src/FrontendAsset.php
public function add($file, $params = 'footer', $onUnknownExtension = false)
    {
        RoumenAsset::add($this->elixir($file), $params, $onUnknownExtension);
    }
public function add($file, $params = 'footer', $onUnknownExtension = false)
    {
        RoumenAsset::add($this->elixir($file), $params, $onUnknownExtension);
    }
Add the asset using our version of the exlixer loader.

@param string $file
@param string $params
@param bool   $onUnknownExtension

@return void