\t * * there is only one event,\n\t * * `conversionApi.consumable` includes marker range with event name.\n\t *\n\t * If selection inside a marker is converted:\n\t *\n\t * * there is only one event,\n\t * * `conversionApi.consumable` includes selection instance with event name.\n\t *\n\t * @event addMarker\n\t * @param {Object} data Additional information about the change.\n\t * @param {module:engine/model/item~Item|module:engine/model/selection~Selection} data.item Item inside the new marker or\n\t * the selection that is being converted.\n\t * @param {module:engine/model/range~Range} [data.range] Range spanning over converted item. Available only in marker conversion, if\n\t * the marker range was not collapsed.\n\t * @param {module:engine/model/range~Range} data.markerRange Marker range.\n\t * @param {String} data.markerName Marker name.\n\t * @param {module:engine/conversion/downcastdispatcher~DowncastConversionApi} conversionApi Conversion interface\n\t * to be used by callback, passed in `DowncastDispatcher` constructor.\n\t */\n\n\t/**\n\t * Fired when marker is removed from the model.\n\t *\n\t * `removeMarker` is a namespace for a class of events. Names of actually called events follow this pattern:\n\t * `removeMarker:markerName`. By specifying certain marker names, you can make the events even more gradual. For example,\n\t * if markers are named `foo:abc`, `foo:bar`, then it is possible to listen to `removeMarker:foo` or `removeMarker:foo:abc` and\n\t * `removeMarker:foo:bar` events.\n\t *\n\t * @event removeMarker\n\t * @param {Object} data Additional information about the change.\n\t * @param {module:engine/model/range~Range} data.markerRange Marker range.\n\t * @param {String} data.markerName Marker name.\n\t * @param {module:engine/conversion/downcastdispatcher~DowncastConversionApi} conversionApi Conversion interface\n\t * to be used by callback, passed in `DowncastDispatcher` constructor.\n\t */\n}\n\nmix( DowncastDispatcher, EmitterMixin );\n\n// Helper function, checks whether change of `marker` at `modelPosition` should be converted. Marker changes are not\n// converted if they happen inside an element with custom conversion method.\n//\n// @param {module:engine/model/position~Position} modelPosition\n// @param {module:engine/model/markercollection~Marker} marker\n// @param {module:engine/conversion/mapper~Mapper} mapper\n// @returns {Boolean}\nfunction shouldMarkerChangeBeConverted( modelPosition, marker, mapper ) {\n\tconst range = marker.getRange();\n\tconst ancestors = Array.from( modelPosition.getAncestors() );\n\tancestors.shift(); // Remove root element. It cannot be passed to `model.Range#containsItem`.\n\tancestors.reverse();\n\n\tconst hasCustomHandling = ancestors.some( element => {\n\t\tif ( range.containsItem( element ) ) {\n\t\t\tconst viewElement = mapper.toViewElement( element );\n\n\t\t\treturn !!viewElement.getCustomProperty( 'addHighlight' );\n\t\t}\n\t} );\n\n\treturn !hasCustomHandling;\n}\n\n/**\n * Conversion interface that is registered for given {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher}\n * and is passed as one of parameters when {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher dispatcher}\n * fires it's events.\n *\n * @interface module:engine/conversion/downcastdispatcher~DowncastConversionApi\n */\n\n/**\n * The {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher} instance.\n *\n * @member {module:engine/conversion/downcastdispatcher~DowncastDispatcher} #dispatcher\n */\n\n/**\n * Stores information about what parts of processed model item are still waiting to be handled. After a piece of model item\n * was converted, appropriate consumable value should be {@link module:engine/conversion/modelconsumable~ModelConsumable#consume consumed}.\n *\n * @member {module:engine/conversion/modelconsumable~ModelConsumable} #consumable\n */\n\n/**\n * The {@link module:engine/conversion/mapper~Mapper} instance.\n *\n * @member {module:engine/conversion/mapper~Mapper} #mapper\n */\n\n/**\n * The {@link module:engine/view/downcastwriter~DowncastWriter} instance used to manipulate data during conversion.\n *\n * @member {module:engine/view/downcastwriter~DowncastWriter} #writer\n */\n","/**\n * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.\n * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license\n */\n\n/**\n * @module engine/model/selection\n */\n\nimport Position from './position';\nimport Element from './element';\nimport Node from './node';\nimport Range from './range';\nimport EmitterMixin from '@ckeditor/ckeditor5-utils/src/emittermixin';\nimport CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';\nimport mix from '@ckeditor/ckeditor5-utils/src/mix';\nimport isIterable from '@ckeditor/ckeditor5-utils/src/isiterable';\n\n/**\n * Selection is a set of {@link module:engine/model/range~Range ranges}. It has a direction specified by its\n * {@link module:engine/model/selection~Selection#anchor anchor} and {@link module:engine/model/selection~Selection#focus focus}\n * (it can be {@link module:engine/model/selection~Selection#isBackward forward or backward}).\n * Additionally, selection may have its own attributes (think – whether text typed in in this selection\n * should have those attributes – e.g. whether you type a bolded text).\n *\n * @mixes module:utils/emittermixin~EmitterMixin\n */\nexport default class Selection {\n\t/**\n\t * Creates a new selection instance based on the given {@link module:engine/model/selection~Selectable selectable}\n\t * or creates an empty selection if no arguments were passed.\n\t *\n\t *\t\t// Creates empty selection without ranges.\n\t *\t\tconst selection = writer.createSelection();\n\t *\n\t *\t\t// Creates selection at the given range.\n\t *\t\tconst range = writer.createRange( start, end );\n\t *\t\tconst selection = writer.createSelection( range );\n\t *\n\t *\t\t// Creates selection at the given ranges\n\t *\t\tconst ranges = [ writer.createRange( start1, end2 ), writer.createRange( star2, end2 ) ];\n\t *\t\tconst selection = writer.createSelection( ranges );\n\t *\n\t *\t\t// Creates selection from the other selection.\n\t *\t\t// Note: It doesn't copies selection attributes.\n\t *\t\tconst otherSelection = writer.createSelection();\n\t *\t\tconst selection = writer.createSelection( otherSelection );\n\t *\n\t *\t\t// Creates selection from the given document selection.\n\t *\t\t// Note: It doesn't copies selection attributes.\n\t *\t\tconst documentSelection = model.document.selection;\n\t *\t\tconst selection = writer.createSelection( documentSelection );\n\t *\n\t *\t\t// Creates selection at the given position.\n\t *\t\tconst position = writer.createPositionFromPath( root, path );\n\t *\t\tconst selection = writer.createSelection( position );\n\t *\n\t *\t\t// Creates selection at the given offset in the given element.\n\t *\t\tconst paragraph = writer.createElement( 'paragraph' );\n\t *\t\tconst selection = writer.createSelection( paragraph, offset );\n\t *\n\t *\t\t// Creates a range inside an {@link module:engine/model/element~Element element} which starts before the\n\t *\t\t// first child of that element and ends after the last child of that element.\n\t *\t\tconst selection = writer.createSelection( paragraph, 'in' );\n\t *\n\t *\t\t// Creates a range on an {@link module:engine/model/item~Item item} which starts before the item and ends\n\t *\t\t// just after the item.\n\t *\t\tconst selection = writer.createSelection( paragraph, 'on' );\n\t *\n\t * Selection's constructor allow passing additional options (`'backward'`) as the last argument.\n\t *\n\t *\t\t// Creates backward selection.\n\t *\t\tconst selection = writer.createSelection( range, { backward: true } );\n\t *\n\t * @param {module:engine/model/selection~Selectable} selectable\n\t * @param {Number|'before'|'end'|'after'|'on'|'in'} [placeOrOffset] Sets place or offset of the selection.\n\t * @param {Object} [options]\n\t * @param {Boolean} [options.backward] Sets this selection instance to be backward.\n\t */\n\tconstructor( selectable, placeOrOffset, options ) {\n\t\t/**\n\t\t * Specifies whether the last added range was added as a backward or forward range.\n\t\t *\n\t\t * @private\n\t\t * @type {Boolean}\n\t\t */\n\t\tthis._lastRangeBackward = false;\n\n\t\t/**\n\t\t * Stores selection ranges.\n\t\t *\n\t\t * @protected\n\t\t * @type {Array.}\n\t\t */\n\t\tthis._ranges = [];\n\n\t\t/**\n\t\t * List of attributes set on current selection.\n\t\t *\n\t\t * @protected\n\t\t * @type {Map.}\n\t\t */\n\t\tthis._attrs = new Map();\n\n\t\tif ( selectable ) {\n\t\t\tthis.setTo( selectable, placeOrOffset, options );\n\t\t}\n\t}\n\n\t/**\n\t * Selection anchor. Anchor is the position from which the selection was started. If a user is making a selection\n\t * by dragging the mouse, the anchor is where the user pressed the mouse button (the beggining of the selection).\n\t *\n\t * Anchor and {@link #focus} define the direction of the selection, which is important\n\t * when expanding/shrinking selection. The focus moves, while the anchor should remain in the same place.\n\t *\n\t * Anchor is always set to the {@link module:engine/model/range~Range#start start} or\n\t * {@link module:engine/model/range~Range#end end} position of the last of selection's ranges. Whether it is\n\t * the `start` or `end` depends on the specified `options.backward`. See the {@link #setTo `setTo()`} method.\n\t *\n\t * May be set to `null` if there are no ranges in the selection.\n\t *\n\t * @see #focus\n\t * @readonly\n\t * @type {module:engine/model/position~Position|null}\n\t */\n\tget anchor() {\n\t\tif ( this._ranges.length > 0 ) {\n\t\t\tconst range = this._ranges[ this._ranges.length - 1 ];\n\n\t\t\treturn this._lastRangeBackward ? range.end : range.start;\n\t\t}\n\n\t\treturn null;\n\t}\n\n\t/**\n\t * Selection focus. Focus is the position where the selection ends. If a user is making a selection\n\t * by dragging the mouse, the focus is where the mouse cursor is.\n\t *\n\t * May be set to `null` if there are no ranges in the selection.\n\t *\n\t * @see #anchor\n\t * @readonly\n\t * @type {module:engine/model/position~Position|null}\n\t */\n\tget focus() {\n\t\tif ( this._ranges.length > 0 ) {\n\t\t\tconst range = this._ranges[ this._ranges.length - 1 ];\n\n\t\t\treturn this._lastRangeBackward ? range.start : range.end;\n\t\t}\n\n\t\treturn null;\n\t}\n\n\t/**\n\t * Whether the selection is collapsed. Selection is collapsed when there is exactly one range in it\n\t * and it is collapsed.\n\t *\n\t * @readonly\n\t * @type {Boolean}\n\t */\n\tget isCollapsed() {\n\t\tconst length = this._ranges.length;\n\n\t\tif ( length === 1 ) {\n\t\t\treturn this._ranges[ 0 ].isCollapsed;\n\t\t} else {\n\t\t\treturn false;\n\t\t}\n\t}\n\n\t/**\n\t * Returns the number of ranges in the selection.\n\t *\n\t * @readonly\n\t * @type {Number}\n\t */\n\tget rangeCount() {\n\t\treturn this._ranges.length;\n\t}\n\n\t/**\n\t * Specifies whether the selection's {@link #focus} precedes the selection's {@link #anchor}.\n\t *\n\t * @readonly\n\t * @type {Boolean}\n\t */\n\tget isBackward() {\n\t\treturn !this.isCollapsed && this._lastRangeBackward;\n\t}\n\n\t/**\n\t * Checks whether this selection is equal to the given selection. Selections are equal if they have the same directions,\n\t * the same number of ranges and all ranges from one selection equal to ranges from the another selection.\n\t *\n\t * @param {module:engine/model/selection~Selection|module:engine/model/documentselection~DocumentSelection} otherSelection\n\t * Selection to compare with.\n\t * @returns {Boolean} `true` if selections are equal, `false` otherwise.\n\t */\n\tisEqual( otherSelection ) {\n\t\tif ( this.rangeCount != otherSelection.rangeCount ) {\n\t\t\treturn false;\n\t\t} else if ( this.rangeCount === 0 ) {\n\t\t\treturn true;\n\t\t}\n\n\t\tif ( !this.anchor.isEqual( otherSelection.anchor ) || !this.focus.isEqual( otherSelection.focus ) ) {\n\t\t\treturn false;\n\t\t}\n\n\t\tfor ( const thisRange of this._ranges ) {\n\t\t\tlet found = false;\n\n\t\t\tfor ( const otherRange of otherSelection._ranges ) {\n\t\t\t\tif ( thisRange.isEqual( otherRange ) ) {\n\t\t\t\t\tfound = true;\n\t\t\t\t\tbreak;\n\t\t\t\t}\n\t\t\t}\n\n\t\t\tif ( !found ) {\n\t\t\t\treturn false;\n\t\t\t}\n\t\t}\n\n\t\treturn true;\n\t}\n\n\t/**\n\t * Returns an iterable object that iterates over copies of selection ranges.\n\t *\n\t * @returns {Iterable.}\n\t */\n\t* getRanges() {\n\t\tfor ( const range of this._ranges ) {\n\t\t\tyield new Range( range.start, range.end );\n\t\t}\n\t}\n\n\t/**\n\t * Returns a copy of the first range in the selection.\n\t * First range is the one which {@link module:engine/model/range~Range#start start} position\n\t * {@link module:engine/model/position~Position#isBefore is before} start position of all other ranges\n\t * (not to confuse with the first range added to the selection).\n\t *\n\t * Returns `null` if there are no ranges in selection.\n\t *\n\t * @returns {module:engine/model/range~Range|null}\n\t */\n\tgetFirstRange() {\n\t\tlet first = null;\n\n\t\tfor ( const range of this._ranges ) {\n\t\t\tif ( !first || range.start.isBefore( first.start ) ) {\n\t\t\t\tfirst = range;\n\t\t\t}\n\t\t}\n\n\t\treturn first ? new Range( first.start, first.end ) : null;\n\t}\n\n\t/**\n\t * Returns a copy of the last range in the selection.\n\t * Last range is the one which {@link module:engine/model/range~Range#end end} position\n\t * {@link module:engine/model/position~Position#isAfter is after} end position of all other ranges (not to confuse with the range most\n\t * recently added to the selection).\n\t *\n\t * Returns `null` if there are no ranges in selection.\n\t *\n\t * @returns {module:engine/model/range~Range|null}\n\t */\n\tgetLastRange() {\n\t\tlet last = null;\n\n\t\tfor ( const range of this._ranges ) {\n\t\t\tif ( !last || range.end.isAfter( last.end ) ) {\n\t\t\t\tlast = range;\n\t\t\t}\n\t\t}\n\n\t\treturn last ? new Range( last.start, last.end ) : null;\n\t}\n\n\t/**\n\t * Returns the first position in the selection.\n\t * First position is the position that {@link module:engine/model/position~Position#isBefore is before}\n\t * any other position in the selection.\n\t *\n\t * Returns `null` if there are no ranges in selection.\n\t *\n\t * @returns {module:engine/model/position~Position|null}\n\t */\n\tgetFirstPosition() {\n\t\tconst first = this.getFirstRange();\n\n\t\treturn first ? first.start.clone() : null;\n\t}\n\n\t/**\n\t * Returns the last position in the selection.\n\t * Last position is the position that {@link module:engine/model/position~Position#isAfter is after}\n\t * any other position in the selection.\n\t *\n\t * Returns `null` if there are no ranges in selection.\n\t *\n\t * @returns {module:engine/model/position~Position|null}\n\t */\n\tgetLastPosition() {\n\t\tconst lastRange = this.getLastRange();\n\n\t\treturn lastRange ? lastRange.end.clone() : null;\n\t}\n\n\t/**\n\t * Sets this selection's ranges and direction to the specified location based on the given\n\t * {@link module:engine/model/selection~Selectable selectable}.\n\t *\n\t *\t\t// Removes all selection's ranges.\n\t *\t\tselection.setTo( null );\n\t *\n\t *\t\t// Sets selection to the given range.\n\t *\t\tconst range = writer.createRange( start, end );\n\t *\t\tselection.setTo( range );\n\t *\n\t *\t\t// Sets selection to given ranges.\n\t *\t\tconst ranges = [ writer.createRange( start1, end2 ), writer.createRange( star2, end2 ) ];\n\t *\t\tselection.setTo( ranges );\n\t *\n\t *\t\t// Sets selection to other selection.\n\t *\t\t// Note: It doesn't copies selection attributes.\n\t *\t\tconst otherSelection = writer.createSelection();\n\t *\t\tselection.setTo( otherSelection );\n\t *\n\t *\t\t// Sets selection to the given document selection.\n\t *\t\t// Note: It doesn't copies selection attributes.\n\t *\t\tconst documentSelection = new DocumentSelection( doc );\n\t *\t\tselection.setTo( documentSelection );\n\t *\n\t *\t\t// Sets collapsed selection at the given position.\n\t *\t\tconst position = writer.createPositionFromPath( root, path );\n\t *\t\tselection.setTo( position );\n\t *\n\t *\t\t// Sets collapsed selection at the position of the given node and an offset.\n\t *\t\tselection.setTo( paragraph, offset );\n\t *\n\t * Creates a range inside an {@link module:engine/model/element~Element element} which starts before the first child of\n \t * that element and ends after the last child of that element.\n\t *\n\t *\t\tselection.setTo( paragraph, 'in' );\n\t *\n\t * Creates a range on an {@link module:engine/model/item~Item item} which starts before the item and ends just after the item.\n\t *\n\t *\t\tselection.setTo( paragraph, 'on' );\n\t *\n\t * `Selection#setTo()`' method allow passing additional options (`backward`) as the last argument.\n\t *\n\t *\t\t// Sets backward selection.\n\t *\t\tconst selection = writer.createSelection( range, { backward: true } );\n\t *\n\t * @param {module:engine/model/selection~Selectable} selectable\n\t * @param {Number|'before'|'end'|'after'|'on'|'in'} [placeOrOffset] Sets place or offset of the selection.\n\t * @param {Object} [options]\n\t * @param {Boolean} [options.backward] Sets this selection instance to be backward.\n\t */\n\tsetTo( selectable, placeOrOffset, options ) {\n\t\tif ( selectable === null ) {\n\t\t\tthis._setRanges( [] );\n\t\t} else if ( selectable instanceof Selection ) {\n\t\t\tthis._setRanges( selectable.getRanges(), selectable.isBackward );\n\t\t} else if ( selectable && typeof selectable.getRanges == 'function' ) {\n\t\t\t// We assume that the selectable is a DocumentSelection.\n\t\t\t// It can't be imported here, because it would lead to circular imports.\n\t\t\tthis._setRanges( selectable.getRanges(), selectable.isBackward );\n\t\t} else if ( selectable instanceof Range ) {\n\t\t\tthis._setRanges( [ selectable ], !!placeOrOffset && !!placeOrOffset.backward );\n\t\t} else if ( selectable instanceof Position ) {\n\t\t\tthis._setRanges( [ new Range( selectable ) ] );\n\t\t} else if ( selectable instanceof Node ) {\n\t\t\tconst backward = !!options && !!options.backward;\n\t\t\tlet range;\n\n\t\t\tif ( placeOrOffset == 'in' ) {\n\t\t\t\trange = Range._createIn( selectable );\n\t\t\t} else if ( placeOrOffset == 'on' ) {\n\t\t\t\trange = Range._createOn( selectable );\n\t\t\t} else if ( placeOrOffset !== undefined ) {\n\t\t\t\trange = new Range( Position._createAt( selectable, placeOrOffset ) );\n\t\t\t} else {\n\t\t\t\t/**\n\t\t\t\t * selection.setTo requires the second parameter when the first parameter is a node.\n\t\t\t\t *\n\t\t\t\t * @error model-selection-setTo-required-second-parameter\n\t\t\t\t */\n\t\t\t\tthrow new CKEditorError(\n\t\t\t\t\t'model-selection-setTo-required-second-parameter: ' +\n\t\t\t\t\t'selection.setTo requires the second parameter when the first parameter is a node.',\n\t\t\t\t\t[ this, selectable ]\n\t\t\t\t);\n\t\t\t}\n\n\t\t\tthis._setRanges( [ range ], backward );\n\t\t} else if ( isIterable( selectable ) ) {\n\t\t\t// We assume that the selectable is an iterable of ranges.\n\t\t\tthis._setRanges( selectable, placeOrOffset && !!placeOrOffset.backward );\n\t\t} else {\n\t\t\t/**\n\t\t\t * Cannot set the selection to the given place.\n\t\t\t *\n\t\t\t * Invalid parameters were specified when setting the selection. Common issues:\n\t\t\t *\n\t\t\t * * A {@link module:engine/model/textproxy~TextProxy} instance was passed instead of\n\t\t\t * a real {@link module:engine/model/text~Text}.\n\t\t\t * * View nodes were passed instead of model nodes.\n\t\t\t * * `null`/`undefined` was passed.\n\t\t\t *\n\t\t\t * @error model-selection-setTo-not-selectable\n\t\t\t */\n\t\t\tthrow new CKEditorError(\n\t\t\t\t'model-selection-setTo-not-selectable: Cannot set the selection to the given place.',\n\t\t\t\t[ this, selectable ]\n\t\t\t);\n\t\t}\n\t}\n\n\t/**\n\t * Replaces all ranges that were added to the selection with given array of ranges. Last range of the array\n\t * is treated like the last added range and is used to set {@link module:engine/model/selection~Selection#anchor} and\n\t * {@link module:engine/model/selection~Selection#focus}. Accepts a flag describing in which direction the selection is made.\n\t *\n\t * @protected\n\t * @fires change:range\n\t * @param {Iterable.} newRanges Ranges to set.\n\t * @param {Boolean} [isLastBackward=false] Flag describing if last added range was selected forward - from start to end (`false`)\n\t * or backward - from end to start (`true`).\n\t */\n\t_setRanges( newRanges, isLastBackward = false ) {\n\t\tnewRanges = Array.from( newRanges );\n\n\t\t// Check whether there is any range in new ranges set that is different than all already added ranges.\n\t\tconst anyNewRange = newRanges.some( newRange => {\n\t\t\tif ( !( newRange instanceof Range ) ) {\n\t\t\t\t/**\n\t\t\t\t * Selection range set to an object that is not an instance of {@link module:engine/model/range~Range}.\n\t\t\t\t *\n\t\t\t\t * Only {@link module:engine/model/range~Range} instances can be used to set a selection.\n\t\t\t\t * Common mistakes leading to this error are:\n\t\t\t\t *\n\t\t\t\t * * using DOM `Range` object,\n\t\t\t\t * * incorrect CKEditor 5 installation with multiple `ckeditor5-engine` packages having different versions.\n\t\t\t\t *\n\t\t\t\t * @error model-selection-set-ranges-not-range\n\t\t\t\t */\n\t\t\t\tthrow new CKEditorError(\n\t\t\t\t\t'model-selection-set-ranges-not-range: ' +\n\t\t\t\t\t'Selection range set to an object that is not an instance of model.Range.',\n\t\t\t\t\t[ this, newRanges ]\n\t\t\t\t);\n\t\t\t}\n\n\t\t\treturn this._ranges.every( oldRange => {\n\t\t\t\treturn !oldRange.isEqual( newRange );\n\t\t\t} );\n\t\t} );\n\n\t\t// Don't do anything if nothing changed.