/**
 * Lo-Dash 2.4.1 (Custom Build) <http://lodash.com/>
 * Build: `lodash modularize underscore exports="amd" -o ./underscore/`
 * Copyright 2012-2014 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.6.0 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <http://lodash.com/license>
 */
define(['../internals/createAggregator'], function(createAggregator) {

  /** Used for native method references */
  var objectProto = Object.prototype;

  /** Native method shortcuts */
  var hasOwnProperty = objectProto.hasOwnProperty;

  /**
   * Creates an object composed of keys generated from the results of running
   * each element of `collection` through the callback. The corresponding value
   * of each key is the number of times the key was returned by 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 _
   * @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`.
   *
   * _.countBy([4.3, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
   * // => { '4': 1, '6': 2 }
   *
   * _.countBy(['one', 'two', 'three'], 'length');
   * // => { '3': 2, '5': 1 }
   */
  var countBy = createAggregator(function(result, value, key) {
    (hasOwnProperty.call(result, key) ? result[key]++ : result[key] = 1);
  });

  return countBy;
});
   * @returns {Object} Returns the composed aggregate object.
   * @example
   *
   * _.countBy([4.3, 6.1, 6.4], function(num) { return Math.floor(num); });
   * // => { '4': 1, '6': 2 }