jekyll-jsminify

This is an absolute barebones JavaScript and CoffeeScript minifer for Jekyll. For something extraordinary that covers all use cases, I suggest jekyll-assets.

In your _config.yml file, add this gem:

gems:
  - jekyll-jsminify

With Jekyll, you can fake out concatenation of multiple JavaScript/CoffeeScript files.

For example, if you have a file called application.js that looks like this:

---
---
{% include assets/javascripts/foo.js %}
{% include assets/javascripts/bar.js %}
{% include assets/javascripts/js.js %}

or a file called application_cs.js that looks like this:

---
---

$ = jQuery # this avoids load errors with CoffeeScript coming after jQuery

{% include assets/coffeescripts/foo.coffee %}
{% include assets/coffeescripts/bar.coffee %}
{% include assets/coffeescripts/cs.coffee %}

You'll create two files called application.js and application_cs.js, respectively, that contain the content of all our JS/CS assets.

Assuming you set your content up like that, this plugin will run uglifier to compress the code.

You don't need to do anything special in your layouts; keep the same inclusion syntax is okay:

<script src="{{ site.baseurl }}/assets/javascripts/application.js"></script>
<script src="{{ site.baseurl }}/assets/javascripts/application_cs.js"></script>

You can add the jsminify key to your config.yml file, and pass in any uglifer options you like:

jsminify:
     :mangle:
        :eval: true