\n\t\tif ( newRanges.length === this._ranges.length && !anyNewRange ) {\n\t\t\treturn;\n\t\t}\n\n\t\tthis._removeAllRanges();\n\n\t\tfor ( const range of newRanges ) {\n\t\t\tthis._pushRange( range );\n\t\t}\n\n\t\tthis._lastRangeBackward = !!isLastBackward;\n\n\t\tthis.fire( 'change:range', { directChange: true } );\n\t}\n\n\t/**\n\t * Moves {@link module:engine/model/selection~Selection#focus} to the specified location.\n\t *\n\t * The location can be specified in the same form as\n\t * {@link module:engine/model/writer~Writer#createPositionAt writer.createPositionAt()} parameters.\n\t *\n\t * @fires change:range\n\t * @param {module:engine/model/item~Item|module:engine/model/position~Position} itemOrPosition\n\t * @param {Number|'end'|'before'|'after'} [offset] Offset or one of the flags. Used only when\n\t * first parameter is a {@link module:engine/model/item~Item model item}.\n\t */\n\tsetFocus( itemOrPosition, offset ) {\n\t\tif ( this.anchor === null ) {\n\t\t\t/**\n\t\t\t * Cannot set selection focus if there are no ranges in selection.\n\t\t\t *\n\t\t\t * @error model-selection-setFocus-no-ranges\n\t\t\t */\n\t\t\tthrow new CKEditorError(\n\t\t\t\t'model-selection-setFocus-no-ranges: Cannot set selection focus if there are no ranges in selection.',\n\t\t\t\t[ this, itemOrPosition ]\n\t\t\t);\n\t\t}\n\n\t\tconst newFocus = Position._createAt( itemOrPosition, offset );\n\n\t\tif ( newFocus.compareWith( this.focus ) == 'same' ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst anchor = this.anchor;\n\n\t\tif ( this._ranges.length ) {\n\t\t\tthis._popRange();\n\t\t}\n\n\t\tif ( newFocus.compareWith( anchor ) == 'before' ) {\n\t\t\tthis._pushRange( new Range( newFocus, anchor ) );\n\t\t\tthis._lastRangeBackward = true;\n\t\t} else {\n\t\t\tthis._pushRange( new Range( anchor, newFocus ) );\n\t\t\tthis._lastRangeBackward = false;\n\t\t}\n\n\t\tthis.fire( 'change:range', { directChange: true } );\n\t}\n\n\t/**\n\t * Gets an attribute value for given key or `undefined` if that attribute is not set on the selection.\n\t *\n\t * @param {String} key Key of attribute to look for.\n\t * @returns {*} Attribute value or `undefined`.\n\t */\n\tgetAttribute( key ) {\n\t\treturn this._attrs.get( key );\n\t}\n\n\t/**\n\t * Returns iterable that iterates over this selection's attributes.\n\t *\n\t * Attributes are returned as arrays containing two items. First one is attribute key and second is attribute value.\n\t * This format is accepted by native `Map` object and also can be passed in `Node` constructor.\n\t *\n\t * @returns {Iterable.<*>}\n\t */\n\tgetAttributes() {\n\t\treturn this._attrs.entries();\n\t}\n\n\t/**\n\t * Returns iterable that iterates over this selection's attribute keys.\n\t *\n\t * @returns {Iterable.}\n\t */\n\tgetAttributeKeys() {\n\t\treturn this._attrs.keys();\n\t}\n\n\t/**\n\t * Checks if the selection has an attribute for given key.\n\t *\n\t * @param {String} key Key of attribute to check.\n\t * @returns {Boolean} `true` if attribute with given key is set on selection, `false` otherwise.\n\t */\n\thasAttribute( key ) {\n\t\treturn this._attrs.has( key );\n\t}\n\n\t/**\n\t * Removes an attribute with given key from the selection.\n\t *\n\t * If given attribute was set on the selection, fires the {@link #event:change:range} event with\n\t * removed attribute key.\n\t *\n\t * @fires change:attribute\n\t * @param {String} key Key of attribute to remove.\n\t */\n\tremoveAttribute( key ) {\n\t\tif ( this.hasAttribute( key ) ) {\n\t\t\tthis._attrs.delete( key );\n\n\t\t\tthis.fire( 'change:attribute', { attributeKeys: [ key ], directChange: true } );\n\t\t}\n\t}\n\n\t/**\n\t * Sets attribute on the selection. If attribute with the same key already is set, it's value is overwritten.\n\t *\n\t * If the attribute value has changed, fires the {@link #event:change:range} event with\n\t * the attribute key.\n\t *\n\t * @fires change:attribute\n\t * @param {String} key Key of attribute to set.\n\t * @param {*} value Attribute value.\n\t */\n\tsetAttribute( key, value ) {\n\t\tif ( this.getAttribute( key ) !== value ) {\n\t\t\tthis._attrs.set( key, value );\n\n\t\t\tthis.fire( 'change:attribute', { attributeKeys: [ key ], directChange: true } );\n\t\t}\n\t}\n\n\t/**\n\t * Returns the selected element. {@link module:engine/model/element~Element Element} is considered as selected if there is only\n\t * one range in the selection, and that range contains exactly one element.\n\t * Returns `null` if there is no selected element.\n\t *\n\t * @returns {module:engine/model/element~Element|null}\n\t */\n\tgetSelectedElement() {\n\t\tif ( this.rangeCount !== 1 ) {\n\t\t\treturn null;\n\t\t}\n\n\t\tconst range = this.getFirstRange();\n\t\tconst nodeAfterStart = range.start.nodeAfter;\n\t\tconst nodeBeforeEnd = range.end.nodeBefore;\n\n\t\treturn ( nodeAfterStart instanceof Element && nodeAfterStart == nodeBeforeEnd ) ? nodeAfterStart : null;\n\t}\n\n\t/**\n\t * Checks whether this object is of the given.\n\t *\n\t *\t\tselection.is( 'selection' ); // -> true\n\t *\t\tselection.is( 'model:selection' ); // -> true\n\t *\n\t *\t\tselection.is( 'view:selection' ); // -> false\n\t *\t\tselection.is( 'range' ); // -> false\n\t *\n\t * {@link module:engine/model/node~Node#is Check the entire list of model objects} which implement the `is()` method.\n\t *\n\t * @param {String} type\n\t * @returns {Boolean}\n\t */\n\tis( type ) {\n\t\treturn type == 'selection' || type == 'model:selection';\n\t}\n\n\t/**\n\t * Gets elements of type {@link module:engine/model/schema~Schema#isBlock \"block\"} touched by the selection.\n\t *\n\t * This method's result can be used for example to apply block styling to all blocks covered by this selection.\n\t *\n\t * **Note:** `getSelectedBlocks()` returns blocks that are nested in other non-block elements\n\t * but will not return blocks nested in other blocks.\n\t *\n\t * In this case the function will return exactly all 3 paragraphs (note: `` is not a block itself):\n\t *\n\t *\t\t[a\n\t *\t\t\n\t *\t\t\tb\n\t *\t\t
\n\t *\t\tc]d\n\t *\n\t * In this case the paragraph will also be returned, despite the collapsed selection:\n\t *\n\t *\t\t[]a\n\t *\n\t * In such a scenario, however, only blocks A, B & E will be returned as blocks C & D are nested in block B:\n\t *\n\t *\t\t[\n\t *\t\t\n\t *\t\t\t\n\t *\t\t\t\n\t *\t\t\n\t *\t\t]\n\t *\n\t * If the selection is inside a block all the inner blocks (A & B) are returned:\n\t *\n\t * \t\t\n\t *\t\t\t[a\n\t * \t\t\tb]\n\t * \t\t\n\t *\n\t * **Special case**: If a selection ends at the beginning of a block, that block is not returned as from user perspective\n\t * this block wasn't selected. See [#984](https://github.com/ckeditor/ckeditor5-engine/issues/984) for more details.\n\t *\n\t *\t\t[a\n\t *\t\tb\n\t *\t\t]c // this block will not be returned\n\t *\n\t * @returns {Iterable.}\n\t */\n\t* getSelectedBlocks() {\n\t\tconst visited = new WeakSet();\n\n\t\tfor ( const range of this.getRanges() ) {\n\t\t\t// Get start block of range in case of a collapsed range.\n\t\t\tconst startBlock = getParentBlock( range.start, visited );\n\n\t\t\tif ( startBlock && isTopBlockInRange( startBlock, range ) ) {\n\t\t\t\tyield startBlock;\n\t\t\t}\n\n\t\t\tfor ( const value of range.getWalker() ) {\n\t\t\t\tconst block = value.item;\n\n\t\t\t\tif ( value.type == 'elementEnd' && isUnvisitedTopBlock( block, visited, range ) ) {\n\t\t\t\t\tyield block;\n\t\t\t\t}\n\t\t\t}\n\n\t\t\tconst endBlock = getParentBlock( range.end, visited );\n\n\t\t\t// #984. Don't return the end block if the range ends right at its beginning.\n\t\t\tif ( endBlock && !range.end.isTouching( Position._createAt( endBlock, 0 ) ) && isTopBlockInRange( endBlock, range ) ) {\n\t\t\t\tyield endBlock;\n\t\t\t}\n\t\t}\n\t}\n\n\t/**\n\t * Checks whether the selection contains the entire content of the given element. This means that selection must start\n\t * at a position {@link module:engine/model/position~Position#isTouching touching} the element's start and ends at position\n\t * touching the element's end.\n\t *\n\t * By default, this method will check whether the entire content of the selection's current root is selected.\n\t * Useful to check if e.g. the user has just pressed Ctrl + A.\n\t *\n\t * @param {module:engine/model/element~Element} [element=this.anchor.root]\n\t * @returns {Boolean}\n\t */\n\tcontainsEntireContent( element = this.anchor.root ) {\n\t\tconst limitStartPosition = Position._createAt( element, 0 );\n\t\tconst limitEndPosition = Position._createAt( element, 'end' );\n\n\t\treturn limitStartPosition.isTouching( this.getFirstPosition() ) &&\n\t\t\tlimitEndPosition.isTouching( this.getLastPosition() );\n\t}\n\n\t/**\n\t * Adds given range to internal {@link #_ranges ranges array}. Throws an error\n\t * if given range is intersecting with any range that is already stored in this selection.\n\t *\n\t * @protected\n\t * @param {module:engine/model/range~Range} range Range to add.\n\t */\n\t_pushRange( range ) {\n\t\tthis._checkRange( range );\n\t\tthis._ranges.push( new Range( range.start, range.end ) );\n\t}\n\n\t/**\n\t * Checks if given range intersects with ranges that are already in the selection. Throws an error if it does.\n\t *\n\t * @protected\n\t * @param {module:engine/model/range~Range} range Range to check.\n\t */\n\t_checkRange( range ) {\n\t\tfor ( let i = 0; i < this._ranges.length; i++ ) {\n\t\t\tif ( range.isIntersecting( this._ranges[ i ] ) ) {\n\t\t\t\t/**\n\t\t\t\t * Trying to add a range that intersects with another range in the selection.\n\t\t\t\t *\n\t\t\t\t * @error model-selection-range-intersects\n\t\t\t\t * @param {module:engine/model/range~Range} addedRange Range that was added to the selection.\n\t\t\t\t * @param {module:engine/model/range~Range} intersectingRange Range in the selection that intersects with `addedRange`.\n\t\t\t\t */\n\t\t\t\tthrow new CKEditorError(\n\t\t\t\t\t'model-selection-range-intersects: Trying to add a range that intersects with another range in the selection.',\n\t\t\t\t\t[ this, range ],\n\t\t\t\t\t{ addedRange: range, intersectingRange: this._ranges[ i ] }\n\t\t\t\t);\n\t\t\t}\n\t\t}\n\t}\n\n\t/**\n\t * Deletes ranges from internal range array. Uses {@link #_popRange _popRange} to\n\t * ensure proper ranges removal.\n\t *\n\t * @protected\n\t */\n\t_removeAllRanges() {\n\t\twhile ( this._ranges.length > 0 ) {\n\t\t\tthis._popRange();\n\t\t}\n\t}\n\n\t/**\n\t * Removes most recently added range from the selection.\n\t *\n\t * @protected\n\t */\n\t_popRange() {\n\t\tthis._ranges.pop();\n\t}\n\n\t/**\n\t * Fired when selection range(s) changed.\n\t *\n\t * @event change:range\n\t * @param {Boolean} directChange In case of {@link module:engine/model/selection~Selection} class it is always set\n\t * to `true` which indicates that the selection change was caused by a direct use of selection's API.\n\t * The {@link module:engine/model/documentselection~DocumentSelection}, however, may change because its position\n\t * was directly changed through the {@link module:engine/model/writer~Writer writer} or because its position was\n\t * changed because the structure of the model has been changed (which means an indirect change).\n\t * The indirect change does not occur in case of normal (detached) selections because they are \"static\" (as \"not live\")\n\t * which mean that they are not updated once the document changes.\n\t */\n\n\t/**\n\t * Fired when selection attribute changed.\n\t *\n\t * @event change:attribute\n\t * @param {Boolean} directChange In case of {@link module:engine/model/selection~Selection} class it is always set\n\t * to `true` which indicates that the selection change was caused by a direct use of selection's API.\n\t * The {@link module:engine/model/documentselection~DocumentSelection}, however, may change because its attributes\n\t * were directly changed through the {@link module:engine/model/writer~Writer writer} or because its position was\n\t * changed in the model and its attributes were refreshed (which means an indirect change).\n\t * The indirect change does not occur in case of normal (detached) selections because they are \"static\" (as \"not live\")\n\t * which mean that they are not updated once the document changes.\n\t * @param {Array.} attributeKeys Array containing keys of attributes that changed.\n\t */\n}\n\nmix( Selection, EmitterMixin );\n\n// Checks whether the given element extends $block in the schema and has a parent (is not a root).\n// Marks it as already visited.\nfunction isUnvisitedBlock( element, visited ) {\n\tif ( visited.has( element ) ) {\n\t\treturn false;\n\t}\n\n\tvisited.add( element );\n\n\treturn element.document.model.schema.isBlock( element ) && element.parent;\n}\n\n// Checks if the given element is a $block was not previously visited and is a top block in a range.\nfunction isUnvisitedTopBlock( element, visited, range ) {\n\treturn isUnvisitedBlock( element, visited ) && isTopBlockInRange( element, range );\n}\n\n// Finds the lowest element in position's ancestors which is a block.\n// It will search until first ancestor that is a limit element.\n// Marks all ancestors as already visited to not include any of them later on.\nfunction getParentBlock( position, visited ) {\n\tconst schema = position.parent.document.model.schema;\n\n\tconst ancestors = position.parent.getAncestors( { parentFirst: true, includeSelf: true } );\n\n\tlet hasParentLimit = false;\n\n\tconst block = ancestors.find( element => {\n\t\t// Stop searching after first parent node that is limit element.\n\t\tif ( hasParentLimit ) {\n\t\t\treturn false;\n\t\t}\n\n\t\thasParentLimit = schema.isLimit( element );\n\n\t\treturn !hasParentLimit && isUnvisitedBlock( element, visited );\n\t} );\n\n\t// Mark all ancestors of this position's parent, because find() might've stopped early and\n\t// the found block may be a child of another block.\n\tancestors.forEach( element => visited.add( element ) );\n\n\treturn block;\n}\n\n// Checks if the blocks is not nested in other block inside a range.\n//\n// @param {module:engine/model/elmenent~Element} block Block to check.\n// @param {module:engine/model/range~Range} range Range to check.\nfunction isTopBlockInRange( block, range ) {\n\tconst parentBlock = findAncestorBlock( block );\n\n\tif ( !parentBlock ) {\n\t\treturn true;\n\t}\n\n\t// Add loose flag to check as parentRange can be equal to range.\n\tconst isParentInRange = range.containsRange( Range._createOn( parentBlock ), true );\n\n\treturn !isParentInRange;\n}\n\n// Returns first ancestor block of a node.\n//\n// @param {module:engine/model/node~Node} node\n// @returns {module:engine/model/node~Node|undefined}\nfunction findAncestorBlock( node ) {\n\tconst schema = node.document.model.schema;\n\n\tlet parent = node.parent;\n\n\twhile ( parent ) {\n\t\tif ( schema.isBlock( parent ) ) {\n\t\t\treturn parent;\n\t\t}\n\n\t\tparent = parent.parent;\n\t}\n}\n\n/**\n * An entity that is used to set selection.\n *\n * See also {@link module:engine/model/selection~Selection#setTo}\n *\n * @typedef {\n * module:engine/model/selection~Selection|\n * module:engine/model/documentselection~DocumentSelection|\n * module:engine/model/position~Position|\n * module:engine/model/range~Range|\n * module:engine/model/node~Node|\n * Iterable.|\n * null\n * } module:engine/model/selection~Selectable\n */\n","/**\n * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.\n * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license\n */\n\n/**\n * @module engine/model/liverange\n */\n\nimport Range from './range';\nimport EmitterMixin from '@ckeditor/ckeditor5-utils/src/emittermixin';\nimport mix from '@ckeditor/ckeditor5-utils/src/mix';\n\n/**\n * `LiveRange` is a type of {@link module:engine/model/range~Range Range}\n * that updates itself as {@link module:engine/model/document~Document document}\n * is changed through operations. It may be used as a bookmark.\n *\n * **Note:** Be very careful when dealing with `LiveRange`. Each `LiveRange` instance bind events that might\n * have to be unbound. Use {@link module:engine/model/liverange~LiveRange#detach detach} whenever you don't need `LiveRange` anymore.\n */\nexport default class LiveRange extends Range {\n\t/**\n\t * Creates a live range.\n\t *\n\t * @see module:engine/model/range~Range\n\t */\n\tconstructor( start, end ) {\n\t\tsuper( start, end );\n\n\t\tbindWithDocument.call( this );\n\t}\n\n\t/**\n\t * Unbinds all events previously bound by `LiveRange`. Use it whenever you don't need `LiveRange` instance\n\t * anymore (i.e. when leaving scope in which it was declared or before re-assigning variable that was\n\t * referring to it).\n\t */\n\tdetach() {\n\t\tthis.stopListening();\n\t}\n\n\t/**\n\t * Checks whether this object is of the given.\n\t *\n\t *\t\tliveRange.is( 'range' ); // -> true\n\t *\t\tliveRange.is( 'model:range' ); // -> true\n\t *\t\tliveRange.is( 'liveRange' ); // -> true\n\t *\t\tliveRange.is( 'model:liveRange' ); // -> true\n\t *\n\t *\t\tliveRange.is( 'view:range' ); // -> false\n\t *\t\tliveRange.is( 'documentSelection' ); // -> false\n\t *\n\t * {@link module:engine/model/node~Node#is Check the entire list of model objects} which implement the `is()` method.\n\t *\n\t * @param {String} type\n\t * @returns {Boolean}\n\t */\n\tis( type ) {\n\t\treturn type == 'liveRange' || type == 'model:liveRange' || super.is( type );\n\t}\n\n\t/**\n\t * Creates a {@link module:engine/model/range~Range range instance} that is equal to this live range.\n\t *\n\t * @returns {module:engine/model/range~Range}\n\t */\n\ttoRange() {\n\t\treturn new Range( this.start, this.end );\n\t}\n\n\t/**\n\t * Creates a `LiveRange` instance that is equal to the given range.\n\t *\n\t * @param {module:engine/model/range~Range} range\n\t * @returns {module:engine/model/liverange~LiveRange}\n\t */\n\tstatic fromRange( range ) {\n\t\treturn new LiveRange( range.start, range.end );\n\t}\n\n\t/**\n\t * @see module:engine/model/range~Range._createIn\n\t * @static\n\t * @protected\n\t * @method module:engine/model/liverange~LiveRange._createIn\n\t * @param {module:engine/model/element~Element} element\n\t * @returns {module:engine/model/liverange~LiveRange}\n\t */\n\n\t/**\n\t * @see module:engine/model/range~Range._createOn\n\t * @static\n\t * @protected\n\t * @method module:engine/model/liverange~LiveRange._createOn\n\t * @param {module:engine/model/element~Element} element\n\t * @returns {module:engine/model/liverange~LiveRange}\n\t */\n\n\t/**\n\t * @see module:engine/model/range~Range._createFromPositionAndShift\n\t * @static\n\t * @protected\n\t * @method module:engine/model/liverange~LiveRange._createFromPositionAndShift\n\t * @param {module:engine/model/position~Position} position\n\t * @param {Number} shift\n\t * @returns {module:engine/model/liverange~LiveRange}\n\t */\n\n\t/**\n\t * Fired when `LiveRange` instance boundaries have changed due to changes in the\n\t * {@link module:engine/model/document~Document document}.\n\t *\n\t * @event change:range\n\t * @param {module:engine/model/range~Range} oldRange Range with start and end position equal to start and end position of this live\n\t * range before it got changed.\n\t * @param {Object} data Object with additional information about the change.\n\t * @param {module:engine/model/position~Position|null} data.deletionPosition Source position for remove and merge changes.\n\t * Available if the range was moved to the graveyard root, `null` otherwise.\n\t */\n\n\t/**\n\t * Fired when `LiveRange` instance boundaries have not changed after a change in {@link module:engine/model/document~Document document}\n\t * but the change took place inside the range, effectively changing its content.\n\t *\n\t * @event change:content\n\t * @param {module:engine/model/range~Range} range Range with start and end position equal to start and end position of\n\t * change range.\n\t * @param {Object} data Object with additional information about the change.\n\t * @param {null} data.deletionPosition Due to the nature of this event, this property is always set to `null`. It is passed\n\t * for compatibility with the {@link module:engine/model/liverange~LiveRange#event:change:range} event.\n\t */\n}\n\n// Binds this `LiveRange` to the {@link module:engine/model/document~Document document}\n// that owns this range's {@link module:engine/model/range~Range#root root}.\n//\n// @private\nfunction bindWithDocument() {\n\tthis.listenTo(\n\t\tthis.root.document.model,\n\t\t'applyOperation',\n\t\t( event, args ) => {\n\t\t\tconst operation = args[ 0 ];\n\n\t\t\tif ( !operation.isDocumentOperation ) {\n\t\t\t\treturn;\n\t\t\t}\n\n\t\t\ttransform.call( this, operation );\n\t\t},\n\t\t{ priority: 'low' }\n\t);\n}\n\n// Updates this range accordingly to the updates applied to the model. Bases on change events.\n//\n// @private\n// @param {module:engine/model/operation/operation~Operation} operation Executed operation.\nfunction transform( operation ) {\n\t// Transform the range by the operation. Join the result ranges if needed.\n\tconst ranges = this.getTransformedByOperation( operation );\n\tconst result = Range._createFromRanges( ranges );\n\n\tconst boundariesChanged = !result.isEqual( this );\n\tconst contentChanged = doesOperationChangeRangeContent( this, operation );\n\n\tlet deletionPosition = null;\n\n\tif ( boundariesChanged ) {\n\t\t// If range boundaries have changed, fire `change:range` event.\n\t\t//\n\t\tif ( result.root.rootName == '$graveyard' ) {\n\t\t\t// If the range was moved to the graveyard root, set `deletionPosition`.\n\t\t\tif ( operation.type == 'remove' ) {\n\t\t\t\tdeletionPosition = operation.sourcePosition;\n\t\t\t} else {\n\t\t\t\t// Merge operation.\n\t\t\t\tdeletionPosition = operation.deletionPosition;\n\t\t\t}\n\t\t}\n\n\t\tconst oldRange = this.toRange();\n\n\t\tthis.start = result.start;\n\t\tthis.end = result.end;\n\n\t\tthis.fire( 'change:range', oldRange, { deletionPosition } );\n\t} else if ( contentChanged ) {\n\t\t// If range boundaries have not changed, but there was change inside the range, fire `change:content` event.