/** * @license Copyright (c) 2003-2019, CKSource - Frederico Knabben. All rights reserved. * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license */ /** * @module engine/model/node */ import toMap from '@ckeditor/ckeditor5-utils/src/tomap'; import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror'; import compareArrays from '@ckeditor/ckeditor5-utils/src/comparearrays'; // To check if component is loaded more than once. import '@ckeditor/ckeditor5-utils/src/version'; /** * Model node. Most basic structure of model tree. * * This is an abstract class that is a base for other classes representing different nodes in model. * * **Note:** If a node is detached from the model tree, you can manipulate it using it's API. * However, it is **very important** that nodes already attached to model tree should be only changed through * {@link module:engine/model/writer~Writer Writer API}. * * Changes done by `Node` methods, like {@link module:engine/model/element~Element#_insertChild _insertChild} or * {@link module:engine/model/node~Node#_setAttribute _setAttribute} * do not generate {@link module:engine/model/operation/operation~Operation operations} * which are essential for correct editor work if you modify nodes in {@link module:engine/model/document~Document document} root. * * The flow of working on `Node` (and classes that inherits from it) is as such: * 1. You can create a `Node` instance, modify it using it's API. * 2. Add `Node` to the model using `Batch` API. * 3. Change `Node` that was already added to the model using `Batch` API. * * Similarly, you cannot use `Batch` API on a node that has not been added to the model tree, with the exception * of {@link module:engine/model/writer~Writer#insert inserting} that node to the model tree. * * Be aware that using {@link module:engine/model/writer~Writer#remove remove from Batch API} does not allow to use `Node` API because * the information about `Node` is still kept in model document. * * In case of {@link module:engine/model/element~Element element node}, adding and removing children also counts as changing a node and * follows same rules. */ export default class Node { /** * Creates a model node. * * This is an abstract class, so this constructor should not be used directly. * * @abstract * @param {Object} [attrs] Node's attributes. See {@link module:utils/tomap~toMap} for a list of accepted values. */ constructor( attrs ) { /** * Parent of this node. It could be {@link module:engine/model/element~Element} * or {@link module:engine/model/documentfragment~DocumentFragment}. * Equals to `null` if the node has no parent. * * @readonly * @member {module:engine/model/element~Element|module:engine/model/documentfragment~DocumentFragment|null} */ this.parent = null; /** * Attributes set on this node. * * @private * @member {Map} module:engine/model/node~Node#_attrs */ this._attrs = toMap( attrs ); } /** * Index of this node in it's parent 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 model tree got broken. * * @readonly * @type {Number|null} */ get index() { let pos; if ( !this.parent ) { return null; } if ( ( pos = this.parent.getChildIndex( this ) ) === null ) { throw new CKEditorError( 'model-node-not-found-in-parent: The node\'s parent does not contain this node.', this ); } return pos; } /** * Offset at which this node starts in it's parent. It is equal to the sum of {@link #offsetSize offsetSize} * of all it's previous siblings. Equals to `null` if node has no parent. * * Accessing this property throws an error if this node's parent element does not contain it. * This means that model tree got broken. * * @readonly * @type {Number|null} */ get startOffset() { let pos; if ( !this.parent ) { return null; } if ( ( pos = this.parent.getChildStartOffset( this ) ) === null ) { throw new CKEditorError( 'model-node-not-found-in-parent: The node\'s parent does not contain this node.', this ); } return pos; } /** * Offset size of this node. Represents how much "offset space" is occupied by the node in it's parent. * It is important for {@link module:engine/model/position~Position position}. When node has `offsetSize` greater than `1`, position * can be placed between that node start and end. `offsetSize` greater than `1` is for nodes that represents more * than one entity, i.e. {@link module:engine/model/text~Text text node}. * * @readonly * @type {Number} */ get offsetSize() { return 1; } /** * Offset at which this node ends in it's parent. It is equal to the sum of this node's * {@link module:engine/model/node~Node#startOffset start offset} and {@link #offsetSize offset size}. * Equals to `null` if the node has no parent. * * @readonly * @type {Number|null} */ get endOffset() { if ( !this.parent ) { return null; } return this.startOffset + this.offsetSize; } /** * Node's next sibling or `null` if the node is a last child of it's parent or if the node has no parent. * * @readonly * @type {module:engine/model/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 the node is a first child of it's parent or if the node has no parent. * * @readonly * @type {module:engine/model/node~Node|null} */ get previousSibling() { const index = this.index; return ( index !