code: public function addJS($js)
      {
          if (is_array($js)) {
              foreach ($js as $key => $value) {
                  $this->js[] = new FileAsset($js);
              }
              return $this;
          } else {
              throw new InternalException("JS files to add is not an array");
          }
      }
docs: /*
  Public: Add js files
  
  $js - array of js files to load
  
  Returns js array