collection.js 6.8 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 utils from './utils.js';
  9. /**
  10. * Collections are ordered sets of objects. Items in the collection can be retrieved by their indexes
  11. * in the collection (like in an array) or by their ids.
  12. *
  13. * If an object without an `id` property is being added to the collection, the `id` property will be generated
  14. * automatically. Note that the automatically generated id is unique only within this single collection instance.
  15. *
  16. * By default an item in the collection is identified by its `id` property. The name of the identifier can be
  17. * configured through the constructor of the collection.
  18. *
  19. * @class Collection
  20. * @mixins EventEmitter
  21. */
  22. export default class Collection {
  23. /**
  24. * Creates a new Collection instance.
  25. *
  26. * @constructor
  27. * @param {Iterale} [items] Items to be added to the collection.
  28. * @param {Object} options The options object.
  29. * @param {String} [options.idProperty='id'] The name of the property which is considered to identify an item.
  30. */
  31. constructor( options ) {
  32. /**
  33. * The internal list of items in the collection.
  34. *
  35. * @private
  36. * @property {Object[]}
  37. */
  38. this._items = [];
  39. /**
  40. * The internal map of items in the collection.
  41. *
  42. * @private
  43. * @property {Map}
  44. */
  45. this._itemMap = new Map();
  46. /**
  47. * The name of the property which is considered to identify an item.
  48. *
  49. * @private
  50. * @property {String}
  51. */
  52. this._idProperty = options && options.idProperty || 'id';
  53. }
  54. /**
  55. * The number of items available in the collection.
  56. *
  57. * @property length
  58. */
  59. get length() {
  60. return this._items.length;
  61. }
  62. /**
  63. * Adds an item into the collection.
  64. *
  65. * If the item does not have an id, then it will be automatically generated and set on the item.
  66. *
  67. * @chainable
  68. * @param {Object} item
  69. * @param {Number} [index] The position of the item in the collection. The item
  70. * is pushed to the collection when `index` not specified.
  71. */
  72. add( item, index ) {
  73. let itemId;
  74. const idProperty = this._idProperty;
  75. if ( ( idProperty in item ) ) {
  76. itemId = item[ idProperty ];
  77. if ( typeof itemId != 'string' ) {
  78. /**
  79. * This item's id should be a string.
  80. *
  81. * @error collection-add-invalid-id
  82. */
  83. throw new CKEditorError( 'collection-add-invalid-id' );
  84. }
  85. if ( this.get( itemId ) ) {
  86. /**
  87. * This item already exists in the collection.
  88. *
  89. * @error collection-add-item-already-exists
  90. */
  91. throw new CKEditorError( 'collection-add-item-already-exists' );
  92. }
  93. } else {
  94. itemId = this._getNextId();
  95. item[ idProperty ] = itemId;
  96. }
  97. // TODO: Use ES6 default function argument.
  98. if ( index === undefined ) {
  99. index = this._items.length;
  100. } else if ( index > this._items.length || index < 0 ) {
  101. /**
  102. * The index number has invalid value.
  103. *
  104. * @error collection-add-item-bad-index
  105. */
  106. throw new CKEditorError( 'collection-add-item-invalid-index' );
  107. }
  108. this._items.splice( index, 0, item );
  109. this._itemMap.set( itemId, item );
  110. this.fire( 'add', item, index );
  111. return this;
  112. }
  113. /**
  114. * Gets item by its id or index.
  115. *
  116. * @param {String|Number} idOrIndex The item id or index in the collection.
  117. * @returns {Object} The requested item or `null` if such item does not exist.
  118. */
  119. get( idOrIndex ) {
  120. let item;
  121. if ( typeof idOrIndex == 'string' ) {
  122. item = this._itemMap.get( idOrIndex );
  123. } else if ( typeof idOrIndex == 'number' ) {
  124. item = this._items[ idOrIndex ];
  125. } else {
  126. /**
  127. * Index or id must be given.