\n\t\tthis.fire( 'change:content', this.toRange(), { deletionPosition } );\n\t}\n}\n\n// Checks whether given operation changes something inside the range (even if it does not change boundaries).\n//\n// @private\n// @param {module:engine/model/range~Range} range Range to check.\n// @param {module:engine/model/operation/operation~Operation} operation Executed operation.\n// @returns {Boolean}\nfunction doesOperationChangeRangeContent( range, operation ) {\n\tswitch ( operation.type ) {\n\t\tcase 'insert':\n\t\t\treturn range.containsPosition( operation.position );\n\t\tcase 'move':\n\t\tcase 'remove':\n\t\tcase 'reinsert':\n\t\tcase 'merge':\n\t\t\treturn range.containsPosition( operation.sourcePosition ) ||\n\t\t\t\trange.start.isEqual( operation.sourcePosition ) ||\n\t\t\t\trange.containsPosition( operation.targetPosition );\n\t\tcase 'split':\n\t\t\treturn range.containsPosition( operation.splitPosition ) || range.containsPosition( operation.insertionPosition );\n\t}\n\n\treturn false;\n}\n\nmix( LiveRange, EmitterMixin );\n","/**\n * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.\n * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license\n */\n\n/**\n * @module engine/model/documentselection\n */\n\nimport mix from '@ckeditor/ckeditor5-utils/src/mix';\nimport EmitterMixin from '@ckeditor/ckeditor5-utils/src/emittermixin';\n\nimport Selection from './selection';\nimport LiveRange from './liverange';\nimport Text from './text';\nimport TextProxy from './textproxy';\nimport toMap from '@ckeditor/ckeditor5-utils/src/tomap';\nimport Collection from '@ckeditor/ckeditor5-utils/src/collection';\nimport CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';\nimport uid from '@ckeditor/ckeditor5-utils/src/uid';\n\nconst storePrefix = 'selection:';\n\n/**\n * `DocumentSelection` is a special selection which is used as the\n * {@link module:engine/model/document~Document#selection document's selection}.\n * There can be only one instance of `DocumentSelection` per document.\n *\n * Document selection can only be changed by using the {@link module:engine/model/writer~Writer} instance\n * inside the {@link module:engine/model/model~Model#change `change()`} block, as it provides a secure way to modify model.\n *\n * `DocumentSelection` is automatically updated upon changes in the {@link module:engine/model/document~Document document}\n * to always contain valid ranges. Its attributes are inherited from the text unless set explicitly.\n *\n * Differences between {@link module:engine/model/selection~Selection} and `DocumentSelection` are:\n * * there is always a range in `DocumentSelection` - even if no ranges were added there is a \"default range\"\n * present in the selection,\n * * ranges added to this selection updates automatically when the document changes,\n * * attributes of `DocumentSelection` are updated automatically according to selection ranges.\n *\n * Since `DocumentSelection` uses {@link module:engine/model/liverange~LiveRange live ranges}\n * and is updated when {@link module:engine/model/document~Document document}\n * changes, it cannot be set on {@link module:engine/model/node~Node nodes}\n * that are inside {@link module:engine/model/documentfragment~DocumentFragment document fragment}.\n * If you need to represent a selection in document fragment,\n * use {@link module:engine/model/selection~Selection Selection class} instead.\n *\n * @mixes module:utils/emittermixin~EmitterMixin\n */\nexport default class DocumentSelection {\n\t/**\n\t * Creates an empty live selection for given {@link module:engine/model/document~Document}.\n\t *\n\t * @param {module:engine/model/document~Document} doc Document which owns this selection.\n\t */\n\tconstructor( doc ) {\n\t\t/**\n\t\t * Selection used internally by that class (`DocumentSelection` is a proxy to that selection).\n\t\t *\n\t\t * @protected\n\t\t */\n\t\tthis._selection = new LiveSelection( doc );\n\n\t\tthis._selection.delegate( 'change:range' ).to( this );\n\t\tthis._selection.delegate( 'change:attribute' ).to( this );\n\t}\n\n\t/**\n\t * Returns whether the selection is collapsed. Selection is collapsed when there is exactly one range which is\n\t * collapsed.\n\t *\n\t * @readonly\n\t * @type {Boolean}\n\t */\n\tget isCollapsed() {\n\t\treturn this._selection.isCollapsed;\n\t}\n\n\t/**\n\t * Selection anchor. Anchor may be described as a position where the most recent part of the selection starts.\n\t * Together with {@link #focus} they define the direction of selection, which is important\n\t * when expanding/shrinking selection. Anchor is always {@link module:engine/model/range~Range#start start} or\n\t * {@link module:engine/model/range~Range#end end} position of the most recently added range.\n\t *\n\t * Is set to `null` if there are no ranges in selection.\n\t *\n\t * @see #focus\n\t * @readonly\n\t * @type {module:engine/model/position~Position|null}\n\t */\n\tget anchor() {\n\t\treturn this._selection.anchor;\n\t}\n\n\t/**\n\t * Selection focus. Focus is a position where the selection ends.\n\t *\n\t * Is set to `null` if there are no ranges in selection.\n\t *\n\t * @see #anchor\n\t * @readonly\n\t * @type {module:engine/model/position~Position|null}\n\t */\n\tget focus() {\n\t\treturn this._selection.focus;\n\t}\n\n\t/**\n\t * Returns number of ranges in selection.\n\t *\n\t * @readonly\n\t * @type {Number}\n\t */\n\tget rangeCount() {\n\t\treturn this._selection.rangeCount;\n\t}\n\n\t/**\n\t * Describes whether `Documentselection` has own range(s) set, or if it is defaulted to\n\t * {@link module:engine/model/document~Document#_getDefaultRange document's default range}.\n\t *\n\t * @readonly\n\t * @type {Boolean}\n\t */\n\tget hasOwnRange() {\n\t\treturn this._selection.hasOwnRange;\n\t}\n\n\t/**\n\t * Specifies whether the {@link #focus}\n\t * precedes {@link #anchor}.\n\t *\n\t * @readonly\n\t * @type {Boolean}\n\t */\n\tget isBackward() {\n\t\treturn this._selection.isBackward;\n\t}\n\n\t/**\n\t * Describes whether the gravity is overridden (using {@link module:engine/model/writer~Writer#overrideSelectionGravity}) or not.\n\t *\n\t * Note that the gravity remains overridden as long as will not be restored the same number of times as it was overridden.\n\t *\n\t * @readonly\n\t * @returns {Boolean}\n\t */\n\tget isGravityOverridden() {\n\t\treturn this._selection.isGravityOverridden;\n\t}\n\n\t/**\n\t * A collection of selection markers.\n\t * Marker is a selection marker when selection range is inside the marker range.\n\t *\n\t * @readonly\n\t * @type {module:utils/collection~Collection.}\n\t */\n\tget markers() {\n\t\treturn this._selection.markers;\n\t}\n\n\t/**\n\t * Used for the compatibility with the {@link module:engine/model/selection~Selection#isEqual} method.\n\t *\n\t * @protected\n\t */\n\tget _ranges() {\n\t\treturn this._selection._ranges;\n\t}\n\n\t/**\n\t * Returns an iterable that iterates over copies of selection ranges.\n\t *\n\t * @returns {Iterable.}\n\t */\n\tgetRanges() {\n\t\treturn this._selection.getRanges();\n\t}\n\n\t/**\n\t * Returns the first position in the selection.\n\t * First position is the position that {@link module:engine/model/position~Position#isBefore is before}\n\t * any other position in the selection.\n\t *\n\t * Returns `null` if there are no ranges in selection.\n\t *\n\t * @returns {module:engine/model/position~Position|null}\n\t */\n\tgetFirstPosition() {\n\t\treturn this._selection.getFirstPosition();\n\t}\n\n\t/**\n\t * Returns the last position in the selection.\n\t * Last position is the position that {@link module:engine/model/position~Position#isAfter is after}\n\t * any other position in the selection.\n\t *\n\t * Returns `null` if there are no ranges in selection.\n\t *\n\t * @returns {module:engine/model/position~Position|null}\n\t */\n\tgetLastPosition() {\n\t\treturn this._selection.getLastPosition();\n\t}\n\n\t/**\n\t * Returns a copy of the first range in the selection.\n\t * First range is the one which {@link module:engine/model/range~Range#start start} position\n\t * {@link module:engine/model/position~Position#isBefore is before} start position of all other ranges\n\t * (not to confuse with the first range added to the selection).\n\t *\n\t * Returns `null` if there are no ranges in selection.\n\t *\n\t * @returns {module:engine/model/range~Range|null}\n\t */\n\tgetFirstRange() {\n\t\treturn this._selection.getFirstRange();\n\t}\n\n\t/**\n\t * Returns a copy of the last range in the selection.\n\t * Last range is the one which {@link module:engine/model/range~Range#end end} position\n\t * {@link module:engine/model/position~Position#isAfter is after} end position of all other ranges (not to confuse with the range most\n\t * recently added to the selection).\n\t *\n\t * Returns `null` if there are no ranges in selection.\n\t *\n\t * @returns {module:engine/model/range~Range|null}\n\t */\n\tgetLastRange() {\n\t\treturn this._selection.getLastRange();\n\t}\n\n\t/**\n\t * Gets elements of type {@link module:engine/model/schema~Schema#isBlock \"block\"} touched by the selection.\n\t *\n\t * This method's result can be used for example to apply block styling to all blocks covered by this selection.\n\t *\n\t * **Note:** `getSelectedBlocks()` returns blocks that are nested in other non-block elements\n\t * but will not return blocks nested in other blocks.\n\t *\n\t * In this case the function will return exactly all 3 paragraphs (note: `` is not a block itself):\n\t *\n\t *\t\t[a\n\t *\t\t\n\t *\t\t\tb\n\t *\t\t
\n\t *\t\tc]d\n\t *\n\t * In this case the paragraph will also be returned, despite the collapsed selection:\n\t *\n\t *\t\t[]a\n\t *\n\t * In such a scenario, however, only blocks A, B & E will be returned as blocks C & D are nested in block B:\n\t *\n\t *\t\t[\n\t *\t\t\n\t *\t\t\t\n\t *\t\t\t\n\t *\t\t\n\t *\t\t]\n\t *\n\t * If the selection is inside a block all the inner blocks (A & B) are returned:\n\t *\n\t * \t\t\n\t *\t\t\t[a\n\t * \t\t\tb]\n\t * \t\t\n\t *\n\t * **Special case**: If a selection ends at the beginning of a block, that block is not returned as from user perspective\n\t * this block wasn't selected. See [#984](https://github.com/ckeditor/ckeditor5-engine/issues/984) for more details.\n\t *\n\t *\t\t[a\n\t *\t\tb\n\t *\t\t]c // this block will not be returned\n\t *\n\t * @returns {Iterable.}\n\t */\n\tgetSelectedBlocks() {\n\t\treturn this._selection.getSelectedBlocks();\n\t}\n\n\t/**\n\t * Returns the selected element. {@link module:engine/model/element~Element Element} is considered as selected if there is only\n\t * one range in the selection, and that range contains exactly one element.\n\t * Returns `null` if there is no selected element.\n\t *\n\t * @returns {module:engine/model/element~Element|null}\n\t */\n\tgetSelectedElement() {\n\t\treturn this._selection.getSelectedElement();\n\t}\n\n\t/**\n\t * Checks whether the selection contains the entire content of the given element. This means that selection must start\n\t * at a position {@link module:engine/model/position~Position#isTouching touching} the element's start and ends at position\n\t * touching the element's end.\n\t *\n\t * By default, this method will check whether the entire content of the selection's current root is selected.\n\t * Useful to check if e.g. the user has just pressed Ctrl + A.\n\t *\n\t * @param {module:engine/model/element~Element} [element=this.anchor.root]\n\t * @returns {Boolean}\n\t */\n\tcontainsEntireContent( element ) {\n\t\treturn this._selection.containsEntireContent( element );\n\t}\n\n\t/**\n\t * Unbinds all events previously bound by document selection.\n\t */\n\tdestroy() {\n\t\tthis._selection.destroy();\n\t}\n\n\t/**\n\t * Returns iterable that iterates over this selection's attribute keys.\n\t *\n\t * @returns {Iterable.}\n\t */\n\tgetAttributeKeys() {\n\t\treturn this._selection.getAttributeKeys();\n\t}\n\n\t/**\n\t * Returns iterable that iterates over this selection's attributes.\n\t *\n\t * Attributes are returned as arrays containing two items. First one is attribute key and second is attribute value.\n\t * This format is accepted by native `Map` object and also can be passed in `Node` constructor.\n\t *\n\t * @returns {Iterable.<*>}\n\t */\n\tgetAttributes() {\n\t\treturn this._selection.getAttributes();\n\t}\n\n\t/**\n\t * Gets an attribute value for given key or `undefined` if that attribute is not set on the selection.\n\t *\n\t * @param {String} key Key of attribute to look for.\n\t * @returns {*} Attribute value or `undefined`.\n\t */\n\tgetAttribute( key ) {\n\t\treturn this._selection.getAttribute( key );\n\t}\n\n\t/**\n\t * Checks if the selection has an attribute for given key.\n\t *\n\t * @param {String} key Key of attribute to check.\n\t * @returns {Boolean} `true` if attribute with given key is set on selection, `false` otherwise.\n\t */\n\thasAttribute( key ) {\n\t\treturn this._selection.hasAttribute( key );\n\t}\n\n\t/**\n\t * Refreshes selection attributes and markers according to the current position in the model.\n\t */\n\trefresh() {\n\t\tthis._selection._updateMarkers();\n\t\tthis._selection._updateAttributes( false );\n\t}\n\n\t/**\n\t * Checks whether this object is of the given type.\n\t *\n\t *\t\tselection.is( 'selection' ); // -> true\n\t *\t\tselection.is( 'documentSelection' ); // -> true\n\t *\t\tselection.is( 'model:selection' ); // -> true\n\t *\t\tselection.is( 'model:documentSelection' ); // -> true\n\t *\n\t *\t\tselection.is( 'view:selection' ); // -> false\n\t *\t\tselection.is( 'element' ); // -> false\n\t *\t\tselection.is( 'node' ); // -> false\n\t *\n\t * {@link module:engine/model/node~Node#is Check the entire list of model objects} which implement the `is()` method.\n\t *\n\t * @param {String} type\n\t * @returns {Boolean}\n\t */\n\tis( type ) {\n\t\treturn type == 'selection' ||\n\t\t\ttype == 'model:selection' ||\n\t\t\ttype == 'documentSelection' ||\n\t\t\ttype == 'model:documentSelection';\n\t}\n\n\t/**\n\t * Moves {@link module:engine/model/documentselection~DocumentSelection#focus} to the specified location.\n\t * Should be used only within the {@link module:engine/model/writer~Writer#setSelectionFocus} method.\n\t *\n\t * The location can be specified in the same form as\n\t * {@link module:engine/model/writer~Writer#createPositionAt writer.createPositionAt()} parameters.\n\t *\n\t * @see module:engine/model/writer~Writer#setSelectionFocus\n\t * @protected\n\t * @param {module:engine/model/item~Item|module:engine/model/position~Position} itemOrPosition\n\t * @param {Number|'end'|'before'|'after'} [offset] Offset or one of the flags. Used only when\n\t * first parameter is a {@link module:engine/model/item~Item model item}.\n\t */\n\t_setFocus( itemOrPosition, offset ) {\n\t\tthis._selection.setFocus( itemOrPosition, offset );\n\t}\n\n\t/**\n\t * Sets this selection's ranges and direction to the specified location based on the given\n\t * {@link module:engine/model/selection~Selectable selectable}.\n\t * Should be used only within the {@link module:engine/model/writer~Writer#setSelection} method.\n\t *\n\t * @see module:engine/model/writer~Writer#setSelection\n\t * @protected\n\t * @param {module:engine/model/selection~Selectable} selectable\n\t * @param {Number|'before'|'end'|'after'|'on'|'in'} [placeOrOffset] Sets place or offset of the selection.\n\t * @param {Object} [options]\n\t * @param {Boolean} [options.backward] Sets this selection instance to be backward.\n\t */\n\t_setTo( selectable, placeOrOffset, options ) {\n\t\tthis._selection.setTo( selectable, placeOrOffset, options );\n\t}\n\n\t/**\n\t * Sets attribute on the selection. If attribute with the same key already is set, it's value is overwritten.\n\t * Should be used only within the {@link module:engine/model/writer~Writer#setSelectionAttribute} method.\n\t *\n\t * @see module:engine/model/writer~Writer#setSelectionAttribute\n\t * @protected\n\t * @param {String} key Key of the attribute to set.\n\t * @param {*} value Attribute value.\n\t */\n\t_setAttribute( key, value ) {\n\t\tthis._selection.setAttribute( key, value );\n\t}\n\n\t/**\n\t * Removes an attribute with given key from the selection.\n\t * If the given attribute was set on the selection, fires the {@link module:engine/model/selection~Selection#event:change:range}\n\t * event with removed attribute key.\n\t * Should be used only within the {@link module:engine/model/writer~Writer#removeSelectionAttribute} method.\n\t *\n\t * @see module:engine/model/writer~Writer#removeSelectionAttribute\n\t * @protected\n\t * @param {String} key Key of the attribute to remove.\n\t */\n\t_removeAttribute( key ) {\n\t\tthis._selection.removeAttribute( key );\n\t}\n\n\t/**\n\t * Returns an iterable that iterates through all selection attributes stored in current selection's parent.\n\t *\n\t * @protected\n\t * @returns {Iterable.<*>}\n\t */\n\t_getStoredAttributes() {\n\t\treturn this._selection._getStoredAttributes();\n\t}\n\n\t/**\n\t * Temporarily changes the gravity of the selection from the left to the right.\n\t *\n\t * The gravity defines from which direction the selection inherits its attributes. If it's the default left\n\t * gravity, the selection (after being moved by the the user) inherits attributes from its left hand side.\n\t * This method allows to temporarily override this behavior by forcing the gravity to the right.\n\t *\n\t * It returns an unique identifier which is required to restore the gravity. It guarantees the symmetry\n\t * of the process.\n\t *\n\t * @see module:engine/model/writer~Writer#overrideSelectionGravity\n\t * @protected\n\t * @returns {String} The unique id which allows restoring the gravity.\n\t */\n\t_overrideGravity() {\n\t\treturn this._selection.overrideGravity();\n\t}\n\n\t/**\n\t * Restores the {@link ~DocumentSelection#_overrideGravity overridden gravity}.\n\t *\n\t * Restoring the gravity is only possible using the unique identifier returned by\n\t * {@link ~DocumentSelection#_overrideGravity}. Note that the gravity remains overridden as long as won't be restored\n\t * the same number of times it was overridden.\n\t *\n\t * @see module:engine/model/writer~Writer#restoreSelectionGravity\n\t * @protected\n\t * @param {String} uid The unique id returned by {@link #_overrideGravity}.\n\t */\n\t_restoreGravity( uid ) {\n\t\tthis._selection.restoreGravity( uid );\n\t}\n\n\t/**\n\t * Generates and returns an attribute key for selection attributes store, basing on original attribute key.\n\t *\n\t * @protected\n\t * @param {String} key Attribute key to convert.\n\t * @returns {String} Converted attribute key, applicable for selection store.\n\t */\n\tstatic _getStoreAttributeKey( key ) {\n\t\treturn storePrefix + key;\n\t}\n\n\t/**\n\t * Checks whether the given attribute key is an attribute stored on an element.\n\t *\n\t * @protected\n\t * @param {String} key\n\t * @returns {Boolean}\n\t */\n\tstatic _isStoreAttributeKey( key ) {\n\t\treturn key.startsWith( storePrefix );\n\t}\n}\n\nmix( DocumentSelection, EmitterMixin );\n\n/**\n * Fired when selection range(s) changed.\n *\n * @event change:range\n * @param {Boolean} directChange In case of {@link module:engine/model/selection~Selection} class it is always set\n * to `true` which indicates that the selection change was caused by a direct use of selection's API.\n * The {@link module:engine/model/documentselection~DocumentSelection}, however, may change because its position\n * was directly changed through the {@link module:engine/model/writer~Writer writer} or because its position was\n * changed because the structure of the model has been changed (which means an indirect change).\n * The indirect change does not occur in case of normal (detached) selections because they are \"static\" (as \"not live\")\n * which mean that they are not updated once the document changes.\n */\n\n/**\n * Fired when selection attribute changed.\n *\n * @event change:attribute\n * @param {Boolean} directChange In case of {@link module:engine/model/selection~Selection} class it is always set\n * to `true` which indicates that the selection change was caused by a direct use of selection's API.\n * The {@link module:engine/model/documentselection~DocumentSelection}, however, may change because its attributes\n * were directly changed through the {@link module:engine/model/writer~Writer writer} or because its position was\n * changed in the model and its attributes were refreshed (which means an indirect change).\n * The indirect change does not occur in case of normal (detached) selections because they are \"static\" (as \"not live\")\n * which mean that they are not updated once the document changes.\n * @param {Array.} attributeKeys Array containing keys of attributes that changed.\n */\n\n// `LiveSelection` is used internally by {@link module:engine/model/documentselection~DocumentSelection} and shouldn't be used directly.\n//\n// LiveSelection` is automatically updated upon changes in the {@link module:engine/model/document~Document document}\n// to always contain valid ranges. Its attributes are inherited from the text unless set explicitly.\n//\n// Differences between {@link module:engine/model/selection~Selection} and `LiveSelection` are:\n// * there is always a range in `LiveSelection` - even if no ranges were added there is a \"default range\"\n// present in the selection,\n// * ranges added to this selection updates automatically when the document changes,\n// * attributes of `LiveSelection` are updated automatically according to selection ranges.\n//\n// @extends module:engine/model/selection~Selection\n//\n\nclass LiveSelection extends Selection {\n\t// Creates an empty live selection for given {@link module:engine/model/document~Document}.\n\t// @param {module:engine/model/document~Document} doc Document which owns this selection.