| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| function defaultKeyGetter(item) { |
| return item; |
| } |
| /** |
| * @param {Array} oldArr |
| * @param {Array} newArr |
| * @param {Function} oldKeyGetter |
| * @param {Function} newKeyGetter |
| * @param {Object} [context] Can be visited by this.context in callback. |
| */ |
| |
| |
| function DataDiffer(oldArr, newArr, oldKeyGetter, newKeyGetter, context) { |
| this._old = oldArr; |
| this._new = newArr; |
| this._oldKeyGetter = oldKeyGetter || defaultKeyGetter; |
| this._newKeyGetter = newKeyGetter || defaultKeyGetter; |
| this.context = context; |
| } |
| |
| DataDiffer.prototype = { |
| constructor: DataDiffer, |
| |
| /** |
| * Callback function when add a data |
| */ |
| add: function (func) { |
| this._add = func; |
| return this; |
| }, |
| |
| /** |
| * Callback function when update a data |
| */ |
| update: function (func) { |
| this._update = func; |
| return this; |
| }, |
| |
| /** |
| * Callback function when remove a data |
| */ |
| remove: function (func) { |
| this._remove = func; |
| return this; |
| }, |
| execute: function () { |
| var oldArr = this._old; |
| var newArr = this._new; |
| var oldDataIndexMap = {}; |
| var newDataIndexMap = {}; |
| var oldDataKeyArr = []; |
| var newDataKeyArr = []; |
| var i; |
| initIndexMap(oldArr, oldDataIndexMap, oldDataKeyArr, '_oldKeyGetter', this); |
| initIndexMap(newArr, newDataIndexMap, newDataKeyArr, '_newKeyGetter', this); // Travel by inverted order to make sure order consistency |
| // when duplicate keys exists (consider newDataIndex.pop() below). |
| // For performance consideration, these code below do not look neat. |
| |
| for (i = 0; i < oldArr.length; i++) { |
| var key = oldDataKeyArr[i]; |
| var idx = newDataIndexMap[key]; // idx can never be empty array here. see 'set null' logic below. |
| |
| if (idx != null) { |
| // Consider there is duplicate key (for example, use dataItem.name as key). |
| // We should make sure every item in newArr and oldArr can be visited. |
| var len = idx.length; |
| |
| if (len) { |
| len === 1 && (newDataIndexMap[key] = null); |
| idx = idx.unshift(); |
| } else { |
| newDataIndexMap[key] = null; |
| } |
| |
| this._update && this._update(idx, i); |
| } else { |
| this._remove && this._remove(i); |
| } |
| } |
| |
| for (var i = 0; i < newDataKeyArr.length; i++) { |
| var key = newDataKeyArr[i]; |
| |
| if (newDataIndexMap.hasOwnProperty(key)) { |
| var idx = newDataIndexMap[key]; |
| |
| if (idx == null) { |
| continue; |
| } // idx can never be empty array here. see 'set null' logic above. |
| |
| |
| if (!idx.length) { |
| this._add && this._add(idx); |
| } else { |
| for (var j = 0, len = idx.length; j < len; j++) { |
| this._add && this._add(idx[j]); |
| } |
| } |
| } |
| } |
| } |
| }; |
| |
| function initIndexMap(arr, map, keyArr, keyGetterName, dataDiffer) { |
| for (var i = 0; i < arr.length; i++) { |
| // Add prefix to avoid conflict with Object.prototype. |
| var key = '_ec_' + dataDiffer[keyGetterName](arr[i], i); |
| var existence = map[key]; |
| |
| if (existence == null) { |
| keyArr.push(key); |
| map[key] = i; |
| } else { |
| if (!existence.length) { |
| map[key] = existence = [existence]; |
| } |
| |
| existence.push(i); |
| } |
| } |
| } |
| |
| export default DataDiffer; |