1  var baseOrderBy = require('./_baseOrderBy'),
 2      isArray = require('./isArray');
 3  
 4  /**
 5   * This method is like `_.sortBy` except that it allows specifying the sort
 6   * orders of the iteratees to sort by. If `orders` is unspecified, all values
 7   * are sorted in ascending order. Otherwise, specify an order of "desc" for
 8   * descending or "asc" for ascending sort order of corresponding values.
 9   *
10   * @static
11   * @memberOf _
12   * @since 4.0.0
13   * @category Collection
14   * @param {Array|Object} collection The collection to iterate over.
15   * @param {Array[]|Function[]|Object[]|string[]} [iteratees=[_.identity]]
16   *  The iteratees to sort by.
17   * @param {string[]} [orders] The sort orders of `iteratees`.
18   * @param- {Object} [guard] Enables use as an iteratee for methods like `_.reduce`.
19   * @returns {Array} Returns the new sorted array.
20   * @example
21   *
22   * var users = [
23   *   { 'user': 'fred',   'age': 48 },
24   *   { 'user': 'barney', 'age': 34 },
25   *   { 'user': 'fred',   'age': 40 },
26   *   { 'user': 'barney', 'age': 36 }
27   * ];
28   *
29   * // Sort by `user` in ascending order and by `age` in descending order.
30   * _.orderBy(users, ['user', 'age'], ['asc', 'desc']);
31   * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 40]]
32   */
33  function orderBy(collection, iteratees, orders, guard) {
34    if (collection == null) {
35      return [];
36    }
37    if (!isArray(iteratees)) {
38      iteratees = iteratees == null ? [] : [iteratees];
39    }
40    orders = guard ? undefined : orders;
41    if (!isArray(orders)) {
42      orders = orders == null ? [] : [orders];
43    }
44    return baseOrderBy(collection, iteratees, orders);
45  }
46  
47  module.exports = orderBy;