\n\tconstructor( doc ) {\n\t\tsuper();\n\n\t\t// List of selection markers.\n\t\t// Marker is a selection marker when selection range is inside the marker range.\n\t\t//\n\t\t// @type {module:utils/collection~Collection}\n\t\tthis.markers = new Collection( { idProperty: 'name' } );\n\n\t\t// Document which owns this selection.\n\t\t//\n\t\t// @protected\n\t\t// @member {module:engine/model/model~Model}\n\t\tthis._model = doc.model;\n\n\t\t// Document which owns this selection.\n\t\t//\n\t\t// @protected\n\t\t// @member {module:engine/model/document~Document}\n\t\tthis._document = doc;\n\n\t\t// Keeps mapping of attribute name to priority with which the attribute got modified (added/changed/removed)\n\t\t// last time. Possible values of priority are: `'low'` and `'normal'`.\n\t\t//\n\t\t// Priorities are used by internal `LiveSelection` mechanisms. All attributes set using `LiveSelection`\n\t\t// attributes API are set with `'normal'` priority.\n\t\t//\n\t\t// @private\n\t\t// @member {Map} module:engine/model/liveselection~LiveSelection#_attributePriority\n\t\tthis._attributePriority = new Map();\n\n\t\t// Contains data required to fix ranges which have been moved to the graveyard.\n\t\t// @private\n\t\t// @member {Array} module:engine/model/liveselection~LiveSelection#_fixGraveyardRangesData\n\t\tthis._fixGraveyardRangesData = [];\n\n\t\t// Flag that informs whether the selection ranges have changed. It is changed on true when `LiveRange#change:range` event is fired.\n\t\t// @private\n\t\t// @member {Array} module:engine/model/liveselection~LiveSelection#_hasChangedRange\n\t\tthis._hasChangedRange = false;\n\n\t\t// Each overriding gravity adds an UID to the set and each removal removes it.\n\t\t// Gravity is overridden when there's at least one UID in the set.\n\t\t// Gravity is restored when the set is empty.\n\t\t// This is to prevent conflicts when gravity is overridden by more than one feature at the same time.\n\t\t// @private\n\t\t// @type {Set}\n\t\tthis._overriddenGravityRegister = new Set();\n\n\t\t// Ensure selection is correct after each operation.\n\t\tthis.listenTo( this._model, 'applyOperation', ( evt, args ) => {\n\t\t\tconst operation = args[ 0 ];\n\n\t\t\tif ( !operation.isDocumentOperation || operation.type == 'marker' || operation.type == 'rename' || operation.type == 'noop' ) {\n\t\t\t\treturn;\n\t\t\t}\n\n\t\t\twhile ( this._fixGraveyardRangesData.length ) {\n\t\t\t\tconst { liveRange, sourcePosition } = this._fixGraveyardRangesData.shift();\n\n\t\t\t\tthis._fixGraveyardSelection( liveRange, sourcePosition );\n\t\t\t}\n\n\t\t\tif ( this._hasChangedRange ) {\n\t\t\t\tthis._hasChangedRange = false;\n\t\t\t\tthis.fire( 'change:range', { directChange: false } );\n\t\t\t}\n\t\t}, { priority: 'lowest' } );\n\n\t\t// Ensure selection is correct and up to date after each range change.\n\t\tthis.on( 'change:range', () => {\n\t\t\tfor ( const range of this.getRanges() ) {\n\t\t\t\tif ( !this._document._validateSelectionRange( range ) ) {\n\t\t\t\t\t/**\n\t\t\t\t\t * Range from {@link module:engine/model/documentselection~DocumentSelection document selection}\n\t\t\t\t\t * starts or ends at incorrect position.\n\t\t\t\t\t *\n\t\t\t\t\t * @error document-selection-wrong-position\n\t\t\t\t\t * @param {module:engine/model/range~Range} range\n\t\t\t\t\t */\n\t\t\t\t\tthrow new CKEditorError(\n\t\t\t\t\t\t'document-selection-wrong-position: Range from document selection starts or ends at incorrect position.',\n\t\t\t\t\t\tthis,\n\t\t\t\t\t\t{ range }\n\t\t\t\t\t);\n\t\t\t\t}\n\t\t\t}\n\t\t} );\n\n\t\t// Update markers data stored by the selection after each marker change.\n\t\tthis.listenTo( this._model.markers, 'update', () => this._updateMarkers() );\n\n\t\t// Ensure selection is up to date after each change block.\n\t\tthis.listenTo( this._document, 'change', ( evt, batch ) => {\n\t\t\tclearAttributesStoredInElement( this._model, batch );\n\t\t} );\n\t}\n\n\tget isCollapsed() {\n\t\tconst length = this._ranges.length;\n\n\t\treturn length === 0 ? this._document._getDefaultRange().isCollapsed : super.isCollapsed;\n\t}\n\n\tget anchor() {\n\t\treturn super.anchor || this._document._getDefaultRange().start;\n\t}\n\n\tget focus() {\n\t\treturn super.focus || this._document._getDefaultRange().end;\n\t}\n\n\tget rangeCount() {\n\t\treturn this._ranges.length ? this._ranges.length : 1;\n\t}\n\n\t// Describes whether `LiveSelection` has own range(s) set, or if it is defaulted to\n\t// {@link module:engine/model/document~Document#_getDefaultRange document's default range}.\n\t//\n\t// @readonly\n\t// @type {Boolean}\n\tget hasOwnRange() {\n\t\treturn this._ranges.length > 0;\n\t}\n\n\t// When set to `true` then selection attributes on node before the caret won't be taken\n\t// into consideration while updating selection attributes.\n\t//\n\t// @protected\n\t// @type {Boolean}\n\tget isGravityOverridden() {\n\t\treturn !!this._overriddenGravityRegister.size;\n\t}\n\n\t// Unbinds all events previously bound by live selection.\n\tdestroy() {\n\t\tfor ( let i = 0; i < this._ranges.length; i++ ) {\n\t\t\tthis._ranges[ i ].detach();\n\t\t}\n\n\t\tthis.stopListening();\n\t}\n\n\t* getRanges() {\n\t\tif ( this._ranges.length ) {\n\t\t\tyield* super.getRanges();\n\t\t} else {\n\t\t\tyield this._document._getDefaultRange();\n\t\t}\n\t}\n\n\tgetFirstRange() {\n\t\treturn super.getFirstRange() || this._document._getDefaultRange();\n\t}\n\n\tgetLastRange() {\n\t\treturn super.getLastRange() || this._document._getDefaultRange();\n\t}\n\n\tsetTo( selectable, optionsOrPlaceOrOffset, options ) {\n\t\tsuper.setTo( selectable, optionsOrPlaceOrOffset, options );\n\t\tthis._updateAttributes( true );\n\t}\n\n\tsetFocus( itemOrPosition, offset ) {\n\t\tsuper.setFocus( itemOrPosition, offset );\n\t\tthis._updateAttributes( true );\n\t}\n\n\tsetAttribute( key, value ) {\n\t\tif ( this._setAttribute( key, value ) ) {\n\t\t\t// Fire event with exact data.\n\t\t\tconst attributeKeys = [ key ];\n\t\t\tthis.fire( 'change:attribute', { attributeKeys, directChange: true } );\n\t\t}\n\t}\n\n\tremoveAttribute( key ) {\n\t\tif ( this._removeAttribute( key ) ) {\n\t\t\t// Fire event with exact data.\n\t\t\tconst attributeKeys = [ key ];\n\t\t\tthis.fire( 'change:attribute', { attributeKeys, directChange: true } );\n\t\t}\n\t}\n\n\toverrideGravity() {\n\t\tconst overrideUid = uid();\n\n\t\t// Remember that another overriding has been requested. It will need to be removed\n\t\t// before the gravity is to be restored.\n\t\tthis._overriddenGravityRegister.add( overrideUid );\n\n\t\tif ( this._overriddenGravityRegister.size === 1 ) {\n\t\t\tthis._updateAttributes( true );\n\t\t}\n\n\t\treturn overrideUid;\n\t}\n\n\trestoreGravity( uid ) {\n\t\tif ( !this._overriddenGravityRegister.has( uid ) ) {\n\t\t\t/**\n\t\t\t * Restoring gravity for an unknown UID is not possible. Make sure you are using a correct\n\t\t\t * UID obtained from the {@link module:engine/model/writer~Writer#overrideSelectionGravity} to restore.\n\t\t\t *\n\t\t\t * @error document-selection-gravity-wrong-restore\n\t\t\t * @param {String} uid The unique identifier returned by\n\t\t\t * {@link module:engine/model/documentselection~DocumentSelection#_overrideGravity}.\n\t\t\t */\n\t\t\tthrow new CKEditorError(\n\t\t\t\t'document-selection-gravity-wrong-restore: Attempting to restore the selection gravity for an unknown UID.',\n\t\t\t\tthis,\n\t\t\t\t{ uid }\n\t\t\t);\n\t\t}\n\n\t\tthis._overriddenGravityRegister.delete( uid );\n\n\t\t// Restore gravity only when all overriding have been restored.\n\t\tif ( !this.isGravityOverridden ) {\n\t\t\tthis._updateAttributes( true );\n\t\t}\n\t}\n\n\t_popRange() {\n\t\tthis._ranges.pop().detach();\n\t}\n\n\t_pushRange( range ) {\n\t\tconst liveRange = this._prepareRange( range );\n\n\t\t// `undefined` is returned when given `range` is in graveyard root.\n\t\tif ( liveRange ) {\n\t\t\tthis._ranges.push( liveRange );\n\t\t}\n\t}\n\n\t// Prepares given range to be added to selection. Checks if it is correct,\n\t// converts it to {@link module:engine/model/liverange~LiveRange LiveRange}\n\t// and sets listeners listening to the range's change event.\n\t//\n\t// @private\n\t// @param {module:engine/model/range~Range} range\n\t_prepareRange( range ) {\n\t\tthis._checkRange( range );\n\n\t\tif ( range.root == this._document.graveyard ) {\n\t\t\t// @if CK_DEBUG // console.warn( 'Trying to add a Range that is in the graveyard root. Range rejected.' );\n\n\t\t\treturn;\n\t\t}\n\n\t\tconst liveRange = LiveRange.fromRange( range );\n\n\t\tliveRange.on( 'change:range', ( evt, oldRange, data ) => {\n\t\t\tthis._hasChangedRange = true;\n\n\t\t\t// If `LiveRange` is in whole moved to the graveyard, save necessary data. It will be fixed on `Model#applyOperation` event.\n\t\t\tif ( liveRange.root == this._document.graveyard ) {\n\t\t\t\tthis._fixGraveyardRangesData.push( {\n\t\t\t\t\tliveRange,\n\t\t\t\t\tsourcePosition: data.deletionPosition\n\t\t\t\t} );\n\t\t\t}\n\t\t} );\n\n\t\treturn liveRange;\n\t}\n\n\t_updateMarkers() {\n\t\tconst markers = [];\n\n\t\tfor ( const marker of this._model.markers ) {\n\t\t\tconst markerRange = marker.getRange();\n\n\t\t\tfor ( const selectionRange of this.getRanges() ) {\n\t\t\t\tif ( markerRange.containsRange( selectionRange, !selectionRange.isCollapsed ) ) {\n\t\t\t\t\tmarkers.push( marker );\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\n\t\tfor ( const marker of markers ) {\n\t\t\tif ( !this.markers.has( marker ) ) {\n\t\t\t\tthis.markers.add( marker );\n\t\t\t}\n\t\t}\n\n\t\tfor ( const marker of Array.from( this.markers ) ) {\n\t\t\tif ( !markers.includes( marker ) ) {\n\t\t\t\tthis.markers.remove( marker );\n\t\t\t}\n\t\t}\n\t}\n\n\t// Updates this selection attributes according to its ranges and the {@link module:engine/model/document~Document model document}.\n\t//\n\t// @protected\n\t// @param {Boolean} clearAll\n\t// @fires change:attribute\n\t_updateAttributes( clearAll ) {\n\t\tconst newAttributes = toMap( this._getSurroundingAttributes() );\n\t\tconst oldAttributes = toMap( this.getAttributes() );\n\n\t\tif ( clearAll ) {\n\t\t\t// If `clearAll` remove all attributes and reset priorities.\n\t\t\tthis._attributePriority = new Map();\n\t\t\tthis._attrs = new Map();\n\t\t} else {\n\t\t\t// If not, remove only attributes added with `low` priority.\n\t\t\tfor ( const [ key, priority ] of this._attributePriority ) {\n\t\t\t\tif ( priority == 'low' ) {\n\t\t\t\t\tthis._attrs.delete( key );\n\t\t\t\t\tthis._attributePriority.delete( key );\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\n\t\tthis._setAttributesTo( newAttributes );\n\n\t\t// Let's evaluate which attributes really changed.\n\t\tconst changed = [];\n\n\t\t// First, loop through all attributes that are set on selection right now.\n\t\t// Check which of them are different than old attributes.\n\t\tfor ( const [ newKey, newValue ] of this.getAttributes() ) {\n\t\t\tif ( !oldAttributes.has( newKey ) || oldAttributes.get( newKey ) !== newValue ) {\n\t\t\t\tchanged.push( newKey );\n\t\t\t}\n\t\t}\n\n\t\t// Then, check which of old attributes got removed.\n\t\tfor ( const [ oldKey ] of oldAttributes ) {\n\t\t\tif ( !this.hasAttribute( oldKey ) ) {\n\t\t\t\tchanged.push( oldKey );\n\t\t\t}\n\t\t}\n\n\t\t// Fire event with exact data (fire only if anything changed).\n\t\tif ( changed.length > 0 ) {\n\t\t\tthis.fire( 'change:attribute', { attributeKeys: changed, directChange: false } );\n\t\t}\n\t}\n\n\t// Internal method for setting `LiveSelection` attribute. Supports attribute priorities (through `directChange`\n\t// parameter).\n\t//\n\t// @private\n\t// @param {String} key Attribute key.\n\t// @param {*} value Attribute value.\n\t// @param {Boolean} [directChange=true] `true` if the change is caused by `Selection` API, `false` if change\n\t// is caused by `Batch` API.\n\t// @returns {Boolean} Whether value has changed.\n\t_setAttribute( key, value, directChange = true ) {\n\t\tconst priority = directChange ? 'normal' : 'low';\n\n\t\tif ( priority == 'low' && this._attributePriority.get( key ) == 'normal' ) {\n\t\t\t// Priority too low.\n\t\t\treturn false;\n\t\t}\n\n\t\tconst oldValue = super.getAttribute( key );\n\n\t\t// Don't do anything if value has not changed.\n\t\tif ( oldValue === value ) {\n\t\t\treturn false;\n\t\t}\n\n\t\tthis._attrs.set( key, value );\n\n\t\t// Update priorities map.\n\t\tthis._attributePriority.set( key, priority );\n\n\t\treturn true;\n\t}\n\n\t// Internal method for removing `LiveSelection` attribute. Supports attribute priorities (through `directChange`\n\t// parameter).\n\t//\n\t// NOTE: Even if attribute is not present in the selection but is provided to this method, it's priority will\n\t// be changed according to `directChange` parameter.\n\t//\n\t// @private\n\t// @param {String} key Attribute key.\n\t// @param {Boolean} [directChange=true] `true` if the change is caused by `Selection` API, `false` if change\n\t// is caused by `Batch` API.\n\t// @returns {Boolean} Whether attribute was removed. May not be true if such attributes didn't exist or the\n\t// existing attribute had higher priority.\n\t_removeAttribute( key, directChange = true ) {\n\t\tconst priority = directChange ? 'normal' : 'low';\n\n\t\tif ( priority == 'low' && this._attributePriority.get( key ) == 'normal' ) {\n\t\t\t// Priority too low.\n\t\t\treturn false;\n\t\t}\n\n\t\t// Update priorities map.\n\t\tthis._attributePriority.set( key, priority );\n\n\t\t// Don't do anything if value has not changed.\n\t\tif ( !super.hasAttribute( key ) ) {\n\t\t\treturn false;\n\t\t}\n\n\t\tthis._attrs.delete( key );\n\n\t\treturn true;\n\t}\n\n\t// Internal method for setting multiple `LiveSelection` attributes. Supports attribute priorities (through\n\t// `directChange` parameter).\n\t//\n\t// @private\n\t// @param {Map.} attrs Iterable object containing attributes to be set.\n\t// @returns {Set.} Changed attribute keys.\n\t_setAttributesTo( attrs ) {\n\t\tconst changed = new Set();\n\n\t\tfor ( const [ oldKey, oldValue ] of this.getAttributes() ) {\n\t\t\t// Do not remove attribute if attribute with same key and value is about to be set.\n\t\t\tif ( attrs.get( oldKey ) === oldValue ) {\n\t\t\t\tcontinue;\n\t\t\t}\n\n\t\t\t// All rest attributes will be removed so changed attributes won't change .\n\t\t\tthis._removeAttribute( oldKey, false );\n\t\t}\n\n\t\tfor ( const [ key, value ] of attrs ) {\n\t\t\t// Attribute may not be set because of attributes or because same key/value is already added.\n\t\t\tconst gotAdded = this._setAttribute( key, value, false );\n\n\t\t\tif ( gotAdded ) {\n\t\t\t\tchanged.add( key );\n\t\t\t}\n\t\t}\n\n\t\treturn changed;\n\t}\n\n\t// Returns an iterable that iterates through all selection attributes stored in current selection's parent.\n\t//\n\t// @protected\n\t// @returns {Iterable.<*>}\n\t* _getStoredAttributes() {\n\t\tconst selectionParent = this.getFirstPosition().parent;\n\n\t\tif ( this.isCollapsed && selectionParent.isEmpty ) {\n\t\t\tfor ( const key of selectionParent.getAttributeKeys() ) {\n\t\t\t\tif ( key.startsWith( storePrefix ) ) {\n\t\t\t\t\tconst realKey = key.substr( storePrefix.length );\n\n\t\t\t\t\tyield [ realKey, selectionParent.getAttribute( key ) ];\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\t}\n\n\t// Checks model text nodes that are closest to the selection's first position and returns attributes of first\n\t// found element. If there are no text nodes in selection's first position parent, it returns selection\n\t// attributes stored in that parent.\n\t//\n\t// @private\n\t// @returns {Iterable.<*>} Collection of attributes.\n\t_getSurroundingAttributes() {\n\t\tconst position = this.getFirstPosition();\n\t\tconst schema = this._model.schema;\n\n\t\tlet attrs = null;\n\n\t\tif ( !this.isCollapsed ) {\n\t\t\t// 1. If selection is a range...\n\t\t\tconst range = this.getFirstRange();\n\n\t\t\t// ...look for a first character node in that range and take attributes from it.\n\t\t\tfor ( const value of range ) {\n\t\t\t\t// If the item is an object, we don't want to get attributes from its children.\n\t\t\t\tif ( value.item.is( 'element' ) && schema.isObject( value.item ) ) {\n\t\t\t\t\tbreak;\n\t\t\t\t}\n\n\t\t\t\tif ( value.type == 'text' ) {\n\t\t\t\t\tattrs = value.item.getAttributes();\n\t\t\t\t\tbreak;\n\t\t\t\t}\n\t\t\t}\n\t\t} else {\n\t\t\t// 2. If the selection is a caret or the range does not contain a character node...\n\n\t\t\tconst nodeBefore = position.textNode ? position.textNode : position.nodeBefore;\n\t\t\tconst nodeAfter = position.textNode ? position.textNode : position.nodeAfter;\n\n\t\t\t// When gravity is overridden then don't take node before into consideration.\n\t\t\tif ( !this.isGravityOverridden ) {\n\t\t\t\t// ...look at the node before caret and take attributes from it if it is a character node.\n\t\t\t\tattrs = getAttrsIfCharacter( nodeBefore );\n\t\t\t}\n\n\t\t\t// 3. If not, look at the node after caret...\n\t\t\tif ( !attrs ) {\n\t\t\t\tattrs = getAttrsIfCharacter( nodeAfter );\n\t\t\t}\n\n\t\t\t// 4. If not, try to find the first character on the left, that is in the same node.\n\t\t\t// When gravity is overridden then don't take node before into consideration.\n\t\t\tif ( !this.isGravityOverridden && !attrs ) {\n\t\t\t\tlet node = nodeBefore;\n\n\t\t\t\twhile ( node && !attrs ) {\n\t\t\t\t\tnode = node.previousSibling;\n\t\t\t\t\tattrs = getAttrsIfCharacter( node );\n\t\t\t\t}\n\t\t\t}\n\n\t\t\t// 5. If not found, try to find the first character on the right, that is in the same node.\n\t\t\tif ( !attrs ) {\n\t\t\t\tlet node = nodeAfter;\n\n\t\t\t\twhile ( node && !attrs ) {\n\t\t\t\t\tnode = node.nextSibling;\n\t\t\t\t\tattrs = getAttrsIfCharacter( node );\n\t\t\t\t}\n\t\t\t}\n\n\t\t\t// 6. If not found, selection should retrieve attributes from parent.\n\t\t\tif ( !attrs ) {\n\t\t\t\tattrs = this._getStoredAttributes();\n\t\t\t}\n\t\t}\n\n\t\treturn attrs;\n\t}\n\n\t// Fixes a selection range after it ends up in graveyard root.\n\t//\n\t// @private\n\t// @param {module:engine/model/liverange~LiveRange} liveRange The range from selection, that ended up in the graveyard root.\n\t// @param {module:engine/model/position~Position} removedRangeStart Start position of a range which was removed.\n\t_fixGraveyardSelection( liveRange, removedRangeStart ) {\n\t\t// The start of the removed range is the closest position to the `liveRange` - the original selection range.\n\t\t// This is a good candidate for a fixed selection range.\n\t\tconst positionCandidate = removedRangeStart.clone();\n\n\t\t// Find a range that is a correct selection range and is closest to the start of removed range.\n\t\tconst selectionRange = this._model.schema.getNearestSelectionRange( positionCandidate );\n\n\t\t// Remove the old selection range before preparing and adding new selection range. This order is important,\n\t\t// because new range, in some cases, may intersect with old range (it depends on `getNearestSelectionRange()` result).\n\t\tconst index = this._ranges.indexOf( liveRange );\n\t\tthis._ranges.splice( index, 1 );\n\t\tliveRange.detach();\n\n\t\t// If nearest valid selection range has been found - add it in the place of old range.\n\t\tif ( selectionRange ) {\n\t\t\t// Check the range, convert it to live range, bind events, etc.\n\t\t\tconst newRange = this._prepareRange( selectionRange );\n\n\t\t\t// Add new range in the place of old range.\n\t\t\tthis._ranges.splice( index, 0, newRange );\n\t\t}\n\t\t// If nearest valid selection range cannot be found - just removing the old range is fine.\n\t}\n}\n\n// Helper function for {@link module:engine/model/liveselection~LiveSelection#_updateAttributes}.\n//\n// It takes model item, checks whether it is a text node (or text proxy) and, if so, returns it's attributes. If not, returns `null`.\n//\n// @param {module:engine/model/item~Item|null} node\n// @returns {Boolean}\nfunction getAttrsIfCharacter( node ) {\n\tif ( node instanceof TextProxy || node instanceof Text ) {\n\t\treturn node.getAttributes();\n\t}\n\n\treturn null;\n}\n\n// Removes selection attributes from element which is not empty anymore.\n//\n// @private\n// @param {module:engine/model/model~Model} model\n// @param {module:engine/model/batch~Batch} batch\nfunction clearAttributesStoredInElement( model, batch ) {\n\tconst differ = model.document.differ;\n\n\tfor ( const entry of differ.getChanges() ) {\n\t\tif ( entry.type != 'insert' ) {\n\t\t\tcontinue;\n\t\t}\n\n\t\tconst changeParent = entry.position.parent;\n\t\tconst isNoLongerEmpty = entry.length === changeParent.maxOffset;\n\n\t\tif ( isNoLongerEmpty ) {\n\t\t\tmodel.enqueueChange( batch, writer => {\n\t\t\t\tconst storedAttributes = Array.from( changeParent.getAttributeKeys() )\n\t\t\t\t\t.filter( key => key.startsWith( storePrefix ) );\n\n\t\t\t\tfor ( const key of storedAttributes ) {\n\t\t\t\t\twriter.removeAttribute( key, changeParent );\n\t\t\t\t}\n\t\t\t} );\n\t\t}\n\t}\n}\n","/**\n * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.\n * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license\n */\n\n/**\n * @module engine/conversion/conversionhelpers\n */\n\n/**\n * Base class for conversion helpers.\n */\nexport default class ConversionHelpers {\n\t/**\n\t * Creates a conversion helpers instance.\n\t *\n\t * @param {Array.} dispatchers\n\t */\n\tconstructor( dispatchers ) {\n\t\tthis._dispatchers = dispatchers;\n\t}\n\n\t/**\n\t * Registers a conversion helper.\n\t *\n\t * **Note**: See full usage example in the `{@link module:engine/conversion/conversion~Conversion#for conversion.for()}`\n\t * method description.\n\t *\n\t * @param {Function} conversionHelper The function to be called on event.\n\t * @returns {module:engine/conversion/downcasthelpers~DowncastHelpers|module:engine/conversion/upcasthelpers~UpcastHelpers}\n\t */\n\tadd( conversionHelper ) {\n\t\tfor ( const dispatcher of this._dispatchers ) {\n\t\t\tconversionHelper( dispatcher );\n\t\t}\n\n\t\treturn this;\n\t}\n}\n","import baseClone from './_baseClone.js';\n\n/** Used to compose bitmasks for cloning. */\nvar CLONE_DEEP_FLAG = 1,\n CLONE_SYMBOLS_FLAG = 4;\n\n/**\n * This method is like `_.clone` except that it recursively clones `value`.\n *\n * @static\n * @memberOf _\n * @since 1.0.0\n * @category Lang\n * @param {*} value The value to recursively clone.\n * @returns {*} Returns the deep cloned value.\n * @see _.clone\n * @example\n *\n * var objects = [{ 'a': 1 }, { 'b': 2 }];\n *\n * var deep = _.cloneDeep(objects);\n * console.log(deep[0] === objects[0]);\n * // => false\n */\nfunction cloneDeep(value) {\n return baseClone(value, CLONE_DEEP_FLAG | CLONE_SYMBOLS_FLAG);\n}\n\nexport default cloneDeep;\n","/**\n * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.\n * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license\n */\n\n/**\n * Contains downcast (model-to-view) converters for {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher}.\n *\n * @module engine/conversion/downcasthelpers\n */\n\nimport ModelRange from '../model/range';\nimport ModelSelection from '../model/selection';\nimport ModelElement from '../model/element';\n\nimport ViewAttributeElement from '../view/attributeelement';\nimport DocumentSelection from '../model/documentselection';\nimport ConversionHelpers from './conversionhelpers';\n\nimport { cloneDeep } from 'lodash-es';\nimport CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';\n\n/**\n * Downcast conversion helper functions.\n *\n * @extends module:engine/conversion/conversionhelpers~ConversionHelpers\n */\nexport default class DowncastHelpers extends ConversionHelpers {\n\t/**\n\t * Model element to view element conversion helper.\n\t *\n\t * This conversion results in creating a view element. For example, model `Foo` becomes `Foo
