With Assetic / Twig / Symfony2, can I define front end libraries?

Question

I'm using Symfony2, with Assetic and Twig. I have various frontend libraries - Backbone, jQuery, jQuery UI, and Bootstrap. Both Bootstrap and jQuery UI include CSS and JS files.

Is there a way that I can define the resources they need to include (including dependencies), and then in Twig / Assetic just include all those resources in one tag? What I'd look to have is something like:

// config.yml <!-- DOES NOT WORK -->
assetic:
  resources:
    jquery:
      js: /filepath/to/jquery.js
    jquery_ui:
      dependencies: jquery
      css: /filepath/to/jqueryui.css
      js: /filepath/to/jqueryui.js
    less:
      js: /filepath/to/less.js
    bootstrap:
      dependencies: { less, jquery }
      js: /filepath/to/bootstrap.js
      css: /filepath/to/bootstrap.css
    backbone:
      dependencies: { jquery }
      js: { /filepath/to/underscore.js, /filepath/to/backbone.js }

// view.html.twig
{% use jquery_ui %}
{% use bootstrap %} 

// outputs all js and css for jQuery, jQueryUI, Less, Backbone, and Bootstrap

I found a couple of related questions:

• How to define Assetic resources in Symfony 2 yml or xml configuration file?
• Symfony2 Assetic + Twig Template JavaScript Inheritance

but neither seems to involve defining the resources in config.yml. Instead, they define them in base.html.twig but that's what I'm trying to avoid.

I tried using the use tag in Twig, by defining a template called 'jquery_ui' and using {% stylesheets %} and {% javascripts %} in that block and then in base.html.twig putting {% use "jquery-ui.html" %}. However, use won't import the template because it has a body.

Answer 1

Although there is indeed support for defining front-end libraries, there is unfortunately no support for dependency resolving. You must also define your CSS and JavaScript separately.

What I have been doing, is creating a separate file in /app/config/ called assets.yml and including it in the main configuration to keep things clean.

assetic:
    assets:
        jquery:
            inputs:
                - '%kernel.root_dir%/Resources/public/js/jquery.js'
                - '%kernel.root_dir%/Resources/public/js/jquery-ui.js'
        my_lib:
            inputs:
                - '%kernel.root_dir%/Resources/public/js/my-custom-lib.js'
                - ...

Note that ´%kernel.root_dir%´ resolves to the app directory by default in Symfony2. You may now use the assets in your Twig templates.

{% block javascripts %}
    {% javascripts '@jquery' '@my_lib' output="js/jquery.js" %}
        <script type="text/javascript" src="{{ asset_url }}"></script>
    {% endjavascripts %}
{% endblock %}

The same could be done for CSS files. The example also demonstrates why it's not possible to define CSS and JavaScript as a single asset.