== null && this.parent.getChild( index - 1 ) ) || null; } /** * The top-most ancestor of the node. If node has no parent it is the root itself. If the node is a part * of {@link module:engine/model/documentfragment~DocumentFragment}, it's `root` is equal to that `DocumentFragment`. * * @readonly * @type {module:engine/model/node~Node|module:engine/model/documentfragment~DocumentFragment} */ get root() { let root = this; // eslint-disable-line consistent-this while ( root.parent ) { root = root.parent; } return root; } /** * {@link module:engine/model/document~Document Document} that owns this node or `null` if the node has no parent or is inside * a {@link module:engine/model/documentfragment~DocumentFragment DocumentFragment}. * * @readonly * @type {module:engine/model/document~Document|null} */ get document() { // This is a top element of a sub-tree. if ( this.root == this ) { return null; } // Root may be `DocumentFragment` which does not have document property. return this.root.document || null; } /** * Gets path to the node. The path is an array containing starting offsets of consecutive ancestors of this node, * beginning from {@link module:engine/model/node~Node#root root}, down to this node's starting offset. The path can be used to * create {@link module:engine/model/position~Position Position} instance. * * const abc = new Text( 'abc' ); * const foo = new Text( 'foo' ); * const h1 = new Element( 'h1', null, new Text( 'header' ) ); * const p = new Element( 'p', null, [ abc, foo ] ); * const div = new Element( '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.} The path. */ getPath() { const path = []; let node = this; // eslint-disable-line consistent-this while ( node.parent ) { path.unshift( node.startOffset ); 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/model/element~Element} or {@link module:engine/model/documentfragment~DocumentFragment} * which is a common ancestor of both nodes. * * @param {module:engine/model/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/model/element~Element|module:engine/model/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/model/documentfragment~DocumentFragment}s). * * @param {module:engine/model/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/model/documentfragment~DocumentFragment}s). * * @param {module:engine/model/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 ); } /** * Checks if the node has an attribute with given key. * * @param {String} key Key of attribute to check. * @returns {Boolean} `true` if attribute with given key is set on node, `false` otherwise. */ hasAttribute( key ) { return this._attrs.has( key ); } /** * Gets an attribute value for given key or `undefined` if that attribute is not set on node. * * @param {String} key Key of attribute to look for. * @returns {*} Attribute value or `undefined`. */ getAttribute( key ) { return this._attrs.get( key ); } /** * Returns iterator that iterates over this node's attributes. * * Attributes are returned as arrays containing two items. First one is attribute key and second is attribute value. * This format is accepted by native `Map` object and also can be passed in `Node` constructor. * * @returns {Iterable.<*>} */ getAttributes() { return this._attrs.entries(); } /** * Returns iterator that iterates over this node's attribute keys. * * @returns {Iterable.} */ getAttributeKeys() { return this._attrs.keys(); } /** * Converts `Node` to plain object and returns it. * * @returns {Object} `Node` converted to plain object. */ toJSON() { const json = {}; // Serializes attributes to the object. // attributes = { a: 'foo', b: 1, c: true }. if ( this._attrs.size ) { json.attributes = Array.from( this._attrs ).reduce( ( result, attr ) => { result[ attr[ 0 ] ] = attr[ 1 ]; return result; }, {} ); } return json; } /** * Creates a copy of this node, that is a node with exactly same attributes, and returns it. * * @protected * @returns {module:engine/model/node~Node} Node with same attributes as this node. */ _clone() { return new Node( this._attrs ); } /** * Removes this node from it's parent. * * @see module:engine/model/writer~Writer#remove * @protected */ _remove() { this.parent._removeChildren( this.index ); } /** * Sets attribute on the node. If attribute with the same key already is set, it's value is overwritten. * * @see module:engine/model/writer~Writer#setAttribute * @protected * @param {String} key Key of attribute to set. * @param {*} value Attribute value. */ _setAttribute( key, value ) { this._attrs.set( key, value ); } /** * Removes all attributes from the node and sets given attributes. * * @see module:engine/model/writer~Writer#setAttributes * @protected * @param {Object} [attrs] Attributes to set. See {@link module:utils/tomap~toMap} for a list of accepted values. */ _setAttributesTo( attrs ) { this._attrs = toMap( attrs ); } /** * Removes an attribute with given key from the node. * * @see module:engine/model/writer~Writer#removeAttribute * @protected * @param {String} key Key of attribute to remove. * @returns {Boolean} `true` if the attribute was set on the element, `false` otherwise. */ _removeAttribute( key ) { return this._attrs.delete( key ); } /** * Removes all attributes from the node. * * @see module:engine/model/writer~Writer#clearAttributes * @protected */ _clearAttributes() { this._attrs.clear(); } /** * Checks whether given model tree object is of given type. * * This method is useful when processing model tree objects that are of unknown type. For example, a function * may return {@link module:engine/model/documentfragment~DocumentFragment} or {@link module:engine/model/node~Node} * that can be either text node or element. This method can be used to check what kind of object is returned. * All checked types might be prefixed with `model:` to narrow search exclusively to model's objects. * That should prevent of situation where `view:node` accidentally might be considered as `model:node`. * * obj.is( 'node' ); // true for any node, false for document fragment and text fragment * obj.is( 'documentFragment' ); // true for document fragment, false for any node * obj.is( 'element' ); // true for any element, false for text node or document fragment * obj.is( 'element', 'paragraph' ); // true only for element which name is 'paragraph' * obj.is( 'paragraph' ); // shortcut for obj.is( 'element', 'paragraph' ) * obj.is( 'text' ); // true for text node, false for element and document fragment * obj.is( 'textProxy' ); // true for text proxy object * * @method #is * @param {String} type * @returns {Boolean} */ is( type ) { return type == 'node' || type == 'model:node'; } } /** * The node's parent does not contain this node. * * This error may be thrown from corrupted trees. * * @error model-node-not-found-in-parent */