` in the view.\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).elementToElement( {\n\t *\t\t\tmodel: 'paragraph',\n\t *\t\t\tview: 'p'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).elementToElement( {\n\t *\t\t\tmodel: 'paragraph',\n\t *\t\t\tview: 'div',\n\t *\t\t\tconverterPriority: 'high'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).elementToElement( {\n\t *\t\t\tmodel: 'fancyParagraph',\n\t *\t\t\tview: {\n\t *\t\t\t\tname: 'p',\n\t *\t\t\t\tclasses: 'fancy'\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).elementToElement( {\n\t *\t\t\tmodel: 'heading',\n\t *\t\t\tview: ( modelElement, viewWriter ) => {\n\t *\t\t\t\treturn viewWriter.createContainerElement( 'h' + modelElement.getAttribute( 'level' ) )\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t * See {@link module:engine/conversion/conversion~Conversion#for `conversion.for()`} to learn how to add a converter\n\t * to the conversion process.\n\t *\n\t * @method #elementToElement\n\t * @param {Object} config Conversion configuration.\n\t * @param {String} config.model The name of the model element to convert.\n\t * @param {module:engine/view/elementdefinition~ElementDefinition|Function} config.view A view element definition or a function\n\t * that takes the model element and {@link module:engine/view/downcastwriter~DowncastWriter view downcast writer}\n\t * as parameters and returns a view container element.\n\t * @returns {module:engine/conversion/downcasthelpers~DowncastHelpers}\n\t */\n\telementToElement( config ) {\n\t\treturn this.add( downcastElementToElement( config ) );\n\t}\n\n\t/**\n\t * Model attribute to view element conversion helper.\n\t *\n\t * This conversion results in wrapping view nodes with a view attribute element. For example, a model text node with\n\t * `\"Foo\"` as data and the `bold` attribute becomes `Foo` in the view.\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToElement( {\n\t *\t\t\tmodel: 'bold',\n\t *\t\t\tview: 'strong'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToElement( {\n\t *\t\t\tmodel: 'bold',\n\t *\t\t\tview: 'b',\n\t *\t\t\tconverterPriority: 'high'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToElement( {\n\t *\t\t\tmodel: 'invert',\n\t *\t\t\tview: {\n\t *\t\t\t\tname: 'span',\n\t *\t\t\t\tclasses: [ 'font-light', 'bg-dark' ]\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToElement( {\n\t *\t\t\tmodel: {\n\t *\t\t\t\tkey: 'fontSize',\n\t *\t\t\t\tvalues: [ 'big', 'small' ]\n\t *\t\t\t},\n\t *\t\t\tview: {\n\t *\t\t\t\tbig: {\n\t *\t\t\t\t\tname: 'span',\n\t *\t\t\t\t\tstyles: {\n\t *\t\t\t\t\t\t'font-size': '1.2em'\n\t *\t\t\t\t\t}\n\t *\t\t\t\t},\n\t *\t\t\t\tsmall: {\n\t *\t\t\t\t\tname: 'span',\n\t *\t\t\t\t\tstyles: {\n\t *\t\t\t\t\t\t'font-size': '0.8em'\n\t *\t\t\t\t\t}\n\t *\t\t\t\t}\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToElement( {\n\t *\t\t\tmodel: 'bold',\n\t *\t\t\tview: ( modelAttributeValue, viewWriter ) => {\n\t *\t\t\t\treturn viewWriter.createAttributeElement( 'span', {\n\t *\t\t\t\t\tstyle: 'font-weight:' + modelAttributeValue\n\t *\t\t\t\t} );\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToElement( {\n\t *\t\t\tmodel: {\n\t *\t\t\t\tkey: 'color',\n\t *\t\t\t\tname: '$text'\n\t *\t\t\t},\n\t *\t\t\tview: ( modelAttributeValue, viewWriter ) => {\n\t *\t\t\t\treturn viewWriter.createAttributeElement( 'span', {\n\t *\t\t\t\t\tstyle: 'color:' + modelAttributeValue\n\t *\t\t\t\t} );\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t * See {@link module:engine/conversion/conversion~Conversion#for `conversion.for()`} to learn how to add a converter\n\t * to the conversion process.\n\t *\n\t * @method #attributeToElement\n\t * @param {Object} config Conversion configuration.\n\t * @param {String|Object} config.model The key of the attribute to convert from or a `{ key, values }` object. `values` is an array\n\t * of `String`s with possible values if the model attribute is an enumerable.\n\t * @param {module:engine/view/elementdefinition~ElementDefinition|Function|Object} config.view A view element definition or a function\n\t * that takes the model attribute value and {@link module:engine/view/downcastwriter~DowncastWriter view downcast writer}\n\t * as parameters and returns a view attribute element. If `config.model.values` is\n\t * given, `config.view` should be an object assigning values from `config.model.values` to view element definitions or functions.\n\t * @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n\t * @returns {module:engine/conversion/downcasthelpers~DowncastHelpers}\n\t */\n\tattributeToElement( config ) {\n\t\treturn this.add( downcastAttributeToElement( config ) );\n\t}\n\n\t/**\n\t * Model attribute to view attribute conversion helper.\n\t *\n\t * This conversion results in adding an attribute to a view node, basing on an attribute from a model node. For example,\n\t * `` is converted to `
`.\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToAttribute( {\n\t *\t\t\tmodel: 'source',\n\t *\t\t\tview: 'src'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToAttribute( {\n\t *\t\t\tmodel: 'source',\n\t *\t\t\tview: 'href',\n\t *\t\t\tconverterPriority: 'high'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToAttribute( {\n\t *\t\t\tmodel: {\n\t *\t\t\t\tname: 'image',\n\t *\t\t\t\tkey: 'source'\n\t *\t\t\t},\n\t *\t\t\tview: 'src'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToAttribute( {\n\t *\t\t\tmodel: {\n\t *\t\t\t\tname: 'styled',\n\t *\t\t\t\tvalues: [ 'dark', 'light' ]\n\t *\t\t\t},\n\t *\t\t\tview: {\n\t *\t\t\t\tdark: {\n\t *\t\t\t\t\tkey: 'class',\n\t *\t\t\t\t\tvalue: [ 'styled', 'styled-dark' ]\n\t *\t\t\t\t},\n\t *\t\t\t\tlight: {\n\t *\t\t\t\t\tkey: 'class',\n\t *\t\t\t\t\tvalue: [ 'styled', 'styled-light' ]\n\t *\t\t\t\t}\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToAttribute( {\n\t *\t\t\tmodel: 'styled',\n\t *\t\t\tview: modelAttributeValue => ( { key: 'class', value: 'styled-' + modelAttributeValue } )\n\t *\t\t} );\n\t *\n\t * *Note:* Downcasting to a style property requires providing `value` as an object:\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).attributeToAttribute( {\n\t *\t\t\tmodel: 'lineHeight',\n\t *\t\t\tview: modelAttributeValue => ( {\n\t *\t\t\t\tkey: 'style',\n\t *\t\t\t\tvalue: {\n\t *\t\t\t\t\t'line-height': modelAttributeValue,\n\t *\t\t\t\t\t'border-bottom': '1px dotted #ba2'\n\t *\t\t\t\t}\n\t *\t\t\t} )\n\t *\t\t} );\n\t *\n\t * See {@link module:engine/conversion/conversion~Conversion#for `conversion.for()`} to learn how to add a converter\n\t * to the conversion process.\n\t *\n\t * @method #attributeToAttribute\n\t * @param {Object} config Conversion configuration.\n\t * @param {String|Object} config.model The key of the attribute to convert from or a `{ key, values, [ name ] }` object describing\n\t * the attribute key, possible values and, optionally, an element name to convert from.\n\t * @param {String|Object|Function} config.view A view attribute key, or a `{ key, value }` object or a function that takes\n\t * the model attribute value and returns a `{ key, value }` object. If `key` is `'class'`, `value` can be a `String` or an\n\t * array of `String`s. If `key` is `'style'`, `value` is an object with key-value pairs. In other cases, `value` is a `String`.\n\t * If `config.model.values` is set, `config.view` should be an object assigning values from `config.model.values` to\n\t * `{ key, value }` objects or a functions.\n\t * @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n\t * @returns {module:engine/conversion/downcasthelpers~DowncastHelpers}\n\t */\n\tattributeToAttribute( config ) {\n\t\treturn this.add( downcastAttributeToAttribute( config ) );\n\t}\n\n\t/**\n\t * Model marker to view element conversion helper.\n\t *\n\t * This conversion results in creating a view element on the boundaries of the converted marker. If the converted marker\n\t * is collapsed, only one element is created. For example, model marker set like this: `F[oo b]ar`\n\t * becomes `Foo bar
` in the view.\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).markerToElement( {\n\t *\t\t\tmodel: 'search',\n\t *\t\t\tview: 'marker-search'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).markerToElement( {\n\t *\t\t\tmodel: 'search',\n\t *\t\t\tview: 'search-result',\n\t *\t\t\tconverterPriority: 'high'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).markerToElement( {\n\t *\t\t\tmodel: 'search',\n\t *\t\t\tview: {\n\t *\t\t\t\tname: 'span',\n\t *\t\t\t\tattributes: {\n\t *\t\t\t\t\t'data-marker': 'search'\n\t *\t\t\t\t}\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).markerToElement( {\n\t *\t\t\tmodel: 'search',\n\t *\t\t\tview: ( markerData, viewWriter ) => {\n\t *\t\t\t\treturn viewWriter.createUIElement( 'span', {\n\t *\t\t\t\t\t'data-marker': 'search',\n\t *\t\t\t\t\t'data-start': markerData.isOpening\n\t *\t\t\t\t} );\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t * If a function is passed as the `config.view` parameter, it will be used to generate both boundary elements. The function\n\t * receives the `data` object as a parameter and should return an instance of the\n\t * {@link module:engine/view/uielement~UIElement view UI element}. The `data` object and\n\t * {@link module:engine/conversion/downcastdispatcher~DowncastConversionApi `conversionApi`} are passed from\n\t * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:addMarker}. Additionally,\n\t * the `data.isOpening` parameter is passed, which is set to `true` for the marker start boundary element, and `false` to\n\t * the marker end boundary element.\n\t *\n\t * This kind of conversion is useful for saving data into the database, so it should be used in the data conversion pipeline.\n\t *\n\t * See {@link module:engine/conversion/conversion~Conversion#for `conversion.for()`} to learn how to add a converter\n\t * to the conversion process.\n\t *\n\t * @method #markerToElement\n\t * @param {Object} config Conversion configuration.\n\t * @param {String} config.model The name of the model marker (or model marker group) to convert.\n\t * @param {module:engine/view/elementdefinition~ElementDefinition|Function} config.view A view element definition or a function\n\t * that takes the model marker data as a parameter and returns a view UI element.\n\t * @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n\t * @returns {module:engine/conversion/downcasthelpers~DowncastHelpers}\n\t */\n\tmarkerToElement( config ) {\n\t\treturn this.add( downcastMarkerToElement( config ) );\n\t}\n\n\t/**\n\t * Model marker to highlight conversion helper.\n\t *\n\t * This conversion results in creating a highlight on view nodes. For this kind of conversion,\n\t * {@link module:engine/conversion/downcasthelpers~HighlightDescriptor} should be provided.\n\t *\n\t * For text nodes, a `` {@link module:engine/view/attributeelement~AttributeElement} is created and it wraps all text nodes\n\t * in the converted marker range. For example, a model marker set like this: `F[oo b]ar` becomes\n\t * `Far
` in the view.\n\t *\n\t * {@link module:engine/view/containerelement~ContainerElement} may provide a custom way of handling highlight. Most often,\n\t * the element itself is given classes and attributes described in the highlight descriptor (instead of being wrapped in ``).\n\t * For example, a model marker set like this: `[]` becomes ``\n\t * in the view.\n\t *\n\t * For container elements, the conversion is two-step. While the converter processes the highlight descriptor and passes it\n\t * to a container element, it is the container element instance itself that applies values from the highlight descriptor.\n\t * So, in a sense, the converter takes care of stating what should be applied on what, while the element decides how to apply that.\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).markerToHighlight( { model: 'comment', view: { classes: 'comment' } } );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).markerToHighlight( {\n\t *\t\t\tmodel: 'comment',\n\t *\t\t\tview: { classes: 'new-comment' },\n\t *\t\t\tconverterPriority: 'high'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'downcast' ).markerToHighlight( {\n\t *\t\t\tmodel: 'comment',\n\t *\t\t\tview: data => {\n\t *\t\t\t\t// Assuming that the marker name is in a form of comment:commentType.\n\t *\t\t\t\tconst commentType = data.markerName.split( ':' )[ 1 ];\n\t *\n\t *\t\t\t\treturn {\n\t *\t\t\t\t\tclasses: [ 'comment', 'comment-' + commentType ]\n\t *\t\t\t\t};\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t * If a function is passed as the `config.view` parameter, it will be used to generate the highlight descriptor. The function\n\t * receives the `data` object as a parameter and should return a\n\t * {@link module:engine/conversion/downcasthelpers~HighlightDescriptor highlight descriptor}.\n\t * The `data` object properties are passed from {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:addMarker}.\n\t *\n\t * See {@link module:engine/conversion/conversion~Conversion#for `conversion.for()`} to learn how to add a converter\n\t * to the conversion process.\n\t *\n\t * @method #markerToHighlight\n\t * @param {Object} config Conversion configuration.\n\t * @param {String} config.model The name of the model marker (or model marker group) to convert.\n\t * @param {module:engine/conversion/downcasthelpers~HighlightDescriptor|Function} config.view A highlight descriptor\n\t * that will be used for highlighting or a function that takes the model marker data as a parameter and returns a highlight descriptor.\n\t * @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n\t * @returns {module:engine/conversion/downcasthelpers~DowncastHelpers}\n\t */\n\tmarkerToHighlight( config ) {\n\t\treturn this.add( downcastMarkerToHighlight( config ) );\n\t}\n}\n\n/**\n * Function factory that creates a default downcast converter for text insertion changes.\n *\n * The converter automatically consumes the corresponding value from the consumables list and stops the event (see\n * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher}).\n *\n *\t\tmodelDispatcher.on( 'insert:$text', insertText() );\n *\n * @returns {Function} Insert text event converter.\n */\nexport function insertText() {\n\treturn ( evt, data, conversionApi ) => {\n\t\tif ( !conversionApi.consumable.consume( data.item, 'insert' ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst viewWriter = conversionApi.writer;\n\t\tconst viewPosition = conversionApi.mapper.toViewPosition( data.range.start );\n\t\tconst viewText = viewWriter.createText( data.item.data );\n\n\t\tviewWriter.insert( viewPosition, viewText );\n\t};\n}\n\n/**\n * Function factory that creates a default downcast converter for node remove changes.\n *\n *\t\tmodelDispatcher.on( 'remove', remove() );\n *\n * @returns {Function} Remove event converter.\n */\nexport function remove() {\n\treturn ( evt, data, conversionApi ) => {\n\t\t// Find view range start position by mapping model position at which the remove happened.\n\t\tconst viewStart = conversionApi.mapper.toViewPosition( data.position );\n\n\t\tconst modelEnd = data.position.getShiftedBy( data.length );\n\t\tconst viewEnd = conversionApi.mapper.toViewPosition( modelEnd, { isPhantom: true } );\n\n\t\tconst viewRange = conversionApi.writer.createRange( viewStart, viewEnd );\n\n\t\t// Trim the range to remove in case some UI elements are on the view range boundaries.\n\t\tconst removed = conversionApi.writer.remove( viewRange.getTrimmed() );\n\n\t\t// After the range is removed, unbind all view elements from the model.\n\t\t// Range inside view document fragment is used to unbind deeply.\n\t\tfor ( const child of conversionApi.writer.createRangeIn( removed ).getItems() ) {\n\t\t\tconversionApi.mapper.unbindViewElement( child );\n\t\t}\n\t};\n}\n\n/**\n * Creates a `` {@link module:engine/view/attributeelement~AttributeElement view attribute element} from the information\n * provided by the {@link module:engine/conversion/downcasthelpers~HighlightDescriptor highlight descriptor} object. If a priority\n * is not provided in the descriptor, the default priority will be used.\n *\n * @param {module:engine/conversion/downcasthelpers~HighlightDescriptor} descriptor\n * @returns {module:engine/view/attributeelement~AttributeElement}\n */\nexport function createViewElementFromHighlightDescriptor( descriptor ) {\n\tconst viewElement = new ViewAttributeElement( 'span', descriptor.attributes );\n\n\tif ( descriptor.classes ) {\n\t\tviewElement._addClass( descriptor.classes );\n\t}\n\n\tif ( descriptor.priority ) {\n\t\tviewElement._priority = descriptor.priority;\n\t}\n\n\tviewElement._id = descriptor.id;\n\n\treturn viewElement;\n}\n\n/**\n * Function factory that creates a converter which converts a non-collapsed {@link module:engine/model/selection~Selection model selection}\n * to a {@link module:engine/view/documentselection~DocumentSelection view selection}. The converter consumes appropriate\n * value from the `consumable` object and maps model positions from the selection to view positions.\n *\n *\t\tmodelDispatcher.on( 'selection', convertRangeSelection() );\n *\n * @returns {Function} Selection converter.\n */\nexport function convertRangeSelection() {\n\treturn ( evt, data, conversionApi ) => {\n\t\tconst selection = data.selection;\n\n\t\tif ( selection.isCollapsed ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( !conversionApi.consumable.consume( selection, 'selection' ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst viewRanges = [];\n\n\t\tfor ( const range of selection.getRanges() ) {\n\t\t\tconst viewRange = conversionApi.mapper.toViewRange( range );\n\t\t\tviewRanges.push( viewRange );\n\t\t}\n\n\t\tconversionApi.writer.setSelection( viewRanges, { backward: selection.isBackward } );\n\t};\n}\n\n/**\n * Function factory that creates a converter which converts a collapsed {@link module:engine/model/selection~Selection model selection} to\n * a {@link module:engine/view/documentselection~DocumentSelection view selection}. The converter consumes appropriate\n * value from the `consumable` object, maps the model selection position to the view position and breaks\n * {@link module:engine/view/attributeelement~AttributeElement attribute elements} at the selection position.\n *\n *\t\tmodelDispatcher.on( 'selection', convertCollapsedSelection() );\n *\n * An example of the view state before and after converting the collapsed selection:\n *\n *\t\t f^oobar
\n *\t\t-> f^oobar
\n *\n * By breaking attribute elements like ``, the selection is in a correct element. Then, when the selection attribute is\n * converted, broken attributes might be merged again, or the position where the selection is may be wrapped\n * with different, appropriate attribute elements.\n *\n * See also {@link module:engine/conversion/downcasthelpers~clearAttributes} which does a clean-up\n * by merging attributes.\n *\n * @returns {Function} Selection converter.\n */\nexport function convertCollapsedSelection() {\n\treturn ( evt, data, conversionApi ) => {\n\t\tconst selection = data.selection;\n\n\t\tif ( !selection.isCollapsed ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( !conversionApi.consumable.consume( selection, 'selection' ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst viewWriter = conversionApi.writer;\n\t\tconst modelPosition = selection.getFirstPosition();\n\t\tconst viewPosition = conversionApi.mapper.toViewPosition( modelPosition );\n\t\tconst brokenPosition = viewWriter.breakAttributes( viewPosition );\n\n\t\tviewWriter.setSelection( brokenPosition );\n\t};\n}\n\n/**\n * Function factory that creates a converter which clears artifacts after the previous\n * {@link module:engine/model/selection~Selection model selection} conversion. It removes all empty\n * {@link module:engine/view/attributeelement~AttributeElement view attribute elements} and merges sibling attributes at all start and end\n * positions of all ranges.\n *\n *\t\t ^