  128. *
  129. * @error collection-get-invalid-arg
  130. */
  131. throw new CKEditorError( 'collection-get-invalid-arg: Index or id must be given.' );
  132. }
  133. return item || null;
  134. }
  135. /**
  136. * Removes an item from the collection.
  137. *
  138. * @param {Object|Number|String} subject The item to remove, its id or index in the collection.
  139. * @returns {Object} The removed item.
  140. */
  141. remove( subject ) {
  142. let index, id, item;
  143. let itemDoesNotExist = false;
  144. const idProperty = this._idProperty;
  145. if ( typeof subject == 'string' ) {
  146. id = subject;
  147. item = this._itemMap.get( id );
  148. itemDoesNotExist = !item;
  149. if ( item ) {
  150. index = this._items.indexOf( item );
  151. }
  152. } else if ( typeof subject == 'number' ) {
  153. index = subject;
  154. item = this._items[ index ];
  155. itemDoesNotExist = !item;
  156. if ( item ) {
  157. id = item[ idProperty ];
  158. }
  159. } else {
  160. item = subject;
  161. id = item[ idProperty ];
  162. index = this._items.indexOf( item );
  163. itemDoesNotExist = ( index == -1 || !this._itemMap.get( id ) );
  164. }
  165. if ( itemDoesNotExist ) {
  166. /**
  167. * Item not found.
  168. *
  169. * @error collection-remove-404
  170. */
  171. throw new CKEditorError( 'collection-remove-404: Item not found.' );
  172. }
  173. this._items.splice( index, 1 );
  174. this._itemMap.delete( id );
  175. this.fire( 'remove', item );
  176. return item;
  177. }
  178. /**
  179. * Executes the callback for each item in the collection and composes an array or values returned by this callback.
  180. *
  181. * @param {Function} callback
  182. * @param {Item} callback.item
  183. * @param {Number} callback.index
  184. * @params {Object} ctx Context in which the `callback` will be called.
  185. * @returns {Array} The result of mapping.
  186. */
  187. map( callback, ctx ) {
  188. return this._items.map( callback, ctx );
  189. }
  190. /**
  191. * Finds the first item in the collection for which the `callback` returns a true value.
  192. *
  193. * @param {Function} callback
  194. * @param {Object} callback.item
  195. * @param {Number} callback.index
  196. * @returns {Object} The item for which `callback` returned a true value.
  197. * @params {Object} ctx Context in which the `callback` will be called.
  198. */
  199. find( callback, ctx ) {
  200. return this._items.find( callback, ctx );
  201. }
  202. /**
  203. * Returns an array with items for which the `callback` returned a true value.
  204. *
  205. * @param {Function} callback
  206. * @param {Object} callback.item
  207. * @param {Number} callback.index
  208. * @params {Object} ctx Context in which the `callback` will be called.
  209. * @returns {Object[]} The array with matching items.
  210. */
  211. filter( callback, ctx ) {
  212. return this._items.filter( callback, ctx );
  213. }
  214. /**
  215. * Collection iterator.
  216. */
  217. [ Symbol.iterator ]() {
  218. return this._items[ Symbol.iterator ]();
  219. }
  220. /**
  221. * Generates next (not yet used) id for unidentified item being add to the collection.
  222. *
  223. * @returns {String} The next id.
  224. */
  225. _getNextId() {
  226. let id;
  227. do {
  228. id = String( utils.uid() );
  229. } while ( this._itemMap.has( id ) );
  230. return id;
  231. }
  232. }
  233. utils.mix( Collection, EmitterMixin );
  234. /**
  235. * Fired when an item is added to the collection.
  236. *
  237. * @event add
  238. * @param {Object} item The added item.
  239. */
  240. /**
  241. * Fired when an item is removed from the collection.
  242. *
  243. * @event remove
  244. * @param {Object} item The removed item.
  245. */