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/**
* 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;