collection.js 6.9 KB

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  1. /**
  2. * @license Copyright (c) 2003-2016, CKSource - Frederico Knabben. All rights reserved.
  3. * For licensing, see LICENSE.md.
  4. */
  5. 'use strict';
  6. import EmitterMixin from './emittermixin.js';
  7. import CKEditorError from './ckeditorerror.js';
  8. import utilsObject from './lib/lodash/object.js';
  9. import utils from './utils.js';
  10. /**
  11. * Collections are ordered sets of objects. Items in the collection can be retrieved by their indexes
  12. * in the collection (like in an array) or by their ids.
  13. *
  14. * If an object without an `id` property is being added to the collection, the `id` property will be generated
  15. * automatically. Note that the automatically generated id is unique only within this single collection instance.
  16. *
  17. * By default an item in the collection is identified by its `id` property. The name of the identifier can be
  18. * configured through the constructor of the collection.
  19. *
  20. * @class Collection
  21. * @mixins EventEmitter
  22. */
  23. export default class Collection {
  24. /**
  25. * Creates a new Collection instance.
  26. *
  27. * @constructor
  28. * @param {Iterale} [items] Items to be added to the collection.
  29. * @param {Object} options The options object.
  30. * @param {String} [options.idProperty='id'] The name of the property which is considered to identify an item.
  31. */
  32. constructor( options ) {
  33. /**
  34. * The internal list of items in the collection.
  35. *
  36. * @private
  37. * @property {Object[]}
  38. */
  39. this._items = [];
  40. /**
  41. * The internal map of items in the collection.
  42. *
  43. * @private
  44. * @property {Map}
  45. */
  46. this._itemMap = new Map();
  47. /**
  48. * The name of the property which is considered to identify an item.
  49. *
  50. * @private
  51. * @property {String}
  52. */
  53. this._idProperty = options && options.idProperty || 'id';
  54. }
  55. /**
  56. * The number of items available in the collection.
  57. *
  58. * @property length
  59. */
  60. get length() {
  61. return this._items.length;
  62. }
  63. /**
  64. * Adds an item into the collection.
  65. *
  66. * If the item does not have an id, then it will be automatically generated and set on the item.
  67. *
  68. * @chainable
  69. * @param {Object} item
  70. * @param {Number} [index] The position of the item in the collection. The item
  71. * is pushed to the collection when `index` not specified.
  72. */
  73. add( item, index ) {
  74. let itemId;
  75. const idProperty = this._idProperty;
  76. if ( ( idProperty in item ) ) {
  77. itemId = item[ idProperty ];
  78. if ( typeof itemId != 'string' ) {
  79. /**
  80. * This item's id should be a string.
  81. *
  82. * @error collection-add-invalid-id
  83. */
  84. throw new CKEditorError( 'collection-add-invalid-id' );
  85. }
  86. if ( this.get( itemId ) ) {
  87. /**
  88. * This item already exists in the collection.
  89. *
  90. * @error collection-add-item-already-exists
  91. */
  92. throw new CKEditorError( 'collection-add-item-already-exists' );
  93. }
  94. } else {
  95. itemId = this._getNextId();
  96. item[ idProperty ] = itemId;
  97. }
  98. // TODO: Use ES6 default function argument.
  99. if ( index === undefined ) {
  100. index = this._items.length;
  101. } else if ( index > this._items.length || index < 0 ) {
  102. /**
  103. * The index number has invalid value.
  104. *
  105. * @error collection-add-item-bad-index
  106. */
  107. throw new CKEditorError( 'collection-add-item-invalid-index' );
  108. }
  109. this._items.splice( index, 0, item );
  110. this._itemMap.set( itemId, item );
  111. this.fire( 'add', item, index );
  112. return this;
  113. }
  114. /**
  115. * Gets item by its id or index.
  116. *
  117. * @param {String|Number} idOrIndex The item id or index in the collection.
  118. * @returns {Object} The requested item or `null` if such item does not exist.
