Collin Forrester

AngularJS, JavaScript, Node.js & Android enthusiast.
Web, mobile, and food developer.


About two weeks ago btford tweeted about an npm package called ExplainJS by bendytree. Looking into it some I found that it proved to be really useful for a couple of reasons. One, it encourages you to have legitimate comments that actually explain and contribute to your code. Two, it is super easy to use and outputs a really nice look page of annotated source code (similar to how you may have seen the BackboneJS source code).

Getting started

Actually getting started with the plugin was super easy. Over on the GruntJS website, they have a great guide for creating your own plugins. The following, shamelessly stolen from the grunt website, is how it's done in 6 steps:

  1. Install grunt-init with npm install -g grunt-init
  2. Install the gruntplugin template with git clone git:// ~/.grunt-init/gruntplugin
  3. Run grunt-init gruntplugin in an empty directory.
  4. Run npm install to prepare the development environment.
  5. Author your plugin.
  6. Run npm publish to publish the grunt plugin to npm!

One thing that wasn't completely obvious to me is that the plugin tests are already set up with grunt and all you need to run is grunt test. For some reason when I looked at the test, I thought it was going to be more work to set them up. So I've neglected to included them in this first releast. But hey, that's what 0.0.1 releases are for.

What It Does

You can get a full explanation here. But long story short, it parses your source code and formats your comments (block and inline) to side-by-side with your code. Here's an example of ExplainJS ran on the AngularJS source code.

The grunt plugin takes all that great functionality and wraps it in the build process that you know and love. It uses the standard grunt file/src format that you're used to also.

  explainjs: {
    files: {
      'dist/explainjs/explain.html': ['dist/scripts/scripts.js'],

If you're using yeoman (which you should be) to scaffold your stuff, a good spot to put your explainjs task is after concatenation but before minification.

grunt.registerTask('build', [
  'concat', // concat files here, gives me dist/scripts/scripts.js (not minified)
  'explainjs', // explain here

What's Left

Overall the grunt community makes it extremely easy to contribute and add to the already amazing plugin repository. Getting an initial plugin set up and scaffolded was painless. It felt good contribute back to an open source project and I would/will do it again when I get a chance.