Haml >= 4.0 includes built-in support for coffeescript.

Coffee-filter provides a custom haml filter allowing you to inline coffeescript in your haml templates. It was inspired by Ivan Nemytchenko’s coffee-haml-filter but I wanted an installable gem and “coffeescript” as the filter name.

Haml:

%div
  stuff
  :coffeescript
    alert 'here'

Html:

<div>
  stuff
  <script type='text/javascript'>
    //<![CDATA[
      (function() {
    alert('here');
  }).call(this);

    //]]>
  </script>
</div>

Add the following to your Gemfile:

gem 'coffee-filter'

Using Ruby interpolation within the :coffeescript block will prevent Haml from caching the result of compilation. This means that your coffeescript block will be compiled by the coffeescript engine on runtime during every request, which is something you’ll definitely want to avoid (since it’s orders of magnitude slower).

In other words, using constructs similar to this:

:coffeescript
  @server_time = #{Time.now.to_i}

will cost you around 100ms on each request. Either use the :javascript filter for this, or embed the dynamic content in some other way in the DOM.

Copyright © 2011 Paul Nicholson, released under the MIT license