public function get($js = null, $compress = true)
    {
        if (null === $js) {
            foreach ((array) $this->_list as $src) {
                if (!file_exists($src)) {
                    continue;
                }

                $js .= file_get_contents($src);
            }
        }

        $this->_list = [];

        return $compress ? $this->parse($js) : $js;
    }