liveposition.js 5.4 KB

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  1. /**
  2. * @license Copyright (c) 2003-2019, 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 liveposition-root-not-rootelement
  43. */
  44. throw new CKEditorError(
  45. 'model-liveposition-root-not-rootelement: LivePosition\'s root has to be an instance of RootElement.',
  46. root
  47. );
  48. }
  49. bindWithDocument.call( this );
  50. }
  51. /**
  52. * Unbinds all events previously bound by `LivePosition`. Use it whenever you don't need `LivePosition` instance
  53. * anymore (i.e. when leaving scope in which it was declared or before re-assigning variable that was
  54. * referring to it).
  55. */
  56. detach() {
  57. this.stopListening();
  58. }
  59. /**
  60. * Creates a {@link module:engine/model/position~Position position instance}, which is equal to this live position.
  61. *
  62. * @returns {module:engine/model/position~Position}
  63. */
  64. toPosition() {
  65. return new Position( this.root, this.path.slice(), this.stickiness );
  66. }
  67. /**
  68. * Creates a `LivePosition` instance that is equal to position.
  69. *
  70. * @param {module:engine/model/position~Position} position
  71. * @param {module:engine/model/position~PositionStickiness} [stickiness]
  72. * @returns {module:engine/model/position~Position}
  73. */
  74. static fromPosition( position, stickiness ) {
  75. return new this( position.root, position.path.slice(), stickiness ? stickiness : position.stickiness );
  76. }
  77. /**
  78. * @static
  79. * @protected
  80. * @method module:engine/model/liveposition~LivePosition._createAfter
  81. * @see module:engine/model/position~Position._createAfter
  82. * @param {module:engine/model/node~Node} node
  83. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone']
  84. * @returns {module:engine/model/liveposition~LivePosition}
  85. */
  86. /**
  87. * @static
  88. * @protected
  89. * @method module:engine/model/liveposition~LivePosition._createBefore
  90. * @see module:engine/model/position~Position._createBefore
  91. * @param {module:engine/model/node~Node} node
  92. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone']
  93. * @returns {module:engine/model/liveposition~LivePosition}
  94. */
  95. /**
  96. * @static
  97. * @protected
  98. * @method module:engine/model/liveposition~LivePosition._createAt
  99. * @see module:engine/model/position~Position._createAt
  100. * @param {module:engine/model/item~Item|module:engine/model/position~Position} itemOrPosition
  101. * @param {Number|'end'|'before'|'after'} [offset]
  102. * @param {module:engine/model/position~PositionStickiness} [stickiness='toNone']
  103. * @returns {module:engine/model/liveposition~LivePosition}
  104. */
  105. /**
  106. * Fired when `LivePosition` instance is changed due to changes on {@link module:engine/model/document~Document}.
  107. *
  108. * @event module:engine/model/liveposition~LivePosition#change
  109. * @param {module:engine/model/position~Position} oldPosition Position equal to this live position before it got changed.
  110. */
  111. }
  112. // Binds this `LivePosition` to the {@link module:engine/model/document~Document document} that owns
  113. // this position's {@link module:engine/model/position~Position#root root}.
  114. //
  115. // @private
  116. function bindWithDocument() {
  117. this.listenTo(
  118. this.root.document.model,
  119. 'applyOperation',
  120. ( event, args ) => {
  121. const operation = args[ 0 ];
  122. if ( !operation.isDocumentOperation ) {
  123. return;
  124. }
  125. transform.call( this, operation );
  126. },
  127. { priority: 'low' }
  128. );
  129. }
  130. // Updates this position accordingly to the updates applied to the model. Bases on change events.
  131. //
  132. // @private
  133. // @param {module:engine/model/operation/operation~Operation} operation Executed operation.
  134. function transform( operation ) {
  135. const result = this.getTransformedByOperation( operation );
  136. if ( !this.isEqual( result ) ) {
  137. const oldPosition = this.toPosition();
  138. this.path = result.path;
  139. this.root = result.root;
  140. this.fire( 'change', oldPosition );
  141. }
  142. }
  143. mix( LivePosition, EmitterMixin );