lodash/collection/sortBy.js

define(['../internal/baseCallback', '../internal/baseEach', '../internal/baseSortBy', '../internal/compareAscending', '../internal/isIterateeCall', '../internal/isLength'], function(baseCallback, baseEach, baseSortBy, compareAscending, isIterateeCall, isLength) {

  /**
   * Creates an array of elements, sorted in ascending order by the results of
   * running each element in a collection through `iteratee`. This method performs
   * a stable sort, that is, it preserves the original sort order of equal elements.
   * The `iteratee` is bound to `thisArg` and invoked with three arguments;
   * (value, index|key, collection).
   *
   * If a property name is provided for `predicate` the created `_.property`
   * style callback returns the property value of the given element.
   *
   * If a value is also provided for `thisArg` the created `_.matchesProperty`
   * style callback returns `true` for elements that have a matching property
   * value, else `false`.
   *
   * If an object is provided for `predicate` the created `_.matches` style
   * callback returns `true` for elements that have the properties of the given
   * object, else `false`.
   *
   * @static
   * @memberOf _
   * @category Collection
   * @param {Array|Object|string} collection The collection to iterate over.
   * @param {Array|Function|Object|string} [iteratee=_.identity] The function
   *  invoked per iteration. If a property name or an object is provided it is
   *  used to create a `_.property` or `_.matches` style callback respectively.
   * @param {*} [thisArg] The `this` binding of `iteratee`.
   * @returns {Array} Returns the new sorted array.
   * @example
   *
   * _.sortBy([1, 2, 3], function(n) {
   *   return Math.sin(n);
   * });
   * // => [3, 1, 2]
   *
   * _.sortBy([1, 2, 3], function(n) {
   *   return this.sin(n);
   * }, Math);
   * // => [3, 1, 2]
   *
   * var users = [
   *   { 'user': 'fred' },
   *   { 'user': 'pebbles' },
   *   { 'user': 'barney' }
   * ];
   *
   * // using the `_.property` callback shorthand
   * _.pluck(_.sortBy(users, 'user'), 'user');
   * // => ['barney', 'fred', 'pebbles']
   */
  function sortBy(collection, iteratee, thisArg) {
    var index = -1,
        length = collection ? collection.length : 0,
        result = isLength(length) ? Array(length) : [];

    if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
      iteratee = null;
    }
    iteratee = baseCallback(iteratee, thisArg, 3);
    baseEach(collection, function(value, key, collection) {
      result[++index] = { 'criteria': iteratee(value, key, collection), 'index': index, 'value': value };
    });
    return baseSortBy(result, compareAscending);
  }

  return sortBy;
});