Verify that the response header is text/html, to avoid problems when returning an image for example.
https://gist.github.com/miguelbalboa/9224ecc1daeadff5ab49

minifying only text/html output

// HTML Minification
    if(App::Environment() != 'local')
    {
        if($response instanceof Illuminate\Http\Response)
        {
            $output = $response->getOriginalContent();
            if($response->headers->get('content-type') == 'text/html; charset=UTF-8')
            {
                // Clean comments
                $output = preg_replace('/<!--([^\[|(<!)].*)/', '', $output);
                $output = preg_replace('/(?<!\S)\/\/\s*[^\r\n]*/', '', $output);
                // Clean Whitespace
                $output = preg_replace('/\s{2,}/', '', $output);
                $output = preg_replace('/(\r?\n)/', '', $output);
                $response->setContent($output);
            }
        }
    }

This code has an important error. Run the full content of the page twice. The first to generate the page, and the second to go through the :: after. That doubles the load times. I think it's worse than spending the HTML uncompressed. You can do the test by putting a log on a page and see that the refresh the log is printed twice.