liveposition.js 6.1 KB

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  1. /**
  2. * @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved.
  3. * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
  4. */
  5. /**
  6. * @module engine/model/liveposition
  7. */
  8. import Position from './position';
  9. import EmitterMixin from '@ckeditor/ckeditor5-utils/src/emittermixin';
  10. import mix from '@ckeditor/ckeditor5-utils/src/mix';
  11. import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';
  12. /**
  13. * `LivePosition` is a type of {@link module:engine/model/position~Position Position}
  14. * that updates itself as {@link module:engine/model/document~Document document}
  15. * is changed through operations. It may be used as a bookmark.
  16. *
  17. * **Note:** Contrary to {@link module:engine/model/position~Position}, `LivePosition` works only in roots that are
  18. * {@link module:engine/model/rootelement~RootElement}.
  19. * If {@link module:engine/model/documentfragment~DocumentFragment} is passed, error will be thrown.
  20. *
  21. * **Note:** Be very careful when dealing with `LivePosition`. Each `LivePosition` instance bind events that might
  22. * have to be unbound.
  23. * Use {@link module:engine/model/liveposition~LivePosition#detach} whenever you don't need `LivePosition` anymore.
  24. *
  25. * @extends module:engine/model/position~Position
  26. */
  27. export default class LivePosition extends Position {
  28. /**
  29. * Creates a live position.
  30. *
  31. * @see module:engine/model/position~Position
  32. * @param {module:engine/model/rootelement~RootElement} root
  33. * @param {Array.<Number>} path
  34. * @param {module:engine/model/position~PositionStickiness} [stickiness]
  35. */
  36. constructor( root, path, stickiness = 'toNone' ) {
  37. super( root, path, stickiness );
  38. if ( !this.root.is( 'rootElement' ) ) {
  39. /**
  40. * LivePosition's root has to be an instance of RootElement.
  41. *
  42. * @error model-liveposition-root-not-rootelement
  43. */
  44. throw new CKEditorError( 'model-liveposition-root-not-rootelement', root );
  45. }
  46. bindWithDocument.call( this );
  47. }
  48. /**
  49. * Unbinds all events previously bound by `LivePosition`. Use it whenever you don't need `LivePosition` instance
  50. * anymore (i.e. when leaving scope in which it was declared or before re-assigning variable that was
  51. * referring to it).
  52. */
  53. detach() {
  54. this.stopListening();
  55. }
  56. /**
  57. * Checks whether this object is of the given.
  58. *
  59. * livePosition.is( 'position' ); // -> true
  60. * livePosition.is( 'model:position' ); // -> true
  61. * livePosition.is( 'liveposition' ); // -> true
  62. * livePosition.is( 'model:livePosition' ); // -> true
  63. *
  64. * livePosition.is( 'view:position' ); // -> false
  65. * livePosition.is( 'documentSelection' ); // -> false
  66. *
  67. * {@link module:engine/model/node~Node#is Check the entire list of model objects} which implement the `is()` method.
  68. *
  69. * @param {String} type
  70. * @returns {Boolean}
  71. */
  72. is( type ) {
  73. return type === 'livePosition' || type === 'model:livePosition' ||
  74. // From super.is(). This is highly utilised method and cannot call super. See ckeditor/ckeditor5#6529.
  75. type == 'position' || type === 'model:position';
  76. }
  77. /**
  78. * Creates a {@link module:engine/model/position~Position position instance}, which is equal to this live position.
  79. *
  80. * @returns {module:engine/model/position~Position}
  81. */
  82. toPosition() {
  83. return new Position( this.root, this.path.slice(), this.stickiness );
  84. }
  85. /**
  86. * Creates a `LivePosition` instance that is equal to position.
  87. *
  88. * @param {module:engine/model/position~Position} position
  89. * @param {module:engine/model/position~PositionStickiness} [stickiness]
  90. * @returns {module:engine/model/position~Position}
  91. */
  92. static fromPosition( position, stickiness ) {
  93. return new this( position.root, position.path.slice(), stickiness ? stickiness : position.stickiness );
  94. }
  95. /**
  96. * @static
  97. * @protected
  98. * @method module:engine/model/liveposition~LivePosition._createAfter
  99. * @see module:engine/model/position~Position._createAfter
  100. * @param {module:engine/model/node~Node} node
  101. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone']
  102. * @returns {module:engine/model/liveposition~LivePosition}
  103. */
  104. /**
  105. * @static
  106. * @protected
  107. * @method module:engine/model/liveposition~LivePosition._createBefore
  108. * @see module:engine/model/position~Position._createBefore
  109. * @param {module:engine/model/node~Node} node
  110. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone']
  111. * @returns {module:engine/model/liveposition~LivePosition}
  112. */
  113. /**
  114. * @static
  115. * @protected
  116. * @method module:engine/model/liveposition~LivePosition._createAt
  117. * @see module:engine/model/position~Position._createAt
  118. * @param {module:engine/model/item~Item|module:engine/model/position~Position} itemOrPosition
  119. * @param {Number|'end'|'before'|'after'} [offset]
  120. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone']
  121. * @returns {module:engine/model/liveposition~LivePosition}
  122. */
  123. /**
  124. * Fired when `LivePosition` instance is changed due to changes on {@link module:engine/model/document~Document}.
  125. *
  126. * @event module:engine/model/liveposition~LivePosition#change
  127. * @param {module:engine/model/position~Position} oldPosition Position equal to this live position before it got changed.
  128. */
  129. }
  130. // Binds this `LivePosition` to the {@link module:engine/model/document~Document document} that owns
  131. // this position's {@link module:engine/model/position~Position#root root}.
  132. //
  133. // @private
  134. function bindWithDocument() {
  135. this.listenTo(
  136. this.root.document.model,
  137. 'applyOperation',
  138. ( event, args ) => {
  139. const operation = args[ 0 ];
  140. if ( !operation.isDocumentOperation ) {
  141. return;
  142. }
  143. transform.call( this, operation );
  144. },
  145. { priority: 'low' }
  146. );
  147. }
  148. // Updates this position accordingly to the updates applied to the model. Bases on change events.
  149. //
  150. // @private
  151. // @param {module:engine/model/operation/operation~Operation} operation Executed operation.
  152. function transform( operation ) {
  153. const result = this.getTransformedByOperation( operation );
  154. if ( !this.isEqual( result ) ) {
  155. const oldPosition = this.toPosition();
  156. this.path = result.path;
  157. this.root = result.root;
  158. this.fire( 'change', oldPosition );
  159. }
  160. }
  161. mix( LivePosition, EmitterMixin );