\n *\t\t-> ^
\n *\n *\t\t foo^barbar
\n *\t\t-> foo^barbar
\n *\n *\t\t foo^barbar
\n *\t\t-> foo^barbar
\n *\n * This listener should be assigned before any converter for the new selection:\n *\n *\t\tmodelDispatcher.on( 'selection', clearAttributes() );\n *\n * See {@link module:engine/conversion/downcasthelpers~convertCollapsedSelection}\n * which does the opposite by breaking attributes in the selection position.\n *\n * @returns {Function} Selection converter.\n */\nexport function clearAttributes() {\n\treturn ( evt, data, conversionApi ) => {\n\t\tconst viewWriter = conversionApi.writer;\n\t\tconst viewSelection = viewWriter.document.selection;\n\n\t\tfor ( const range of viewSelection.getRanges() ) {\n\t\t\t// Not collapsed selection should not have artifacts.\n\t\t\tif ( range.isCollapsed ) {\n\t\t\t\t// Position might be in the node removed by the view writer.\n\t\t\t\tif ( range.end.parent.document ) {\n\t\t\t\t\tconversionApi.writer.mergeAttributes( range.start );\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\t\tviewWriter.setSelection( null );\n\t};\n}\n\n/**\n * Function factory that creates a converter which converts set/change/remove attribute changes from the model to the view.\n * It can also be used to convert selection attributes. In that case, an empty attribute element will be created and the\n * selection will be put inside it.\n *\n * Attributes from the model are converted to a view element that will be wrapping these view nodes that are bound to\n * model elements having the given attribute. This is useful for attributes like `bold` that may be set on text nodes in the model\n * but are represented as an element in the view:\n *\n *\t\t[paragraph] MODEL ====> VIEW \n *\t\t\t|- a {bold: true} |- \n *\t\t\t|- b {bold: true} | |- ab\n *\t\t\t|- c |- c\n *\n * Passed `Function` will be provided with the attribute value and then all the parameters of the\n * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:attribute `attribute` event}.\n * It is expected that the function returns an {@link module:engine/view/element~Element}.\n * The result of the function will be the wrapping element.\n * When the provided `Function` does not return any element, no conversion will take place.\n *\n * The converter automatically consumes the corresponding value from the consumables list and stops the event (see\n * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher}).\n *\n *\t\tmodelDispatcher.on( 'attribute:bold', wrap( ( modelAttributeValue, viewWriter ) => {\n *\t\t\treturn viewWriter.createAttributeElement( 'strong' );\n *\t\t} );\n *\n * @protected\n * @param {Function} elementCreator Function returning a view element that will be used for wrapping.\n * @returns {Function} Set/change attribute converter.\n */\nexport function wrap( elementCreator ) {\n\treturn ( evt, data, conversionApi ) => {\n\t\t// Recreate current wrapping node. It will be used to unwrap view range if the attribute value has changed\n\t\t// or the attribute was removed.\n\t\tconst oldViewElement = elementCreator( data.attributeOldValue, conversionApi.writer );\n\n\t\t// Create node to wrap with.\n\t\tconst newViewElement = elementCreator( data.attributeNewValue, conversionApi.writer );\n\n\t\tif ( !oldViewElement && !newViewElement ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( !conversionApi.consumable.consume( data.item, evt.name ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst viewWriter = conversionApi.writer;\n\t\tconst viewSelection = viewWriter.document.selection;\n\n\t\tif ( data.item instanceof ModelSelection || data.item instanceof DocumentSelection ) {\n\t\t\t// Selection attribute conversion.\n\t\t\tviewWriter.wrap( viewSelection.getFirstRange(), newViewElement );\n\t\t} else {\n\t\t\t// Node attribute conversion.\n\t\t\tlet viewRange = conversionApi.mapper.toViewRange( data.range );\n\n\t\t\t// First, unwrap the range from current wrapper.\n\t\t\tif ( data.attributeOldValue !== null && oldViewElement ) {\n\t\t\t\tviewRange = viewWriter.unwrap( viewRange, oldViewElement );\n\t\t\t}\n\n\t\t\tif ( data.attributeNewValue !== null && newViewElement ) {\n\t\t\t\tviewWriter.wrap( viewRange, newViewElement );\n\t\t\t}\n\t\t}\n\t};\n}\n\n/**\n * Function factory that creates a converter which converts node insertion changes from the model to the view.\n * The function passed will be provided with all the parameters of the dispatcher's\n * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher#event:insert `insert` event}.\n * It is expected that the function returns an {@link module:engine/view/element~Element}.\n * The result of the function will be inserted into the view.\n *\n * The converter automatically consumes the corresponding value from the consumables list, stops the event (see\n * {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher}) and binds the model and view elements.\n *\n *\t\tdowncastDispatcher.on(\n *\t\t\t'insert:myElem',\n *\t\t\tinsertElement( ( modelItem, viewWriter ) => {\n *\t\t\t\tconst text = viewWriter.createText( 'myText' );\n *\t\t\t\tconst myElem = viewWriter.createElement( 'myElem', { myAttr: 'my-' + modelItem.getAttribute( 'myAttr' ) }, text );\n *\n *\t\t\t\t// Do something fancy with `myElem` using `modelItem` or other parameters.\n *\n *\t\t\t\treturn myElem;\n *\t\t\t}\n *\t\t) );\n *\n * @protected\n * @param {Function} elementCreator Function returning a view element, which will be inserted.\n * @returns {Function} Insert element event converter.\n */\nexport function insertElement( elementCreator ) {\n\treturn ( evt, data, conversionApi ) => {\n\t\tconst viewElement = elementCreator( data.item, conversionApi.writer );\n\n\t\tif ( !viewElement ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( !conversionApi.consumable.consume( data.item, 'insert' ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst viewPosition = conversionApi.mapper.toViewPosition( data.range.start );\n\n\t\tconversionApi.mapper.bindElements( data.item, viewElement );\n\t\tconversionApi.writer.insert( viewPosition, viewElement );\n\t};\n}\n\n/**\n * Function factory that creates a converter which converts marker adding change to the\n * {@link module:engine/view/uielement~UIElement view UI element}.\n *\n * The view UI element that will be added to the view depends on the passed parameter. See {@link ~insertElement}.\n * In case of a non-collapsed range, the UI element will not wrap nodes but separate elements will be placed at the beginning\n * and at the end of the range.\n *\n * This converter binds created UI elements with the marker name using {@link module:engine/conversion/mapper~Mapper#bindElementToMarker}.\n *\n * @protected\n * @param {module:engine/view/uielement~UIElement|Function} elementCreator A view UI element or a function returning the view element\n * that will be inserted.\n * @returns {Function} Insert element event converter.\n */\nexport function insertUIElement( elementCreator ) {\n\treturn ( evt, data, conversionApi ) => {\n\t\t// Create two view elements. One will be inserted at the beginning of marker, one at the end.\n\t\t// If marker is collapsed, only \"opening\" element will be inserted.\n\t\tdata.isOpening = true;\n\t\tconst viewStartElement = elementCreator( data, conversionApi.writer );\n\n\t\tdata.isOpening = false;\n\t\tconst viewEndElement = elementCreator( data, conversionApi.writer );\n\n\t\tif ( !viewStartElement || !viewEndElement ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst markerRange = data.markerRange;\n\n\t\t// Marker that is collapsed has consumable build differently that non-collapsed one.\n\t\t// For more information see `addMarker` event description.\n\t\t// If marker's range is collapsed - check if it can be consumed.\n\t\tif ( markerRange.isCollapsed && !conversionApi.consumable.consume( markerRange, evt.name ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\t// If marker's range is not collapsed - consume all items inside.\n\t\tfor ( const value of markerRange ) {\n\t\t\tif ( !conversionApi.consumable.consume( value.item, evt.name ) ) {\n\t\t\t\treturn;\n\t\t\t}\n\t\t}\n\n\t\tconst mapper = conversionApi.mapper;\n\t\tconst viewWriter = conversionApi.writer;\n\n\t\t// Add \"opening\" element.\n\t\tviewWriter.insert( mapper.toViewPosition( markerRange.start ), viewStartElement );\n\t\tconversionApi.mapper.bindElementToMarker( viewStartElement, data.markerName );\n\n\t\t// Add \"closing\" element only if range is not collapsed.\n\t\tif ( !markerRange.isCollapsed ) {\n\t\t\tviewWriter.insert( mapper.toViewPosition( markerRange.end ), viewEndElement );\n\t\t\tconversionApi.mapper.bindElementToMarker( viewEndElement, data.markerName );\n\t\t}\n\n\t\tevt.stop();\n\t};\n}\n\n// Function factory that returns a default downcast converter for removing a {@link module:engine/view/uielement~UIElement UI element}\n// basing on marker remove change.\n//\n// This converter unbinds elements from the marker name.\n//\n// @returns {Function} Removed UI element converter.\nfunction removeUIElement() {\n\treturn ( evt, data, conversionApi ) => {\n\t\tconst elements = conversionApi.mapper.markerNameToElements( data.markerName );\n\n\t\tif ( !elements ) {\n\t\t\treturn;\n\t\t}\n\n\t\tfor ( const element of elements ) {\n\t\t\tconversionApi.mapper.unbindElementFromMarkerName( element, data.markerName );\n\t\t\tconversionApi.writer.clear( conversionApi.writer.createRangeOn( element ), element );\n\t\t}\n\n\t\tconversionApi.writer.clearClonedElementsGroup( data.markerName );\n\n\t\tevt.stop();\n\t};\n}\n\n// Function factory that creates a converter which converts set/change/remove attribute changes from the model to the view.\n//\n// Attributes from the model are converted to the view element attributes in the view. You may provide a custom function to generate\n// a key-value attribute pair to add/change/remove. If not provided, model attributes will be converted to view element\n// attributes on a one-to-one basis.\n//\n// *Note:** The provided attribute creator should always return the same `key` for a given attribute from the model.\n//\n// The converter automatically consumes the corresponding value from the consumables list and stops the event (see\n// {@link module:engine/conversion/downcastdispatcher~DowncastDispatcher}).\n//\n//\t\tmodelDispatcher.on( 'attribute:customAttr:myElem', changeAttribute( ( value, data ) => {\n//\t\t\t// Change attribute key from `customAttr` to `class` in the view.\n//\t\t\tconst key = 'class';\n//\t\t\tlet value = data.attributeNewValue;\n//\n//\t\t\t// Force attribute value to 'empty' if the model element is empty.\n//\t\t\tif ( data.item.childCount === 0 ) {\n//\t\t\t\tvalue = 'empty';\n//\t\t\t}\n//\n//\t\t\t// Return the key-value pair.\n//\t\t\treturn { key, value };\n//\t\t} ) );\n//\n// @param {Function} [attributeCreator] Function returning an object with two properties: `key` and `value`, which\n// represent the attribute key and attribute value to be set on a {@link module:engine/view/element~Element view element}.\n// The function is passed the model attribute value as the first parameter and additional data about the change as the second parameter.\n// @returns {Function} Set/change attribute converter.\nfunction changeAttribute( attributeCreator ) {\n\treturn ( evt, data, conversionApi ) => {\n\t\tconst oldAttribute = attributeCreator( data.attributeOldValue, data );\n\t\tconst newAttribute = attributeCreator( data.attributeNewValue, data );\n\n\t\tif ( !oldAttribute && !newAttribute ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( !conversionApi.consumable.consume( data.item, evt.name ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst viewElement = conversionApi.mapper.toViewElement( data.item );\n\t\tconst viewWriter = conversionApi.writer;\n\n\t\t// If model item cannot be mapped to a view element, it means item is not an `Element` instance but a `TextProxy` node.\n\t\t// Only elements can have attributes in a view so do not proceed for anything else (#1587).\n\t\tif ( !viewElement ) {\n\t\t\t/**\n\t\t\t * This error occurs when a {@link module:engine/model/textproxy~TextProxy text node's} attribute is to be downcasted\n\t\t\t * by {@link module:engine/conversion/conversion~Conversion#attributeToAttribute `Attribute to Attribute converter`}.\n\t\t\t * In most cases it is caused by converters misconfiguration when only \"generic\" converter is defined:\n\t\t\t *\n\t\t\t *\t\teditor.conversion.for( 'downcast' ).attributeToAttribute( {\n\t\t\t *\t\t\tmodel: 'attribute-name',\n\t\t\t *\t\t\tview: 'attribute-name'\n\t\t\t *\t\t} ) );\n\t\t\t *\n\t\t\t * and given attribute is used on text node, for example:\n\t\t\t *\n\t\t\t *\t\tmodel.change( writer => {\n\t\t\t *\t\t\twriter.insertText( 'Foo', { 'attribute-name': 'bar' }, parent, 0 );\n\t\t\t *\t\t} );\n\t\t\t *\n\t\t\t * In such cases, to convert the same attribute for both {@link module:engine/model/element~Element}\n\t\t\t * and {@link module:engine/model/textproxy~TextProxy `Text`} nodes, text specific\n\t\t\t * {@link module:engine/conversion/conversion~Conversion#attributeToElement `Attribute to Element converter`}\n\t\t\t * with higher {@link module:utils/priorities~PriorityString priority} must also be defined:\n\t\t\t *\n\t\t\t *\t\teditor.conversion.for( 'downcast' ).attributeToElement( {\n\t\t\t *\t\t\tmodel: {\n\t\t\t *\t\t\t\tkey: 'attribute-name',\n\t\t\t *\t\t\t\tname: '$text'\n\t\t\t *\t\t\t},\n\t\t\t *\t\t\tview: ( value, writer ) => {\n\t\t\t *\t\t\t\treturn writer.createAttributeElement( 'span', { 'attribute-name': value } );\n\t\t\t *\t\t\t},\n\t\t\t *\t\t\tconverterPriority: 'high'\n\t\t\t *\t\t} ) );\n\t\t\t *\n\t\t\t * @error conversion-attribute-to-attribute-on-text\n\t\t\t */\n\t\t\tthrow new CKEditorError(\n\t\t\t\t'conversion-attribute-to-attribute-on-text: ' +\n\t\t\t\t'Trying to convert text node\\'s attribute with attribute-to-attribute converter.',\n\t\t\t\t[ data, conversionApi ]\n\t\t\t);\n\t\t}\n\n\t\t// First remove the old attribute if there was one.\n\t\tif ( data.attributeOldValue !== null && oldAttribute ) {\n\t\t\tif ( oldAttribute.key == 'class' ) {\n\t\t\t\tconst classes = Array.isArray( oldAttribute.value ) ? oldAttribute.value : [ oldAttribute.value ];\n\n\t\t\t\tfor ( const className of classes ) {\n\t\t\t\t\tviewWriter.removeClass( className, viewElement );\n\t\t\t\t}\n\t\t\t} else if ( oldAttribute.key == 'style' ) {\n\t\t\t\tconst keys = Object.keys( oldAttribute.value );\n\n\t\t\t\tfor ( const key of keys ) {\n\t\t\t\t\tviewWriter.removeStyle( key, viewElement );\n\t\t\t\t}\n\t\t\t} else {\n\t\t\t\tviewWriter.removeAttribute( oldAttribute.key, viewElement );\n\t\t\t}\n\t\t}\n\n\t\t// Then set the new attribute.\n\t\tif ( data.attributeNewValue !== null && newAttribute ) {\n\t\t\tif ( newAttribute.key == 'class' ) {\n\t\t\t\tconst classes = Array.isArray( newAttribute.value ) ? newAttribute.value : [ newAttribute.value ];\n\n\t\t\t\tfor ( const className of classes ) {\n\t\t\t\t\tviewWriter.addClass( className, viewElement );\n\t\t\t\t}\n\t\t\t} else if ( newAttribute.key == 'style' ) {\n\t\t\t\tconst keys = Object.keys( newAttribute.value );\n\n\t\t\t\tfor ( const key of keys ) {\n\t\t\t\t\tviewWriter.setStyle( key, newAttribute.value[ key ], viewElement );\n\t\t\t\t}\n\t\t\t} else {\n\t\t\t\tviewWriter.setAttribute( newAttribute.key, newAttribute.value, viewElement );\n\t\t\t}\n\t\t}\n\t};\n}\n\n// Function factory that creates a converter which converts the text inside marker's range. The converter wraps the text with\n// {@link module:engine/view/attributeelement~AttributeElement} created from the provided descriptor.\n// See {link module:engine/conversion/downcasthelpers~createViewElementFromHighlightDescriptor}.\n//\n// It can also be used to convert the selection that is inside a marker. In that case, an empty attribute element will be\n// created and the selection will be put inside it.\n//\n// If the highlight descriptor does not provide the `priority` property, `10` will be used.\n//\n// If the highlight descriptor does not provide the `id` property, the name of the marker will be used.\n//\n// This converter binds the created {@link module:engine/view/attributeelement~AttributeElement attribute elemens} with the marker name\n// using the {@link module:engine/conversion/mapper~Mapper#bindElementToMarker} method.\n//\n// @param {module:engine/conversion/downcasthelpers~HighlightDescriptor|Function} highlightDescriptor\n// @returns {Function}\nfunction highlightText( highlightDescriptor ) {\n\treturn ( evt, data, conversionApi ) => {\n\t\tif ( !data.item ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( !( data.item instanceof ModelSelection || data.item instanceof DocumentSelection ) && !data.item.is( 'textProxy' ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst descriptor = prepareDescriptor( highlightDescriptor, data, conversionApi );\n\n\t\tif ( !descriptor ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( !conversionApi.consumable.consume( data.item, evt.name ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst viewElement = createViewElementFromHighlightDescriptor( descriptor );\n\t\tconst viewWriter = conversionApi.writer;\n\t\tconst viewSelection = viewWriter.document.selection;\n\n\t\tif ( data.item instanceof ModelSelection || data.item instanceof DocumentSelection ) {\n\t\t\tviewWriter.wrap( viewSelection.getFirstRange(), viewElement, viewSelection );\n\t\t} else {\n\t\t\tconst viewRange = conversionApi.mapper.toViewRange( data.range );\n\t\t\tconst rangeAfterWrap = viewWriter.wrap( viewRange, viewElement );\n\n\t\t\tfor ( const element of rangeAfterWrap.getItems() ) {\n\t\t\t\tif ( element.is( 'attributeElement' ) && element.isSimilar( viewElement ) ) {\n\t\t\t\t\tconversionApi.mapper.bindElementToMarker( element, data.markerName );\n\n\t\t\t\t\t// One attribute element is enough, because all of them are bound together by the view writer.\n\t\t\t\t\t// Mapper uses this binding to get all the elements no matter how many of them are registered in the mapper.\n\t\t\t\t\tbreak;\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\t};\n}\n\n// Converter function factory. It creates a function which applies the marker's highlight to an element inside the marker's range.\n//\n// The converter checks if an element has the `addHighlight` function stored as a\n// {@link module:engine/view/element~Element#_setCustomProperty custom property} and, if so, uses it to apply the highlight.\n// In such case the converter will consume all element's children, assuming that they were handled by the element itself.\n//\n// When the `addHighlight` custom property is not present, the element is not converted in any special way.\n// This means that converters will proceed to convert the element's child nodes.\n//\n// If the highlight descriptor does not provide the `priority` property, `10` will be used.\n//\n// If the highlight descriptor does not provide the `id` property, the name of the marker will be used.\n//\n// This converter binds altered {@link module:engine/view/containerelement~ContainerElement container elements} with the marker name using\n// the {@link module:engine/conversion/mapper~Mapper#bindElementToMarker} method.\n//\n// @param {module:engine/conversion/downcasthelpers~HighlightDescriptor|Function} highlightDescriptor\n// @returns {Function}\nfunction highlightElement( highlightDescriptor ) {\n\treturn ( evt, data, conversionApi ) => {\n\t\tif ( !data.item ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( !( data.item instanceof ModelElement ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst descriptor = prepareDescriptor( highlightDescriptor, data, conversionApi );\n\n\t\tif ( !descriptor ) {\n\t\t\treturn;\n\t\t}\n\n\t\tif ( !conversionApi.consumable.test( data.item, evt.name ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst viewElement = conversionApi.mapper.toViewElement( data.item );\n\n\t\tif ( viewElement && viewElement.getCustomProperty( 'addHighlight' ) ) {\n\t\t\t// Consume element itself.\n\t\t\tconversionApi.consumable.consume( data.item, evt.name );\n\n\t\t\t// Consume all children nodes.\n\t\t\tfor ( const value of ModelRange._createIn( data.item ) ) {\n\t\t\t\tconversionApi.consumable.consume( value.item, evt.name );\n\t\t\t}\n\n\t\t\tviewElement.getCustomProperty( 'addHighlight' )( viewElement, descriptor, conversionApi.writer );\n\n\t\t\tconversionApi.mapper.bindElementToMarker( viewElement, data.markerName );\n\t\t}\n\t};\n}\n\n// Function factory that creates a converter which converts the removing model marker to the view.\n//\n// Both text nodes and elements are handled by this converter but they are handled a bit differently.\n//\n// Text nodes are unwrapped using the {@link module:engine/view/attributeelement~AttributeElement attribute element} created from the\n// provided highlight descriptor. See {link module:engine/conversion/downcasthelpers~HighlightDescriptor}.\n//\n// For elements, the converter checks if an element has the `removeHighlight` function stored as a\n// {@link module:engine/view/element~Element#_setCustomProperty custom property}. If so, it uses it to remove the highlight.\n// In such case, the children of that element will not be converted.\n//\n// When `removeHighlight` is not present, the element is not converted in any special way.\n// The converter will proceed to convert the element's child nodes instead.\n//\n// If the highlight descriptor does not provide the `priority` property, `10` will be used.\n//\n// If the highlight descriptor does not provide the `id` property, the name of the marker will be used.\n//\n// This converter unbinds elements from the marker name.\n//\n// @param {module:engine/conversion/downcasthelpers~HighlightDescriptor|Function} highlightDescriptor\n// @returns {Function}\nfunction removeHighlight( highlightDescriptor ) {\n\treturn ( evt, data, conversionApi ) => {\n\t\t// This conversion makes sense only for non-collapsed range.