src/view/node.js
/**
* @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
*/
/**
* @module engine/view/node
*/
import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';
import EmitterMixin from '@ckeditor/ckeditor5-utils/src/emittermixin';
import mix from '@ckeditor/ckeditor5-utils/src/mix';
import compareArrays from '@ckeditor/ckeditor5-utils/src/comparearrays';
import { clone } from 'lodash-es';
// To check if component is loaded more than once.
import '@ckeditor/ckeditor5-utils/src/version';
/**
* Abstract view node class.
*
* This is an abstract class. Its constructor should not be used directly.
* Use the {@link module:engine/view/downcastwriter~DowncastWriter} or {@link module:engine/view/upcastwriter~UpcastWriter}
* to create new instances of view nodes.
*
* @abstract
*/
export default class Node {
/**
* Creates a tree view node.
*
* @protected
* @param {module:engine/view/document~Document} document The document instance to which this node belongs.
*/
constructor( document ) {
/**
* The document instance to which this node belongs.
*
* @readonly
* @member {module:engine/view/document~Document}
*/
this.document = document;
/**
* Parent element. Null by default. Set by {@link module:engine/view/element~Element#_insertChild}.
*
* @readonly
* @member {module:engine/view/element~Element|module:engine/view/documentfragment~DocumentFragment|null}
*/
this.parent = null;
}
/**
* Index of the node in the parent element or null if the node has no parent.
*
* Accessing this property throws an error if this node's parent element does not contain it.
* This means that view tree got broken.
*
* @readonly
* @type {Number|null}
*/
get index() {
let pos;
if ( !this.parent ) {
return null;
}
// No parent or child doesn't exist in parent's children.
if ( ( pos = this.parent.getChildIndex( this ) ) == -1 ) {
/**
* The node's parent does not contain this node. It means that the document tree is corrupted.
*
* @error view-node-not-found-in-parent
*/
throw new CKEditorError( 'view-node-not-found-in-parent: The node\'s parent does not contain this node.', this );
}
return pos;
}
/**
* Node's next sibling, or `null` if it is the last child.
*
* @readonly
* @type {module:engine/view/node~Node|null}
*/
get nextSibling() {
const index = this.index;
return ( index !== null && this.parent.getChild( index + 1 ) ) || null;
}
/**
* Node's previous sibling, or `null` if it is the first child.
*
* @readonly
* @type {module:engine/view/node~Node|null}
*/
get previousSibling() {
const index = this.index;
return ( index !== null && this.parent.getChild( index - 1 ) ) || null;
}
/**
* Top-most ancestor of the node. If the node has no parent it is the root itself.
*
* @readonly
* @type {module:engine/view/node~Node|module:engine/view/documentfragment~DocumentFragment}
*/
get root() {
let root = this; // eslint-disable-line consistent-this
while ( root.parent ) {
root = root.parent;
}
return root;
}
/**
* Returns true if the node is in a tree rooted in the document (is a descendant of one of its roots).
*
* @returns {Boolean}
*/
isAttached() {
return this.root.is( 'rootElement' );
}
/**
* Gets a path to the node. The path is an array containing indices of consecutive ancestors of this node,
* beginning from {@link module:engine/view/node~Node#root root}, down to this node's index.
*
* const abc = downcastWriter.createText( 'abc' );
* const foo = downcastWriter.createText( 'foo' );
* const h1 = downcastWriter.createElement( 'h1', null, downcastWriter.createText( 'header' ) );
* const p = downcastWriter.createElement( 'p', null, [ abc, foo ] );
* const div = downcastWriter.createElement( 'div', null, [ h1, p ] );
* foo.getPath(); // Returns [ 1, 3 ]. `foo` is in `p` which is in `div`. `p` starts at offset 1, while `foo` at 3.
* h1.getPath(); // Returns [ 0 ].
* div.getPath(); // Returns [].
*
* @returns {Array.<Number>} The path.
*/
getPath() {
const path = [];
let node = this; // eslint-disable-line consistent-this
while ( node.parent ) {
path.unshift( node.index );
node = node.parent;
}
return path;
}
/**
* Returns ancestors array of this node.
*
* @param {Object} options Options object.
* @param {Boolean} [options.includeSelf=false] When set to `true` this node will be also included in parent's array.
* @param {Boolean} [options.parentFirst=false] When set to `true`, array will be sorted from node's parent to root element,
* otherwise root element will be the first item in the array.
* @returns {Array} Array with ancestors.
*/
getAncestors( options = { includeSelf: false, parentFirst: false } ) {
const ancestors = [];
let parent = options.includeSelf ? this : this.parent;
while ( parent ) {
ancestors[ options.parentFirst ? 'push' : 'unshift' ]( parent );
parent = parent.parent;
}
return ancestors;
}
/**
* Returns a {@link module:engine/view/element~Element} or {@link module:engine/view/documentfragment~DocumentFragment}
* which is a common ancestor of both nodes.
*
* @param {module:engine/view/node~Node} node The second node.
* @param {Object} options Options object.
* @param {Boolean} [options.includeSelf=false] When set to `true` both nodes will be considered "ancestors" too.
* Which means that if e.g. node A is inside B, then their common ancestor will be B.
* @returns {module:engine/view/element~Element|module:engine/view/documentfragment~DocumentFragment|null}
*/
getCommonAncestor( node, options = {} ) {
const ancestorsA = this.getAncestors( options );
const ancestorsB = node.getAncestors( options );
let i = 0;
while ( ancestorsA[ i ] == ancestorsB[ i ] && ancestorsA[ i ] ) {
i++;
}
return i === 0 ? null : ancestorsA[ i - 1 ];
}
/**
* Returns whether this node is before given node. `false` is returned if nodes are in different trees (for example,
* in different {@link module:engine/view/documentfragment~DocumentFragment}s).
