node package manager


Punk, carefree Browser-side Javascript Asset Bundling for Express sites

Cassette Express

The short version: CI friendly Javascript asset bundling for those of us who don't want to rewrite our client side Javascript as CommonJS modules

The long version:

  • Reference a Javascript file in your template. Get it, and all dependencies, in the right order, in the page.
  • CI Friendly. No separate build process. No command line tools.
  • Declare dependencies as comments, i.e, // @reference ../lib/jquery.1.7.2.js
  • Reference entire directories instead of individual files with // @reference ../lib
  • Debug mode returns individual javascript files to the browser and dynamically responds to your changes.
  • Production mode bundles all javascript into a single minified download using Uglify.

Because this isn't a CommonJS based system, you can use all the same javascript libraries and files you're already using. You can even use it with Ender, too, by referencing the unminified version, ie., // @reference ../lib/ender.js.

Working, unstable

  • Some test coverage for debug and production mode specific behaviours not there yet
  • Insufficient documentation.

Cassette-Express is an adaptation of Andrew Davey's Cassette (, a .net package which helps developers manage CSS, Javascript, Coffeescript assets. It is pretty bloody useful.

npm install cassette-express
cd node_modules/cassette-express
npm install

In typical ExpressJS app.js file, assuming you're still using the default /public/javascripts

// debug mode, every request the files are checked for changes & individual file downloads.
var cassette = require('cassette-express')();

// or production mode, generated once per restart. One single minified download.
var cassette = require('cassette-express')({ mode : 'production' });

A little later on in app.js we make sure we have access to Cassette inside the templates..

app.set('view options', {
	assets : cassette.middleware()

Then in our template, i.e, layout.jade:

!= assets.useAsset('/app/client-app.js')

Which, in debug mode, would output something like...

<script src="/javascripts/lib/jquery.js"></script>
<script src="/javascripts/lib/jquery-someplugin.js"></script>
<script src="/javascripts/lib/jquery-some-other-plugin.js"></script>
<script src="/javascripts/lib/underscore.js"></script>
<script src="/javascripts/lib/my-own-library-stuff.js"></script>
<script src="/javascripts/app/app-namespace.js"></script>
<script src="/javascripts/app/features/navigator.js"></script>
<script src="/javascripts/app/features/content.js"></script>
<script src="/javascripts/app/client-app.js"></script>

And in production mode all those scripts are merged, minified and then you get...

<script src="/javascripts/cassette/AEEE546E7B7C7BCEBC.min.js"></script>

By default the compiled files are put in /public/javascripts/cassette.

The gathering and sorting of dependencies is done automatically. In debug mode bundles are reassembled if there are any changes to teh sources. In production mode, node must be restarted before a new minified bundle is generated.

  • Bundles are automatically generated by requesting any particular resource inside templates. You don't need to pre-reference them.
  • Bundles will always be one single file in production mode, not multiple files depending on how they were pre-referenced.
  • No automagic coffeescript compiling. Poor Coffeescript.
  • No stylesheet merging/compiling.
  • Significantly less features. Ha.