  119. */
  120. get( idOrIndex ) {
  121. let item;
  122. if ( typeof idOrIndex == 'string' ) {
  123. item = this._itemMap.get( idOrIndex );
  124. } else if ( typeof idOrIndex == 'number' ) {
  125. item = this._items[ idOrIndex ];
  126. } else {
  127. /**
  128. * Index or id must be given.
  129. *
  130. * @error collection-get-invalid-arg
  131. */
  132. throw new CKEditorError( 'collection-get-invalid-arg: Index or id must be given.' );
  133. }
  134. return item || null;
  135. }
  136. /**
  137. * Removes an item from the collection.
  138. *
  139. * @param {Object|Number|String} subject The item to remove, its id or index in the collection.
  140. * @returns {Object} The removed item.
  141. */
  142. remove( subject ) {
  143. let index, id, item;
  144. let itemDoesNotExist = false;
  145. const idProperty = this._idProperty;
  146. if ( typeof subject == 'string' ) {
  147. id = subject;
  148. item = this._itemMap.get( id );
  149. itemDoesNotExist = !item;
  150. if ( item ) {
  151. index = this._items.indexOf( item );
  152. }
  153. } else if ( typeof subject == 'number' ) {
  154. index = subject;
  155. item = this._items[ index ];
  156. itemDoesNotExist = !item;
  157. if ( item ) {
  158. id = item[ idProperty ];
  159. }
  160. } else {
  161. item = subject;
  162. id = item[ idProperty ];
  163. index = this._items.indexOf( item );
  164. itemDoesNotExist = ( index == -1 || !this._itemMap.get( id ) );
  165. }
  166. if ( itemDoesNotExist ) {
  167. /**
  168. * Item not found.
  169. *
  170. * @error collection-remove-404
  171. */
  172. throw new CKEditorError( 'collection-remove-404: Item not found.' );
  173. }
  174. this._items.splice( index, 1 );
  175. this._itemMap.delete( id );
  176. this.fire( 'remove', item );
  177. return item;
  178. }
  179. /**
  180. * Executes the callback for each item in the collection and composes an array or values returned by this callback.
  181. *
  182. * @param {Function} callback
  183. * @param {Item} callback.item
  184. * @param {Number} callback.index
  185. * @params {Object} ctx Context in which the `callback` will be called.
  186. * @returns {Array} The result of mapping.
  187. */
  188. map( callback, ctx ) {
  189. return this._items.map( callback, ctx );
  190. }
  191. /**
  192. * Finds the first item in the collection for which the `callback` returns a true value.
  193. *
  194. * @param {Function} callback
  195. * @param {Object} callback.item
  196. * @param {Number} callback.index
  197. * @returns {Object} The item for which `callback` returned a true value.
  198. * @params {Object} ctx Context in which the `callback` will be called.
  199. */
  200. find( callback, ctx ) {
  201. return this._items.find( callback, ctx );
  202. }
  203. /**
  204. * Returns an array with items for which the `callback` returned a true value.
  205. *
  206. * @param {Function} callback
  207. * @param {Object} callback.item
  208. * @param {Number} callback.index
  209. * @params {Object} ctx Context in which the `callback` will be called.
  210. * @returns {Object[]} The array with matching items.
  211. */
  212. filter( callback, ctx ) {
  213. return this._items.filter( callback, ctx );
  214. }
  215. /**
  216. * Collection iterator.
  217. */
  218. [ Symbol.iterator ]() {
  219. return this._items[ Symbol.iterator ]();
  220. }
  221. /**
  222. * Generates next (not yet used) id for unidentified item being add to the collection.
  223. *
  224. * @returns {String} The next id.
  225. */
  226. _getNextId() {
  227. let id;
  228. do {
  229. id = String( utils.uid() );
  230. } while ( this._itemMap.has( id ) );
  231. return id;
  232. }
  233. }
  234. utilsObject.extend( Collection.prototype, EmitterMixin );
  235. /**
  236. * Fired when an item is added to the collection.
  237. *
  238. * @event add
  239. * @param {Object} item The added item.
  240. */
  241. /**
  242. * Fired when an item is removed from the collection.
  243. *
  244. * @event remove
  245. * @param {Object} item The removed item.
  246. */