function baseSortBy(array, comparer) {
  var length = array.length;
  array.sort(comparer);

  while (length--) {
    array[length] = array[length].value;
  }

  return array;
}
The base implementation of `_.sortBy` which uses `comparer` to define the
sort order of `array` and replaces criteria objects with their corresponding
values.

@private
@param {Array} array The array to sort.
@param {Function} comparer The function to define sort order.
@returns {Array} Returns `array`.