\n\t\tif ( data.markerRange.isCollapsed ) {\n\t\t\treturn;\n\t\t}\n\n\t\tconst descriptor = prepareDescriptor( highlightDescriptor, data, conversionApi );\n\n\t\tif ( !descriptor ) {\n\t\t\treturn;\n\t\t}\n\n\t\t// View element that will be used to unwrap `AttributeElement`s.\n\t\tconst viewHighlightElement = createViewElementFromHighlightDescriptor( descriptor );\n\n\t\t// Get all elements bound with given marker name.\n\t\tconst elements = conversionApi.mapper.markerNameToElements( data.markerName );\n\n\t\tif ( !elements ) {\n\t\t\treturn;\n\t\t}\n\n\t\tfor ( const element of elements ) {\n\t\t\tconversionApi.mapper.unbindElementFromMarkerName( element, data.markerName );\n\n\t\t\tif ( element.is( 'attributeElement' ) ) {\n\t\t\t\tconversionApi.writer.unwrap( conversionApi.writer.createRangeOn( element ), viewHighlightElement );\n\t\t\t} else {\n\t\t\t\t// if element.is( 'containerElement' ).\n\t\t\t\telement.getCustomProperty( 'removeHighlight' )( element, descriptor.id, conversionApi.writer );\n\t\t\t}\n\t\t}\n\n\t\tconversionApi.writer.clearClonedElementsGroup( data.markerName );\n\n\t\tevt.stop();\n\t};\n}\n\n// Model element to view element conversion helper.\n//\n// See {@link ~DowncastHelpers#elementToElement `.elementToElement()` downcast helper} for examples.\n//\n// @param {Object} config Conversion configuration.\n// @param {String} config.model The name of the model element to convert.\n// @param {module:engine/view/elementdefinition~ElementDefinition|Function} config.view A view element definition or a function\n// that takes the model element and {@link module:engine/view/downcastwriter~DowncastWriter view downcast writer}\n// as parameters and returns a view container element.\n// @returns {Function} Conversion helper.\nfunction downcastElementToElement( config ) {\n\tconfig = cloneDeep( config );\n\n\tconfig.view = normalizeToElementConfig( config.view, 'container' );\n\n\treturn dispatcher => {\n\t\tdispatcher.on( 'insert:' + config.model, insertElement( config.view ), { priority: config.converterPriority || 'normal' } );\n\t};\n}\n\n// Model attribute to view element conversion helper.\n//\n// See {@link ~DowncastHelpers#attributeToElement `.attributeToElement()` downcast helper} for examples.\n//\n// @param {Object} config Conversion configuration.\n// @param {String|Object} config.model The key of the attribute to convert from or a `{ key, values }` object. `values` is an array\n// of `String`s with possible values if the model attribute is an enumerable.\n// @param {module:engine/view/elementdefinition~ElementDefinition|Function|Object} config.view A view element definition or a function\n// that takes the model attribute value and {@link module:engine/view/downcastwriter~DowncastWriter view downcast writer}\n// as parameters and returns a view attribute element. If `config.model.values` is\n// given, `config.view` should be an object assigning values from `config.model.values` to view element definitions or functions.\n// @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n// @returns {Function} Conversion helper.\nfunction downcastAttributeToElement( config ) {\n\tconfig = cloneDeep( config );\n\n\tconst modelKey = config.model.key ? config.model.key : config.model;\n\tlet eventName = 'attribute:' + modelKey;\n\n\tif ( config.model.name ) {\n\t\teventName += ':' + config.model.name;\n\t}\n\n\tif ( config.model.values ) {\n\t\tfor ( const modelValue of config.model.values ) {\n\t\t\tconfig.view[ modelValue ] = normalizeToElementConfig( config.view[ modelValue ], 'attribute' );\n\t\t}\n\t} else {\n\t\tconfig.view = normalizeToElementConfig( config.view, 'attribute' );\n\t}\n\n\tconst elementCreator = getFromAttributeCreator( config );\n\n\treturn dispatcher => {\n\t\tdispatcher.on( eventName, wrap( elementCreator ), { priority: config.converterPriority || 'normal' } );\n\t};\n}\n\n// Model attribute to view attribute conversion helper.\n//\n// See {@link ~DowncastHelpers#attributeToAttribute `.attributeToAttribute()` downcast helper} for examples.\n//\n// @param {Object} config Conversion configuration.\n// @param {String|Object} config.model The key of the attribute to convert from or a `{ key, values, [ name ] }` object describing\n// the attribute key, possible values and, optionally, an element name to convert from.\n// @param {String|Object|Function} config.view A view attribute key, or a `{ key, value }` object or a function that takes\n// the model attribute value and returns a `{ key, value }` object. If `key` is `'class'`, `value` can be a `String` or an\n// array of `String`s. If `key` is `'style'`, `value` is an object with key-value pairs. In other cases, `value` is a `String`.\n// If `config.model.values` is set, `config.view` should be an object assigning values from `config.model.values` to\n// `{ key, value }` objects or a functions.\n// @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n// @returns {Function} Conversion helper.\nfunction downcastAttributeToAttribute( config ) {\n\tconfig = cloneDeep( config );\n\n\tconst modelKey = config.model.key ? config.model.key : config.model;\n\tlet eventName = 'attribute:' + modelKey;\n\n\tif ( config.model.name ) {\n\t\teventName += ':' + config.model.name;\n\t}\n\n\tif ( config.model.values ) {\n\t\tfor ( const modelValue of config.model.values ) {\n\t\t\tconfig.view[ modelValue ] = normalizeToAttributeConfig( config.view[ modelValue ] );\n\t\t}\n\t} else {\n\t\tconfig.view = normalizeToAttributeConfig( config.view );\n\t}\n\n\tconst elementCreator = getFromAttributeCreator( config );\n\n\treturn dispatcher => {\n\t\tdispatcher.on( eventName, changeAttribute( elementCreator ), { priority: config.converterPriority || 'normal' } );\n\t};\n}\n\n// Model marker to view element conversion helper.\n//\n// See {@link ~DowncastHelpers#markerToElement `.markerToElement()` downcast helper} for examples.\n//\n// @param {Object} config Conversion configuration.\n// @param {String} config.model The name of the model marker (or model marker group) to convert.\n// @param {module:engine/view/elementdefinition~ElementDefinition|Function} config.view A view element definition or a function\n// that takes the model marker data as a parameter and returns a view UI element.\n// @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n// @returns {Function} Conversion helper.\nfunction downcastMarkerToElement( config ) {\n\tconfig = cloneDeep( config );\n\n\tconfig.view = normalizeToElementConfig( config.view, 'ui' );\n\n\treturn dispatcher => {\n\t\tdispatcher.on( 'addMarker:' + config.model, insertUIElement( config.view ), { priority: config.converterPriority || 'normal' } );\n\t\tdispatcher.on( 'removeMarker:' + config.model, removeUIElement( config.view ), { priority: config.converterPriority || 'normal' } );\n\t};\n}\n\n// Model marker to highlight conversion helper.\n//\n// See {@link ~DowncastHelpers#markerToElement `.markerToElement()` downcast helper} for examples.\n//\n// @param {Object} config Conversion configuration.\n// @param {String} config.model The name of the model marker (or model marker group) to convert.\n// @param {module:engine/conversion/downcasthelpers~HighlightDescriptor|Function} config.view A highlight descriptor\n// that will be used for highlighting or a function that takes the model marker data as a parameter and returns a highlight descriptor.\n// @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n// @returns {Function} Conversion helper.\nfunction downcastMarkerToHighlight( config ) {\n\treturn dispatcher => {\n\t\tdispatcher.on( 'addMarker:' + config.model, highlightText( config.view ), { priority: config.converterPriority || 'normal' } );\n\t\tdispatcher.on( 'addMarker:' + config.model, highlightElement( config.view ), { priority: config.converterPriority || 'normal' } );\n\t\tdispatcher.on( 'removeMarker:' + config.model, removeHighlight( config.view ), { priority: config.converterPriority || 'normal' } );\n\t};\n}\n\n// Takes `config.view`, and if it is an {@link module:engine/view/elementdefinition~ElementDefinition}, converts it\n// to a function (because lower level converters accept only element creator functions).\n//\n// @param {module:engine/view/elementdefinition~ElementDefinition|Function} view View configuration.\n// @param {'container'|'attribute'|'ui'} viewElementType View element type to create.\n// @returns {Function} Element creator function to use in lower level converters.\nfunction normalizeToElementConfig( view, viewElementType ) {\n\tif ( typeof view == 'function' ) {\n\t\t// If `view` is already a function, don't do anything.\n\t\treturn view;\n\t}\n\n\treturn ( modelData, viewWriter ) => createViewElementFromDefinition( view, viewWriter, viewElementType );\n}\n\n// Creates a view element instance from the provided {@link module:engine/view/elementdefinition~ElementDefinition} and class.\n//\n// @param {module:engine/view/elementdefinition~ElementDefinition} viewElementDefinition\n// @param {module:engine/view/downcastwriter~DowncastWriter} viewWriter\n// @param {'container'|'attribute'|'ui'} viewElementType\n// @returns {module:engine/view/element~Element}\nfunction createViewElementFromDefinition( viewElementDefinition, viewWriter, viewElementType ) {\n\tif ( typeof viewElementDefinition == 'string' ) {\n\t\t// If `viewElementDefinition` is given as a `String`, normalize it to an object with `name` property.\n\t\tviewElementDefinition = { name: viewElementDefinition };\n\t}\n\n\tlet element;\n\tconst attributes = Object.assign( {}, viewElementDefinition.attributes );\n\n\tif ( viewElementType == 'container' ) {\n\t\telement = viewWriter.createContainerElement( viewElementDefinition.name, attributes );\n\t} else if ( viewElementType == 'attribute' ) {\n\t\tconst options = {\n\t\t\tpriority: viewElementDefinition.priority || ViewAttributeElement.DEFAULT_PRIORITY\n\t\t};\n\n\t\telement = viewWriter.createAttributeElement( viewElementDefinition.name, attributes, options );\n\t} else {\n\t\t// 'ui'.\n\t\telement = viewWriter.createUIElement( viewElementDefinition.name, attributes );\n\t}\n\n\tif ( viewElementDefinition.styles ) {\n\t\tconst keys = Object.keys( viewElementDefinition.styles );\n\n\t\tfor ( const key of keys ) {\n\t\t\tviewWriter.setStyle( key, viewElementDefinition.styles[ key ], element );\n\t\t}\n\t}\n\n\tif ( viewElementDefinition.classes ) {\n\t\tconst classes = viewElementDefinition.classes;\n\n\t\tif ( typeof classes == 'string' ) {\n\t\t\tviewWriter.addClass( classes, element );\n\t\t} else {\n\t\t\tfor ( const className of classes ) {\n\t\t\t\tviewWriter.addClass( className, element );\n\t\t\t}\n\t\t}\n\t}\n\n\treturn element;\n}\n\nfunction getFromAttributeCreator( config ) {\n\tif ( config.model.values ) {\n\t\treturn ( modelAttributeValue, viewWriter ) => {\n\t\t\tconst view = config.view[ modelAttributeValue ];\n\n\t\t\tif ( view ) {\n\t\t\t\treturn view( modelAttributeValue, viewWriter );\n\t\t\t}\n\n\t\t\treturn null;\n\t\t};\n\t} else {\n\t\treturn config.view;\n\t}\n}\n\n// Takes the configuration, adds default parameters if they do not exist and normalizes other parameters to be used in downcast converters\n// for generating a view attribute.\n//\n// @param {Object} view View configuration.\nfunction normalizeToAttributeConfig( view ) {\n\tif ( typeof view == 'string' ) {\n\t\treturn modelAttributeValue => ( { key: view, value: modelAttributeValue } );\n\t} else if ( typeof view == 'object' ) {\n\t\t// { key, value, ... }\n\t\tif ( view.value ) {\n\t\t\treturn () => view;\n\t\t}\n\t\t// { key, ... }\n\t\telse {\n\t\t\treturn modelAttributeValue => ( { key: view.key, value: modelAttributeValue } );\n\t\t}\n\t} else {\n\t\t// function.\n\t\treturn view;\n\t}\n}\n\n// Helper function for `highlight`. Prepares the actual descriptor object using value passed to the converter.\nfunction prepareDescriptor( highlightDescriptor, data, conversionApi ) {\n\t// If passed descriptor is a creator function, call it. If not, just use passed value.\n\tconst descriptor = typeof highlightDescriptor == 'function' ?\n\t\thighlightDescriptor( data, conversionApi ) :\n\t\thighlightDescriptor;\n\n\tif ( !descriptor ) {\n\t\treturn null;\n\t}\n\n\t// Apply default descriptor priority.\n\tif ( !descriptor.priority ) {\n\t\tdescriptor.priority = 10;\n\t}\n\n\t// Default descriptor id is marker name.\n\tif ( !descriptor.id ) {\n\t\tdescriptor.id = data.markerName;\n\t}\n\n\treturn descriptor;\n}\n\n/**\n * An object describing how the marker highlight should be represented in the view.\n *\n * Each text node contained in a highlighted range will be wrapped in a ``\n * {@link module:engine/view/attributeelement~AttributeElement view attribute element} with CSS class(es), attributes and a priority\n * described by this object.\n *\n * Additionally, each {@link module:engine/view/containerelement~ContainerElement container element} can handle displaying the highlight\n * separately by providing the `addHighlight` and `removeHighlight` custom properties. In this case:\n *\n * * The `HighlightDescriptor` object is passed to the `addHighlight` function upon conversion and should be used to apply the highlight to\n * the element.\n * * The descriptor `id` is passed to the `removeHighlight` function upon conversion and should be used to remove the highlight with the\n * given ID from the element.\n *\n * @typedef {Object} module:engine/conversion/downcasthelpers~HighlightDescriptor\n *\n * @property {String|Array.} classes A CSS class or an array of classes to set. If the descriptor is used to\n * create an {@link module:engine/view/attributeelement~AttributeElement attribute element} over text nodes, these classes will be set\n * on that attribute element. If the descriptor is applied to an element, usually these classes will be set on that element, however,\n * this depends on how the element converts the descriptor.\n *\n * @property {String} [id] Descriptor identifier. If not provided, it defaults to the converted marker's name.\n *\n * @property {Number} [priority] Descriptor priority. If not provided, it defaults to `10`. If the descriptor is used to create\n * an {@link module:engine/view/attributeelement~AttributeElement attribute element}, it will be that element's\n * {@link module:engine/view/attributeelement~AttributeElement#priority priority}. If the descriptor is applied to an element,\n * the priority will be used to determine which descriptor is more important.\n *\n * @property {Object} [attributes] Attributes to set. If the descriptor is used to create\n * an {@link module:engine/view/attributeelement~AttributeElement attribute element} over text nodes, these attributes will be set on that\n * attribute element. If the descriptor is applied to an element, usually these attributes will be set on that element, however,\n * this depends on how the element converts the descriptor.\n */\n","/**\n * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved.\n * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license\n */\n\nimport Matcher from '../view/matcher';\nimport ModelRange from '../model/range';\nimport ConversionHelpers from './conversionhelpers';\n\nimport { cloneDeep } from 'lodash-es';\nimport ModelSelection from '../model/selection';\n\n/**\n * Contains {@link module:engine/view/view view} to {@link module:engine/model/model model} converters for\n * {@link module:engine/conversion/upcastdispatcher~UpcastDispatcher}.\n *\n * @module engine/conversion/upcasthelpers\n */\n\n/**\n * Upcast conversion helper functions.\n *\n * @extends module:engine/conversion/conversionhelpers~ConversionHelpers\n */\nexport default class UpcastHelpers extends ConversionHelpers {\n\t/**\n\t * View element to model element conversion helper.\n\t *\n\t * This conversion results in creating a model element. For example,\n\t * view `Foo
` becomes `Foo` in the model.\n\t *\n\t * Keep in mind that the element will be inserted only if it is allowed\n\t * by {@link module:engine/model/schema~Schema schema} configuration.\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToElement( {\n\t *\t\t\tview: 'p',\n\t *\t\t\tmodel: 'paragraph'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToElement( {\n\t *\t\t\tview: 'p',\n\t *\t\t\tmodel: 'paragraph',\n\t *\t\t\tconverterPriority: 'high'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToElement( {\n\t *\t\t\tview: {\n\t *\t\t\t\tname: 'p',\n\t *\t\t\t\tclasses: 'fancy'\n\t *\t\t\t},\n\t *\t\t\tmodel: 'fancyParagraph'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToElement( {\n\t * \t\t\tview: {\n\t *\t\t\t\tname: 'p',\n\t *\t\t\t\tclasses: 'heading'\n\t * \t\t\t},\n\t * \t\t\tmodel: ( viewElement, modelWriter ) => {\n\t * \t\t\t\treturn modelWriter.createElement( 'heading', { level: viewElement.getAttribute( 'data-level' ) } );\n\t * \t\t\t}\n\t * \t\t} );\n\t *\n\t * See {@link module:engine/conversion/conversion~Conversion#for `conversion.for()`} to learn how to add a converter\n\t * to the conversion process.\n\t *\n\t * @method #elementToElement\n\t * @param {Object} config Conversion configuration.\n\t * @param {module:engine/view/matcher~MatcherPattern} [config.view] Pattern matching all view elements which should be converted. If not\n\t * set, the converter will fire for every view element.\n\t * @param {String|module:engine/model/element~Element|Function} config.model Name of the model element, a model element\n\t * instance or a function that takes a view element and returns a model element. The model element will be inserted in the model.\n\t * @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n\t * @returns {module:engine/conversion/upcasthelpers~UpcastHelpers}\n\t */\n\telementToElement( config ) {\n\t\treturn this.add( upcastElementToElement( config ) );\n\t}\n\n\t/**\n\t * View element to model attribute conversion helper.\n\t *\n\t * This conversion results in setting an attribute on a model node. For example, view `Foo` becomes\n\t * `Foo` {@link module:engine/model/text~Text model text node} with `bold` attribute set to `true`.\n\t *\n\t * This helper is meant to set a model attribute on all the elements that are inside the converted element:\n\t *\n\t *\t\tFoo --> Foo
--> <$text bold=\"true\">Foo$text>\n\t *\n\t * Above is a sample of HTML code, that goes through autoparagraphing (first step) and then is converted (second step).\n\t * Even though `` is over `` element, `bold=\"true\"` was added to the text. See\n\t * {@link module:engine/conversion/upcasthelpers~UpcastHelpers#attributeToAttribute} for comparison.\n\t *\n\t * Keep in mind that the attribute will be set only if it is allowed by {@link module:engine/model/schema~Schema schema} configuration.\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToAttribute( {\n\t *\t\t\tview: 'strong',\n\t *\t\t\tmodel: 'bold'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToAttribute( {\n\t *\t\t\tview: 'strong',\n\t *\t\t\tmodel: 'bold',\n\t *\t\t\tconverterPriority: 'high'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToAttribute( {\n\t *\t\t\tview: {\n\t *\t\t\t\tname: 'span',\n\t *\t\t\t\tclasses: 'bold'\n\t *\t\t\t},\n\t *\t\t\tmodel: 'bold'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToAttribute( {\n\t *\t\t\tview: {\n\t *\t\t\t\tname: 'span',\n\t *\t\t\t\tclasses: [ 'styled', 'styled-dark' ]\n\t *\t\t\t},\n\t *\t\t\tmodel: {\n\t *\t\t\t\tkey: 'styled',\n\t *\t\t\t\tvalue: 'dark'\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t * \t\teditor.conversion.for( 'upcast' ).elementToAttribute( {\n\t *\t\t\tview: {\n\t *\t\t\t\tname: 'span',\n\t *\t\t\t\tstyles: {\n\t *\t\t\t\t\t'font-size': /[\\s\\S]+/\n\t *\t\t\t\t}\n\t *\t\t\t},\n\t *\t\t\tmodel: {\n\t *\t\t\t\tkey: 'fontSize',\n\t *\t\t\t\tvalue: viewElement => {\n\t *\t\t\t\t\tconst fontSize = viewElement.getStyle( 'font-size' );\n\t *\t\t\t\t\tconst value = fontSize.substr( 0, fontSize.length - 2 );\n\t *\n\t *\t\t\t\t\tif ( value <= 10 ) {\n\t *\t\t\t\t\t\treturn 'small';\n\t *\t\t\t\t\t} else if ( value > 12 ) {\n\t *\t\t\t\t\t\treturn 'big';\n\t *\t\t\t\t\t}\n\t *\n\t *\t\t\t\t\treturn null;\n\t *\t\t\t\t}\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t * See {@link module:engine/conversion/conversion~Conversion#for `conversion.for()`} to learn how to add a converter\n\t * to the conversion process.\n\t *\n\t * @method #elementToAttribute\n\t * @param {Object} config Conversion configuration.\n\t * @param {module:engine/view/matcher~MatcherPattern} config.view Pattern matching all view elements which should be converted.\n\t * @param {String|Object} config.model Model attribute key or an object with `key` and `value` properties, describing\n\t * the model attribute. `value` property may be set as a function that takes a view element and returns the value.\n\t * If `String` is given, the model attribute value will be set to `true`.\n\t * @param {module:utils/priorities~PriorityString} [config.converterPriority='low'] Converter priority.\n\t * @returns {module:engine/conversion/upcasthelpers~UpcastHelpers}\n\t */\n\telementToAttribute( config ) {\n\t\treturn this.add( upcastElementToAttribute( config ) );\n\t}\n\n\t/**\n\t * View attribute to model attribute conversion helper.\n\t *\n\t * This conversion results in setting an attribute on a model node. For example, view `
` becomes\n\t * `` in the model.\n\t *\n\t * This helper is meant to convert view attributes from view elements which got converted to the model, so the view attribute\n\t * is set only on the corresponding model node:\n\t *\n\t *\t\t
--> \n\t *\n\t * Above, `class=\"dark\"` attribute is added only to the `` elements that has it. This is in contrary to\n\t * {@link module:engine/conversion/upcasthelpers~UpcastHelpers#elementToAttribute} which sets attributes for\n\t * all the children in the model:\n\t *\n\t *\t\t
