@ckeditor/ckeditor5-engine
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The editing engine of CKEditor 5 – the best browser-based rich text editor.
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JavaScript
/**
* @license Copyright (c) 2003-2025, CKSource Holding sp. z o.o. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
*/
/* eslint-disable @typescript-eslint/no-unused-vars */
/**
* @module engine/model/node
*/
import { ModelTypeCheckable } from './typecheckable.js';
import { compareArrays, toMap } from '@ckeditor/ckeditor5-utils';
/**
* 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~ModelWriter Writer API}.
*
* Changes done by `Node` methods, like {@link module:engine/model/element~ModelElement#_insertChild _insertChild} or
* {@link module:engine/model/node~ModelNode#_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~ModelDocument 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~ModelWriter#insert inserting} that node to the model tree.
*
* Be aware that using {@link module:engine/model/writer~ModelWriter#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~ModelElement element node}, adding and removing children also counts as changing a node and
* follows same rules.
*/
export class ModelNode extends ModelTypeCheckable {
/**
* Parent of this node. It could be {@link module:engine/model/element~ModelElement}
* or {@link module:engine/model/documentfragment~ModelDocumentFragment}.
* Equals to `null` if the node has no parent.
*/
parent = null;
/**
* Attributes set on this node.
*/
_attrs;
/**
* Index of this node in its parent or `null` if the node has no parent.
*
* @internal
*/
_index = null;
/**
* Offset at which this node starts in its parent or `null` if the node has no parent.
*
* @internal
*/
_startOffset = null;
/**
* Creates a model node.
*
* This is an abstract class, so this constructor should not be used directly.
*
* @param attrs Node's attributes. See {@link module:utils/tomap~toMap} for a list of accepted values.
*/
constructor(attrs) {
super();
this._attrs = toMap(attrs);
}
/**
* {@link module:engine/model/document~ModelDocument Document} that owns this root element.
*/
get document() {
return null;
}
/**
* Index of this node in its parent or `null` if the node has no parent.
*/
get index() {
return this._index;
}
/**
* Offset at which this node starts in its parent. It is equal to the sum of {@link #offsetSize offsetSize}
* of all its previous siblings. Equals to `null` if node has no parent.
*/
get startOffset() {
return this._startOffset;
}
/**
* Offset size of this node.
*
* Represents how much "offset space" is occupied by the node in its parent. It is important for
* {@link module:engine/model/position~ModelPosition 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. a {@link module:engine/model/text~ModelText text node}.
*/
get offsetSize() {
return 1;
}
/**
* Offset at which this node ends in its parent. It is equal to the sum of this node's
* {@link module:engine/model/node~ModelNode#startOffset start offset} and {@link #offsetSize offset size}.
* Equals to `null` if the node has no parent.
*/
get endOffset() {
if (this.startOffset === null) {
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.
*/
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.
*/
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~ModelDocumentFragment}, it's `root` is equal to that `DocumentFragment`.
*/
get root() {
// eslint-disable-next-line @typescript-eslint/no-this-alias, consistent-this
let root = this;
while (root.parent) {
root = root.parent;
}
return root;
}
/**
* Returns `true` if the node is inside a document root that is attached to the document.
*/
isAttached() {
// If the node has no parent it means that it is a root.
// But this is not a `RootElement`, so it means that it is not attached.
//
// If this is not the root, check if this element's root is attached.
return this.parent === null ? false : this.root.isAttached();
}
/**
* 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~ModelNode#root root}, down to this node's starting offset. The path can be used to
* create {@link module:engine/model/position~ModelPosition Position} instance.
*
* ```ts
* const abc = new Text( 'abc' );
* const foo = new Text( 'foo' );
* const h1 = new ModelElement( 'h1', null, new Text( 'header' ) );
* const p = new ModelElement( 'p', null, [ abc, foo ] );
* const div = new ModelElement( '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 [].
* ```
*/
getPath() {
const path = [];
// eslint-disable-next-line @typescript-eslint/no-this-alias, consistent-this
let node = this;
while (node.parent) {
path.unshift(node.startOffset);
node = node.parent;
}
return path;
}
/**
* Returns ancestors array of this node.
*
* @param options Options object.
* @param options.includeSelf When set to `true` this node will be also included in parent's array.
* @param options.parentFirst 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 with ancestors.
*/
getAncestors(options = {}) {
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~ModelElement} or {@link module:engine/model/documentfragment~ModelDocumentFragment}
* which is a common ancestor of both nodes.
*
* @param node The second node.
* @param options Options object.
* @param options.includeSelf 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.
*/
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~ModelDocumentFragment}s).
*
* @param node Node to compare with.
*/
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~ModelDocumentFragment}s).
*
* @param node Node to compare with.
*/
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 key Key of attribute to check.
* @returns `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 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.
*/
getAttributes() {
return this._attrs.entries();
}
/**
* Returns iterator that iterates over this node's attribute keys.
*/
getAttributeKeys() {
return this._attrs.keys();
}
/**
* Converts `Node` to plain object and returns it.
*
* @returns `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.
*
* @internal
* @returns Node with same attributes as this node.
*/
_clone(_deep) {
return new this.constructor(this._attrs);
}
/**
* Removes this node from its parent.
*
* @internal
* @see module:engine/model/writer~ModelWriter#remove
*/
_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~ModelWriter#setAttribute
* @internal
* @param 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~ModelWriter#setAttributes
* @internal
* @param 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~ModelWriter#removeAttribute
* @internal
* @param key Key of attribute to remove.
* @returns `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~ModelWriter#clearAttributes
* @internal
*/
_clearAttributes() {
this._attrs.clear();
}
}
// The magic of type inference using `is` method is centralized in `TypeCheckable` class.
// Proper overload would interfere with that.
ModelNode.prototype.is = function (type) {
return type === 'node' || type === 'model:node';
};