public function getCachedAssets($key) {
    $files = array();

    $js = "/cachedassets/{$key}.js";
    if (file_exists($this->path . $js)) {
      $files['scripts'] = array((object) array(
        'path' => $js,
        'version' => ''
      ));
    }

    $css = "/cachedassets/{$key}.css";
    if (file_exists($this->path . $css)) {
      $files['styles'] = array((object) array(
        'path' => $css,
        'version' => ''
      ));
    }

    return empty($files) ? NULL : $files;
  }