Foo -->
Foo
-->
<$text bold=\"true\">Foo$text>\n\t *\n\t * Above is a sample of HTML code, that goes through autoparagraphing (first step) and then is converted (second step).\n\t * Even though `
` is over `` element, `bold=\"true\"` was added to the text.\n\t *\n\t * Keep in mind that the attribute will be set only if it is allowed by {@link module:engine/model/schema~Schema schema} configuration.\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).attributeToAttribute( {\n\t *\t\t\tview: 'src',\n\t *\t\t\tmodel: 'source'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).attributeToAttribute( {\n\t *\t\t\tview: { key: 'src' },\n\t *\t\t\tmodel: 'source'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).attributeToAttribute( {\n\t *\t\t\tview: { key: 'src' },\n\t *\t\t\tmodel: 'source',\n\t *\t\t\tconverterPriority: 'normal'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).attributeToAttribute( {\n\t *\t\t\tview: {\n\t *\t\t\t\tkey: 'data-style',\n\t *\t\t\t\tvalue: /[\\s\\S]+/\n\t *\t\t\t},\n\t *\t\t\tmodel: 'styled'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).attributeToAttribute( {\n\t *\t\t\tview: {\n\t *\t\t\t\tname: 'img',\n\t *\t\t\t\tkey: 'class',\n\t *\t\t\t\tvalue: 'styled-dark'\n\t *\t\t\t},\n\t *\t\t\tmodel: {\n\t *\t\t\t\tkey: 'styled',\n\t *\t\t\t\tvalue: 'dark'\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).attributeToAttribute( {\n\t *\t\t\tview: {\n\t *\t\t\t\tkey: 'class',\n\t *\t\t\t\tvalue: /styled-[\\S]+/\n\t *\t\t\t},\n\t *\t\t\tmodel: {\n\t *\t\t\t\tkey: 'styled'\n\t *\t\t\t\tvalue: viewElement => {\n\t *\t\t\t\t\tconst regexp = /styled-([\\S]+)/;\n\t *\t\t\t\t\tconst match = viewElement.getAttribute( 'class' ).match( regexp );\n\t *\n\t *\t\t\t\t\treturn match[ 1 ];\n\t *\t\t\t\t}\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t * Converting styles works a bit differently as it requires `view.styles` to be an object and by default\n\t * a model attribute will be set to `true` by such a converter. You can set the model attribute to any value by providing the `value`\n\t * callback that returns the desired value.\n\t *\n\t *\t\t// Default conversion of font-weight style will result in setting bold attribute to true.\n\t *\t\teditor.conversion.for( 'upcast' ).attributeToAttribute( {\n\t *\t\t\tview: {\n\t *\t\t\t\tstyles: {\n\t *\t\t\t\t\t'font-weight': 'bold'\n\t *\t\t\t\t}\n\t *\t\t\t},\n\t *\t\t\tmodel: 'bold'\n\t *\t\t} );\n\t *\n\t *\t\t// This converter will pass any style value to the `lineHeight` model attribute.\n\t *\t\teditor.conversion.for( 'upcast' ).attributeToAttribute( {\n\t *\t\t\tview: {\n\t *\t\t\t\tstyles: {\n\t *\t\t\t\t\t'line-height': /[\\s\\S]+/\n\t *\t\t\t\t}\n\t *\t\t\t},\n\t *\t\t\tmodel: {\n\t *\t\t\t\tkey: 'lineHeight',\n\t *\t\t\t\tvalue: viewElement => viewElement.getStyle( 'line-height' )\n\t *\t\t\t}\n\t *\t\t} );\n\t *\n\t * See {@link module:engine/conversion/conversion~Conversion#for `conversion.for()`} to learn how to add a converter\n\t * to the conversion process.\n\t *\n\t * @method #attributeToAttribute\n\t * @param {Object} config Conversion configuration.\n\t * @param {String|Object} config.view Specifies which view attribute will be converted. If a `String` is passed,\n\t * attributes with given key will be converted. If an `Object` is passed, it must have a required `key` property,\n\t * specifying view attribute key, and may have an optional `value` property, specifying view attribute value and optional `name`\n\t * property specifying a view element name from/on which the attribute should be converted. `value` can be given as a `String`,\n\t * a `RegExp` or a function callback, that takes view attribute value as the only parameter and returns `Boolean`.\n\t * @param {String|Object} config.model Model attribute key or an object with `key` and `value` properties, describing\n\t * the model attribute. `value` property may be set as a function that takes a view element and returns the value.\n\t * If `String` is given, the model attribute value will be same as view attribute value.\n\t * @param {module:utils/priorities~PriorityString} [config.converterPriority='low'] Converter priority.\n\t * @returns {module:engine/conversion/upcasthelpers~UpcastHelpers}\n\t */\n\tattributeToAttribute( config ) {\n\t\treturn this.add( upcastAttributeToAttribute( config ) );\n\t}\n\n\t/**\n\t * View element to model marker conversion helper.\n\t *\n\t * This conversion results in creating a model marker. For example, if the marker was stored in a view as an element:\n\t * `
Foo
Bar
`,\n\t * after the conversion is done, the marker will be available in\n\t * {@link module:engine/model/model~Model#markers model document markers}.\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToMarker( {\n\t *\t\t\tview: 'marker-search',\n\t *\t\t\tmodel: 'search'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToMarker( {\n\t *\t\t\tview: 'marker-search',\n\t *\t\t\tmodel: 'search',\n\t *\t\t\tconverterPriority: 'high'\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToMarker( {\n\t *\t\t\tview: 'marker-search',\n\t *\t\t\tmodel: viewElement => 'comment:' + viewElement.getAttribute( 'data-comment-id' )\n\t *\t\t} );\n\t *\n\t *\t\teditor.conversion.for( 'upcast' ).elementToMarker( {\n\t *\t\t\tview: {\n\t *\t\t\t\tname: 'span',\n\t *\t\t\t\tattributes: {\n\t *\t\t\t\t\t'data-marker': 'search'\n\t *\t\t\t\t}\n\t *\t\t\t},\n\t *\t\t\tmodel: 'search'\n\t *\t\t} );\n\t *\n\t * See {@link module:engine/conversion/conversion~Conversion#for `conversion.for()`} to learn how to add a converter\n\t * to the conversion process.\n\t *\n\t * @method #elementToMarker\n\t * @param {Object} config Conversion configuration.\n\t * @param {module:engine/view/matcher~MatcherPattern} config.view Pattern matching all view elements which should be converted.\n\t * @param {String|Function} config.model Name of the model marker, or a function that takes a view element and returns\n\t * a model marker name.\n\t * @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n\t * @returns {module:engine/conversion/upcasthelpers~UpcastHelpers}\n\t */\n\telementToMarker( config ) {\n\t\treturn this.add( upcastElementToMarker( config ) );\n\t}\n}\n\n/**\n * Function factory, creates a converter that converts {@link module:engine/view/documentfragment~DocumentFragment view document fragment}\n * or all children of {@link module:engine/view/element~Element} into\n * {@link module:engine/model/documentfragment~DocumentFragment model document fragment}.\n * This is the \"entry-point\" converter for upcast (view to model conversion). This converter starts the conversion of all children\n * of passed view document fragment. Those children {@link module:engine/view/node~Node view nodes} are then handled by other converters.\n *\n * This also a \"default\", last resort converter for all view elements that has not been converted by other converters.\n * When a view element is being converted to the model but it does not have converter specified, that view element\n * will be converted to {@link module:engine/model/documentfragment~DocumentFragment model document fragment} and returned.\n *\n * @returns {Function} Universal converter for view {@link module:engine/view/documentfragment~DocumentFragment fragments} and\n * {@link module:engine/view/element~Element elements} that returns\n * {@link module:engine/model/documentfragment~DocumentFragment model fragment} with children of converted view item.\n */\nexport function convertToModelFragment() {\n\treturn ( evt, data, conversionApi ) => {\n\t\t// Second argument in `consumable.consume` is discarded for ViewDocumentFragment but is needed for ViewElement.\n\t\tif ( !data.modelRange && conversionApi.consumable.consume( data.viewItem, { name: true } ) ) {\n\t\t\tconst { modelRange, modelCursor } = conversionApi.convertChildren( data.viewItem, data.modelCursor );\n\n\t\t\tdata.modelRange = modelRange;\n\t\t\tdata.modelCursor = modelCursor;\n\t\t}\n\t};\n}\n\n/**\n * Function factory, creates a converter that converts {@link module:engine/view/text~Text} to {@link module:engine/model/text~Text}.\n *\n * @returns {Function} {@link module:engine/view/text~Text View text} converter.\n */\nexport function convertText() {\n\treturn ( evt, data, conversionApi ) => {\n\t\tif ( conversionApi.schema.checkChild( data.modelCursor, '$text' ) ) {\n\t\t\tif ( conversionApi.consumable.consume( data.viewItem ) ) {\n\t\t\t\tconst text = conversionApi.writer.createText( data.viewItem.data );\n\n\t\t\t\tconversionApi.writer.insert( text, data.modelCursor );\n\n\t\t\t\tdata.modelRange = ModelRange._createFromPositionAndShift( data.modelCursor, text.offsetSize );\n\t\t\t\tdata.modelCursor = data.modelRange.end;\n\t\t\t}\n\t\t}\n\t};\n}\n\n/**\n * Function factory, creates a callback function which converts a {@link module:engine/view/selection~Selection\n * view selection} taken from the {@link module:engine/view/document~Document#event:selectionChange} event\n * and sets in on the {@link module:engine/model/document~Document#selection model}.\n *\n * **Note**: because there is no view selection change dispatcher nor any other advanced view selection to model\n * conversion mechanism, the callback should be set directly on view document.\n *\n *\t\tview.document.on( 'selectionChange', convertSelectionChange( modelDocument, mapper ) );\n *\n * @param {module:engine/model/model~Model} model Data model.\n * @param {module:engine/conversion/mapper~Mapper} mapper Conversion mapper.\n * @returns {Function} {@link module:engine/view/document~Document#event:selectionChange} callback function.\n */\nexport function convertSelectionChange( model, mapper ) {\n\treturn ( evt, data ) => {\n\t\tconst viewSelection = data.newSelection;\n\t\tconst modelSelection = new ModelSelection();\n\n\t\tconst ranges = [];\n\n\t\tfor ( const viewRange of viewSelection.getRanges() ) {\n\t\t\tranges.push( mapper.toModelRange( viewRange ) );\n\t\t}\n\n\t\tmodelSelection.setTo( ranges, { backward: viewSelection.isBackward } );\n\n\t\tif ( !modelSelection.isEqual( model.document.selection ) ) {\n\t\t\tmodel.change( writer => {\n\t\t\t\twriter.setSelection( modelSelection );\n\t\t\t} );\n\t\t}\n\t};\n}\n\n// View element to model element conversion helper.\n//\n// See {@link ~UpcastHelpers#elementToElement `.elementToElement()` upcast helper} for examples.\n//\n// @param {Object} config Conversion configuration.\n// @param {module:engine/view/matcher~MatcherPattern} [config.view] Pattern matching all view elements which should be converted. If not\n// set, the converter will fire for every view element.\n// @param {String|module:engine/model/element~Element|Function} config.model Name of the model element, a model element\n// instance or a function that takes a view element and returns a model element. The model element will be inserted in the model.\n// @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n// @returns {Function} Conversion helper.\nfunction upcastElementToElement( config ) {\n\tconfig = cloneDeep( config );\n\n\tconst converter = prepareToElementConverter( config );\n\n\tconst elementName = getViewElementNameFromConfig( config.view );\n\tconst eventName = elementName ? 'element:' + elementName : 'element';\n\n\treturn dispatcher => {\n\t\tdispatcher.on( eventName, converter, { priority: config.converterPriority || 'normal' } );\n\t};\n}\n\n// View element to model attribute conversion helper.\n//\n// See {@link ~UpcastHelpers#elementToAttribute `.elementToAttribute()` upcast helper} for examples.\n//\n// @param {Object} config Conversion configuration.\n// @param {module:engine/view/matcher~MatcherPattern} config.view Pattern matching all view elements which should be converted.\n// @param {String|Object} config.model Model attribute key or an object with `key` and `value` properties, describing\n// the model attribute. `value` property may be set as a function that takes a view element and returns the value.\n// If `String` is given, the model attribute value will be set to `true`.\n// @param {module:utils/priorities~PriorityString} [config.converterPriority='low'] Converter priority.\n// @returns {Function} Conversion helper.\nfunction upcastElementToAttribute( config ) {\n\tconfig = cloneDeep( config );\n\n\tnormalizeModelAttributeConfig( config );\n\n\tconst converter = prepareToAttributeConverter( config, false );\n\n\tconst elementName = getViewElementNameFromConfig( config.view );\n\tconst eventName = elementName ? 'element:' + elementName : 'element';\n\n\treturn dispatcher => {\n\t\tdispatcher.on( eventName, converter, { priority: config.converterPriority || 'low' } );\n\t};\n}\n\n// View attribute to model attribute conversion helper.\n//\n// See {@link ~UpcastHelpers#attributeToAttribute `.attributeToAttribute()` upcast helper} for examples.\n//\n// @param {Object} config Conversion configuration.\n// @param {String|Object} config.view Specifies which view attribute will be converted. If a `String` is passed,\n// attributes with given key will be converted. If an `Object` is passed, it must have a required `key` property,\n// specifying view attribute key, and may have an optional `value` property, specifying view attribute value and optional `name`\n// property specifying a view element name from/on which the attribute should be converted. `value` can be given as a `String`,\n// a `RegExp` or a function callback, that takes view attribute value as the only parameter and returns `Boolean`.\n// @param {String|Object} config.model Model attribute key or an object with `key` and `value` properties, describing\n// the model attribute. `value` property may be set as a function that takes a view element and returns the value.\n// If `String` is given, the model attribute value will be same as view attribute value.\n// @param {module:utils/priorities~PriorityString} [config.converterPriority='low'] Converter priority.\n// @returns {Function} Conversion helper.\nfunction upcastAttributeToAttribute( config ) {\n\tconfig = cloneDeep( config );\n\n\tlet viewKey = null;\n\n\tif ( typeof config.view == 'string' || config.view.key ) {\n\t\tviewKey = normalizeViewAttributeKeyValueConfig( config );\n\t}\n\n\tnormalizeModelAttributeConfig( config, viewKey );\n\n\tconst converter = prepareToAttributeConverter( config, true );\n\n\treturn dispatcher => {\n\t\tdispatcher.on( 'element', converter, { priority: config.converterPriority || 'low' } );\n\t};\n}\n\n// View element to model marker conversion helper.\n//\n// See {@link ~UpcastHelpers#elementToMarker `.elementToMarker()` upcast helper} for examples.\n//\n// @param {Object} config Conversion configuration.\n// @param {module:engine/view/matcher~MatcherPattern} config.view Pattern matching all view elements which should be converted.\n// @param {String|Function} config.model Name of the model marker, or a function that takes a view element and returns\n// a model marker name.\n// @param {module:utils/priorities~PriorityString} [config.converterPriority='normal'] Converter priority.\n// @returns {Function} Conversion helper.\nfunction upcastElementToMarker( config ) {\n\tconfig = cloneDeep( config );\n\n\tnormalizeToMarkerConfig( config );\n\n\treturn upcastElementToElement( config );\n}\n\n// Helper function for from-view-element conversion. Checks if `config.view` directly specifies converted view element's name\n// and if so, returns it.\n//\n// @param {Object} config Conversion view config.\n// @returns {String|null} View element name or `null` if name is not directly set.\nfunction getViewElementNameFromConfig( viewConfig ) {\n\tif ( typeof viewConfig == 'string' ) {\n\t\treturn viewConfig;\n\t}\n\n\tif ( typeof viewConfig == 'object' && typeof viewConfig.name == 'string' ) {\n\t\treturn viewConfig.name;\n\t}\n\n\treturn null;\n}\n\n// Helper for to-model-element conversion. Takes a config object and returns a proper converter function.\n//\n// @param {Object} config Conversion configuration.\n// @returns {Function} View to model converter.\nfunction prepareToElementConverter( config ) {\n\tconst matcher = config.view ? new Matcher( config.view ) : null;\n\n\treturn ( evt, data, conversionApi ) => {\n\t\tlet match = {};\n\n\t\t// If `config.view` has not been passed do not try matching. In this case, the converter should fire for all elements.\n\t\tif ( matcher ) {\n\t\t\t// This will be usually just one pattern but we support matchers with many patterns too.\n\t\t\tconst matcherResult = matcher.match( data.viewItem );\n\n\t\t\t// If there is no match, this callback should not do anything.\n\t\t\tif ( !matcherResult ) {\n\t\t\t\treturn;\n\t\t\t}\n\n\t\t\tmatch = matcherResult.match;\n\t\t}\n\n\t\t// Force consuming element's name.\n\t\tmatch.name = true;\n\n\t\t// Create model element basing on config.\n\t\tconst modelElement = getModelElement( config.model, data.viewItem, conversionApi.writer );\n\n\t\t// Do not convert if element building function returned falsy value.\n\t\tif ( !modelElement ) {\n\t\t\treturn;\n\t\t}\n\n\t\t// When element was already consumed then skip it.\n\t\tif ( !conversionApi.consumable.test( data.viewItem, match ) ) {\n\t\t\treturn;\n\t\t}\n\n\t\t// Find allowed parent for element that we are going to insert.\n\t\t// If current parent does not allow to insert element but one of the ancestors does\n\t\t// then split nodes to allowed parent.\n\t\tconst splitResult = conversionApi.splitToAllowedParent( modelElement, data.modelCursor );\n\n\t\t// When there is no split result it means that we can't insert element to model tree, so let's skip it.\n\t\tif ( !splitResult ) {\n\t\t\treturn;\n\t\t}\n\n\t\t// Insert element on allowed position.\n\t\tconversionApi.writer.insert( modelElement, splitResult.position );\n\n\t\t// Convert children and insert to element.\n\t\tconversionApi.convertChildren( data.viewItem, conversionApi.writer.createPositionAt( modelElement, 0 ) );\n\n\t\t// Consume appropriate value from consumable values list.\n\t\tconversionApi.consumable.consume( data.viewItem, match );\n\n\t\tconst parts = conversionApi.getSplitParts( modelElement );\n\n\t\t// Set conversion result range.\n\t\tdata.modelRange = new ModelRange(\n\t\t\tconversionApi.writer.createPositionBefore( modelElement ),\n\t\t\tconversionApi.writer.createPositionAfter( parts[ parts.length - 1 ] )\n\t\t);\n\n\t\t// Now we need to check where the `modelCursor` should be.\n\t\tif ( splitResult.cursorParent ) {\n\t\t\t// If we split parent to insert our element then we want to continue conversion in the new part of the split parent.\n\t\t\t//\n\t\t\t// before: foo[]\n\t\t\t// after: foo[]\n\n\t\t\tdata.modelCursor = conversionApi.writer.createPositionAt( splitResult.cursorParent, 0 );\n\t\t} else {\n\t\t\t// Otherwise just continue after inserted element.\n\n\t\t\tdata.modelCursor = data.modelRange.end;\n\t\t}\n\t};\n}\n\n// Helper function for upcasting-to-element converter. Takes the model configuration, the converted view element\n// and a writer instance and returns a model element instance to be inserted in the model.\n//\n// @param {String|Function|module:engine/model/element~Element} model Model conversion configuration.\n// @param {module:engine/view/node~Node} input The converted view node.\n// @param {module:engine/model/writer~Writer} writer A writer instance to use to create the model element.\nfunction getModelElement( model, input, writer ) {\n\tif ( model instanceof Function ) {\n\t\treturn model( input, writer );\n\t} else {\n\t\treturn writer.createElement( model );\n\t}\n}\n\n// Helper function view-attribute-to-model-attribute helper. Normalizes `config.view` which was set as `String` or\n// as an `Object` with `key`, `value` and `name` properties. Normalized `config.view` has is compatible with\n// {@link module:engine/view/matcher~MatcherPattern}.\n//\n// @param {Object} config Conversion config.\n// @returns {String} Key of the converted view attribute.\nfunction normalizeViewAttributeKeyValueConfig( config ) {\n\tif ( typeof config.view == 'string' ) {\n\t\tconfig.view = { key: config.view };\n\t}\n\n\tconst key = config.view.key;\n\tlet normalized;\n\n\tif ( key == 'class' || key == 'style' ) {\n\t\tconst keyName = key == 'class' ? 'classes' : 'styles';\n\n\t\tnormalized = {\n\t\t\t[ keyName ]: config.view.value\n\t\t};\n\t} else {\n\t\tconst value = typeof config.view.value == 'undefined' ? /[\\s\\S]*/ : config.view.value;\n\n\t\tnormalized = {\n\t\t\tattributes: {\n\t\t\t\t[ key ]: value\n\t\t\t}\n\t\t};\n\t}\n\n\tif ( config.view.name ) {\n\t\tnormalized.name = config.view.name;\n\t}\n\n\tconfig.view = normalized;\n\n\treturn key;\n}\n\n// Helper function that normalizes `config.model` in from-model-attribute conversion. `config.model` can be set\n// as a `String`, an `Object` with only `key` property or an `Object` with `key` and `value` properties. Normalized\n// `config.model` is an `Object` with `key` and `value` properties.\n//\n// @param {Object} config Conversion config.\n// @param {String} viewAttributeKeyToCopy Key of the converted view attribute. If it is set, model attribute value\n// will be equal to view attribute value.\nfunction normalizeModelAttributeConfig( config, viewAttributeKeyToCopy = null ) {\n\tconst defaultModelValue = viewAttributeKeyToCopy === null ? true : viewElement => viewElement.getAttribute( viewAttributeKeyToCopy );\n\n\tconst key = typeof config.model != 'object' ? config.model : config.model.key;\n\tconst value = typeof config.model != 'object' || typeof config.model.value == 'undefined' ? defaultModelValue : config.model.value;\n\n\tconfig.model = { key, value };\n}\n\n// Helper for to-model-attribute conversion. Takes the model attribute name and conversion configuration and returns\n// a proper converter function.\n//\n// @param {String} modelAttributeKey The key of the model attribute to set on a model node.\n// @param {Object|Array.