src/FrontendAsset.php
public function addAfter($file1, $file2, $params = 'footer', $onUnknownExtension = false)
    {
        RoumenAsset::addAfter($this->elixir($file1), $this->elixir($file2), $params, $onUnknownExtension);
    }
public function addAfter($file1, $file2, $params = 'footer', $onUnknownExtension = false)
    {
        RoumenAsset::addAfter($this->elixir($file1), $this->elixir($file2), $params, $onUnknownExtension);
    }
Add new asset after another asset in its array.

@param string       $file1
@param string       $file2
@param string|array $params
@param bool         $onUnknownExtension

@return void