function arrayPush(array, values) {
  var index = -1,
      length = values.length,
      offset = array.length;

  while (++index < length) {
    array[offset + index] = values[index];
  }
  return array;
}
Appends the elements of `values` to `array`.

@private
@param {Array} array The array to modify.
@param {Array} values The values to append.
@returns {Array} Returns `array`.