*
* @param {module:engine/view/node~Node} node Node to compare with.
* @returns {Boolean}
*/
isBefore( node ) {
// Given node is not before this node if they are same.
if ( this == node ) {
return false;
}
// Return `false` if it is impossible to compare nodes.
if ( this.root !== node.root ) {
return false;
}
const thisPath = this.getPath();
const nodePath = node.getPath();
const result = compareArrays( thisPath, nodePath );
switch ( result ) {
case 'prefix':
return true;
case 'extension':
return false;
default:
return thisPath[ result ] < nodePath[ result ];
}
}
/**
* Returns whether this node is after given node. `false` is returned if nodes are in different trees (for example,
* in different {@link module:engine/view/documentfragment~DocumentFragment}s).
*
* @param {module:engine/view/node~Node} node Node to compare with.
* @returns {Boolean}
*/
isAfter( node ) {
// Given node is not before this node if they are same.
if ( this == node ) {
return false;
}
// Return `false` if it is impossible to compare nodes.
if ( this.root !== node.root ) {
return false;
}
// In other cases, just check if the `node` is before, and return the opposite.
return !this.isBefore( node );
}
/**
* Removes node from parent.
*
* @protected
*/
_remove() {
this.parent._removeChildren( this.index );
}
/**
* @protected
* @param {module:engine/view/document~ChangeType} type Type of the change.
* @param {module:engine/view/node~Node} node Changed node.
* @fires change
*/
_fireChange( type, node ) {
this.fire( 'change:' + type, node );
if ( this.parent ) {
this.parent._fireChange( type, node );
}
}
/**
* Custom toJSON method to solve child-parent circular dependencies.
*
* @returns {Object} Clone of this object with the parent property removed.
*/
toJSON() {
const json = clone( this );
// Due to circular references we need to remove parent reference.
delete json.parent;
return json;
}
/**
* Checks whether this object is of the given type.
*
* This method is useful when processing view objects that are of unknown type. For example, a function
* may return a {@link module:engine/view/documentfragment~DocumentFragment} or a {@link module:engine/view/node~Node}
* that can be either a text node or an element. This method can be used to check what kind of object is returned.
*
* someObject.is( 'element' ); // -> true if this is an element
* someObject.is( 'node' ); // -> true if this is a node (a text node or an element)
* someObject.is( 'documentFragment' ); // -> true if this is a document fragment
*
* Since this method is also available on a range of model objects, you can prefix the type of the object with
* `model:` or `view:` to check, for example, if this is the model's or view's element:
*
* viewElement.is( 'view:element' ); // -> true
* viewElement.is( 'model:element' ); // -> false
*
* By using this method it is also possible to check a name of an element:
*
* imgElement.is( 'img' ); // -> true
* imgElement.is( 'element', 'img' ); // -> same as above
* imgElement.is( 'view:element', 'img' ); // -> same as above, but more precise
*
* The list of view objects which implement the `is()` method:
*
* * {@link module:engine/view/attributeelement~AttributeElement#is `AttributeElement#is()`}
* * {@link module:engine/view/containerelement~ContainerElement#is `ContainerElement#is()`}
* * {@link module:engine/view/documentfragment~DocumentFragment#is `DocumentFragment#is()`}
* * {@link module:engine/view/documentselection~DocumentSelection#is `DocumentSelection#is()`}
* * {@link module:engine/view/editableelement~EditableElement#is `EditableElement#is()`}
* * {@link module:engine/view/element~Element#is `Element#is()`}
* * {@link module:engine/view/emptyelement~EmptyElement#is `EmptyElement#is()`}
* * {@link module:engine/view/node~Node#is `Node#is()`}
* * {@link module:engine/view/position~Position#is `Position#is()`}
* * {@link module:engine/view/range~Range#is `Range#is()`}
* * {@link module:engine/view/rooteditableelement~RootEditableElement#is `RootEditableElement#is()`}
* * {@link module:engine/view/selection~Selection#is `Selection#is()`}
* * {@link module:engine/view/text~Text#is `Text#is()`}
* * {@link module:engine/view/textproxy~TextProxy#is `TextProxy#is()`}
* * {@link module:engine/view/uielement~UIElement#is `UIElement#is()`}
*
* @method #is
* @param {String} type
* @returns {Boolean}
*/
is( type ) {
return type === 'node' || type === 'view:node';
}
/**
* Clones this node.
*
* @protected
* @method #_clone
* @returns {module:engine/view/node~Node} Clone of this node.
*/
/**
* Checks if provided node is similar to this node.
*
* @method #isSimilar
* @returns {Boolean} True if nodes are similar.
*/
}
/**
* Fired when list of {@link module:engine/view/element~Element elements} children changes.
*
* Change event is bubbled – it is fired on all ancestors.
*
* @event change:children
* @param {module:engine/view/node~Node} changedNode
*/
/**
* Fired when list of {@link module:engine/view/element~Element elements} attributes changes.
*
* Change event is bubbled – it is fired on all ancestors.
*
* @event change:attributes
* @param {module:engine/view/node~Node} changedNode
*/
/**
* Fired when {@link module:engine/view/text~Text text nodes} data changes.
*
* Change event is bubbled – it is fired on all ancestors.
*
* @event change:text
* @param {module:engine/view/node~Node} changedNode
*/
/**
* @event change
*/
mix( Node, EmitterMixin );