@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
*/
/**
* @module engine/model/textproxy
*/
import { ModelTypeCheckable } from './typecheckable.js';
import { CKEditorError } from '@ckeditor/ckeditor5-utils';
// @if CK_DEBUG_ENGINE // const { convertMapToStringifiedObject } = require( '../dev-utils/utils' );
/**
* `ModelTextProxy` represents a part of {@link module:engine/model/text~ModelText text node}.
*
* Since {@link module:engine/model/position~ModelPosition positions} can be placed between characters of a text node,
* {@link module:engine/model/range~ModelRange ranges} may contain only parts of text nodes.
* When {@link module:engine/model/range~ModelRange#getItems getting items}
* contained in such range, we need to represent a part of that text node, since returning the whole text node would be incorrect.
* `ModelTextProxy` solves this issue.
*
* `ModelTextProxy` has an API similar to {@link module:engine/model/text~ModelText Text} and allows to do
* most of the common tasks performed on model nodes.
*
* **Note:** Some `ModelTextProxy` instances may represent whole text node, not just a part of it.
* See {@link module:engine/model/textproxy~ModelTextProxy#isPartial}.
*
* **Note:** `ModelTextProxy` is not an instance of {@link module:engine/model/node~ModelNode node}. Keep this in mind when using it as a
* parameter of methods.
*
* **Note:** `ModelTextProxy` is a readonly interface. If you want to perform changes on model data represented by a `ModelTextProxy`
* use {@link module:engine/model/writer~ModelWriter model writer API}.
*
* **Note:** `ModelTextProxy` instances are created on the fly, basing on the current state of model. Because of this, it is
* highly unrecommended to store references to `ModelTextProxy` instances. `ModelTextProxy` instances are not refreshed when
* model changes, so they might get invalidated. Instead, consider creating {@link module:engine/model/liveposition~ModelLivePosition live
* position}.
*
* `ModelTextProxy` instances are created by {@link module:engine/model/treewalker~ModelTreeWalker model tree walker}.
* You should not need to create an instance of this class by your own.
*/
export class ModelTextProxy extends ModelTypeCheckable {
/**
* Text node which part is represented by this text proxy.
*/
textNode;
/**
* Text data represented by this text proxy.
*/
data;
/**
* Offset in {@link module:engine/model/textproxy~ModelTextProxy#textNode text node} from which the text proxy starts.
*/
offsetInText;
/**
* Creates a text proxy.
*
* @internal
* @param textNode Text node which part is represented by this text proxy.
* @param offsetInText Offset in {@link module:engine/model/textproxy~ModelTextProxy#textNode text node} from which the text proxy
* starts.
* @param length Text proxy length, that is how many text node's characters, starting from `offsetInText` it represents.
*/
constructor(textNode, offsetInText, length) {
super();
this.textNode = textNode;
if (offsetInText < 0 || offsetInText > textNode.offsetSize) {
/**
* Given `offsetInText` value is incorrect.
*
* @error model-textproxy-wrong-offsetintext
*/
throw new CKEditorError('model-textproxy-wrong-offsetintext', this);
}
if (length < 0 || offsetInText + length > textNode.offsetSize) {
/**
* Given `length` value is incorrect.
*
* @error model-textproxy-wrong-length
*/
throw new CKEditorError('model-textproxy-wrong-length', this);
}
this.data = textNode.data.substring(offsetInText, offsetInText + length);
this.offsetInText = offsetInText;
}
/**
* Offset at which this text proxy starts in it's parent.
*
* @see module:engine/model/node~ModelNode#startOffset
*/
get startOffset() {
return this.textNode.startOffset !== null ? this.textNode.startOffset + this.offsetInText : null;
}
/**
* Offset size of this text proxy. Equal to the number of characters represented by the text proxy.
*
* @see module:engine/model/node~ModelNode#offsetSize
*/
get offsetSize() {
return this.data.length;
}
/**
* Offset at which this text proxy ends in it's parent.
*
* @see module:engine/model/node~ModelNode#endOffset
*/
get endOffset() {
return this.startOffset !== null ? this.startOffset + this.offsetSize : null;
}
/**
* Flag indicating whether `ModelTextProxy` instance covers only part of the original
* {@link module:engine/model/text~ModelText text node} (`true`) or the whole text node (`false`).
*
* This is `false` when text proxy starts at the very beginning of
* {@link module:engine/model/textproxy~ModelTextProxy#textNode textNode}
* ({@link module:engine/model/textproxy~ModelTextProxy#offsetInText offsetInText} equals `0`) and text proxy sizes is equal to
* text node size.
*/
get isPartial() {
return this.offsetSize !== this.textNode.offsetSize;
}
/**
* Parent of this text proxy, which is same as parent of text node represented by this text proxy.
*/
get parent() {
return this.textNode.parent;
}
/**
* Root of this text proxy, which is same as root of text node represented by this text proxy.
*/
get root() {
return this.textNode.root;
}
/**
* Gets path to this text proxy.
*
* @see module:engine/model/node~ModelNode#getPath
*/
getPath() {
const path = this.textNode.getPath();
if (path.length > 0) {
path[path.length - 1] += this.offsetInText;
}
return path;
}
/**
* Returns ancestors array of this text proxy.
*
* @param options Options object.
* @param options.includeSelf When set to `true` this text proxy will be also included in parent's array.
* @param options.parentFirst When set to `true`, array will be sorted from text proxy 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;
}
/**
* Checks if this text proxy has an attribute for given key.
*
* @param key Key of attribute to check.
* @returns `true` if attribute with given key is set on text proxy, `false` otherwise.
*/
hasAttribute(key) {
return this.textNode.hasAttribute(key);
}
/**
* Gets an attribute value for given key or `undefined` if that attribute is not set on text proxy.
*
* @param key Key of attribute to look for.
* @returns Attribute value or `undefined`.
*/
getAttribute(key) {
return this.textNode.getAttribute(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.textNode.getAttributes();
}
/**
* Returns iterator that iterates over this node's attribute keys.
*/
getAttributeKeys() {
return this.textNode.getAttributeKeys();
}
}
// The magic of type inference using `is` method is centralized in `TypeCheckable` class.
// Proper overload would interfere with that.
ModelTextProxy.prototype.is = function (type) {
return type === '$textProxy' || type === 'model:$textProxy' ||
// This are legacy values kept for backward compatibility.
type === 'textProxy' || type === 'model:textProxy';
};