| /** |
| * Lo-Dash 2.4.1 (Custom Build) <http://lodash.com/> |
| * Build: `lodash modularize modern exports="node" -o ./modern/` |
| * Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/> |
| * Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE> |
| * Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors |
| * Available under MIT license <http://lodash.com/license> |
| */ |
| var createCallback = require('../functions/createCallback'), |
| forOwn = require('../objects/forOwn'); |
| |
| /** |
| * Creates an array of values by running each element in the collection |
| * through the callback. The callback is bound to `thisArg` and invoked with |
| * three arguments; (value, index|key, collection). |
| * |
| * If a property name is provided for `callback` the created "_.pluck" style |
| * callback will return the property value of the given element. |
| * |
| * If an object is provided for `callback` the created "_.where" style callback |
| * will return `true` for elements that have the properties of the given object, |
| * else `false`. |
| * |
| * @static |
| * @memberOf _ |
| * @alias collect |
| * @category Collections |
| * @param {Array|Object|string} collection The collection to iterate over. |
| * @param {Function|Object|string} [callback=identity] The function called |
| * per iteration. If a property name or object is provided it will be used |
| * to create a "_.pluck" or "_.where" style callback, respectively. |
| * @param {*} [thisArg] The `this` binding of `callback`. |
| * @returns {Array} Returns a new array of the results of each `callback` execution. |
| * @example |
| * |
| * _.map([1, 2, 3], function(num) { return num * 3; }); |
| * // => [3, 6, 9] |
| * |
| * _.map({ 'one': 1, 'two': 2, 'three': 3 }, function(num) { return num * 3; }); |
| * // => [3, 6, 9] (property order is not guaranteed across environments) |
| * |
| * var characters = [ |
| * { 'name': 'barney', 'age': 36 }, |
| * { 'name': 'fred', 'age': 40 } |
| * ]; |
| * |
| * // using "_.pluck" callback shorthand |
| * _.map(characters, 'name'); |
| * // => ['barney', 'fred'] |
| */ |
| function map(collection, callback, thisArg) { |
| var index = -1, |
| length = collection ? collection.length : 0; |
| |
| callback = createCallback(callback, thisArg, 3); |
| if (typeof length == 'number') { |
| var result = Array(length); |
| while (++index < length) { |
| result[index] = callback(collection[index], index, collection); |
| } |
| } else { |
| result = []; |
| forOwn(collection, function(value, key, collection) { |
| result[++index] = callback(value, key, collection); |
| }); |
| } |
| return result; |
| } |
| |
| module.exports = map; |