Symfony2, twig and JavaScript

Question

What do I need to do to get twig to process a JavaScript file? I have an html.twig that uses a JavaScript twig. Something like this:

{% extends 'BaseBundle::layout.html.twig' %}

{% block javascripts %}
    {{ parent() }}
    {% javascripts
        '@BaseBundle/Resources/js/main.js.twig'
    %}
    {% endjavascripts %}
{% endblock %}

< more template omitted >

And parts of main.js.twig:

function testFunction()
{
    alert('{{VariableFromPHP}}');
}

And the controller:

/**
 * @Route("/",name="home")
 * @Template("MyBundle:Default:index.html.twig")
 */
public function indexAction()
{
   return array( 'VariableFromPHP' => 'Hello World');
}

I expected the JavaScript to look like this at run-time:

alert('Hello World');

But, the code is unchanged. Any ideas what I am doing wrong?

Thanks, Scott

Answer 1

My sugestion to use global variables:

{% javascripts '@AcmeBundle/Resources/public/js/*' output='js/compiled/main.js'%}
        <script>
            var TWIG = {};
            TWIG.variableOne   = "{{ path('rote_to_nowhere') }}";
            TWIG.variableTwo   = "{{ helloworldVar }}";
            TWIG.variableThree = "{{ "something"|trans }}";
        </script>
        <script type="text/javascript" src="{{ asset_url }}"></script>
{% endjavascripts %}

then you can use it in your js file:

alert(TWIG.variableTwo);

Answer 2

Assetic does not include twig templates; you should create a separate controller for the javascript file. Although I would consider it bad practice performance-wise, because you will have to process two requests this way.

/**
 * @Route("/main.js")
 */
public function mainJsAction() {
    $params = array( 'test' => 'ok' );
    $rendered = $this->renderView( 'MyBundle:Default:main.js.twig', $params );
    $response = new \Symfony\Component\HttpFoundation\Response( $rendered );
    $response->headers->set( 'Content-Type', 'text/javascript' );
    return $response;
}

{% extends 'BaseBundle::layout.html.twig' %}

{% block javascripts %}
    {{ parent() }}
    <script type="text/javascript" src="{{ path('my_default_mainjs') }}"></script>
{% endblock %}

An alternative is to dump dynamic variables in the html, and only use static javascript files.