JSWebBuilder

This gem is a simple little hack to introduce some teeny-weeny bit of JavaScript asset pipeline management to my sinatra web applications. And since I like rake the whole thing is basically a custom rake task.

This gem exists to allow for a more modular javascript development approach. It therefore does exactly and only the following things and in that order:

1. It reads all files in a given directory
2. For each file it searches for a special //= require statement
3. It concatenates all in this manner required files into one and writes it to an output file

For a more detailed description look under the usage section.

The whole reason I did this gem is, because I spectacularly failed trying to integrate sprockets into my application. And having the functionality within my application and testing it there, while using it gave me nervous ticks.

So I did this. Even though there are most likely 42 other gems or methods to do exactly this. If you nevertheless like my little piece of code, feel free to use it. If you find a bug or want to add something, report it or create a pull request. If you think I am a moron for doing this, be polite and keep it to yourself.

I currently don't plan to publish on rubygems.org, so you have to use the respective github extension.

Add this line to your application's Gemfile:

gem 'js_web_builder', :git => "https://github.com/quams/js_web_builder.git"

And then execute:

$ bundle

Or install it fresh from the source via:

$ gem install specific_install
$ gem specific_install https://github.com/quams/js_web_builder.git

Or clone it somewhere and then install it (see section Development).

JSWebBuilder as basically nothing more than a simple implementation of Rake::TaskLib in the style of Rake::TestTask.

It consecutively reads all the files matching a pattern (default: "*.js") within the root-level of an array of input directories. It scans each of the input files for the following pattern:

//= require relative_path/filename

You might notice: That is not surprisingly the same syntax sprocket uses. So if you ever need or want to go down that road, you do not need to change too many things.

The interpretation of the requires is pretty simple and adheres strictly to the following rules:

1. Relative path: All includes are relative to the file read. In my cases required files are either in the same directory, or more likely, in a subdirectory.
2. Order: JSWebBuilder follows the order of the require statements when concatenating. The end of the concatenated file will be the input file.
3. No recursion: The required files are not interpreted at all. In principle that would be simple, bu I currently really have no desire to implement a endless-loop detection.

That's basically it, there is really not any magic at all involved!

TBD

Imagine the following tree for the javascript files of our web application:

assets/js    
├── lib
│   ├── fu.js
│   ├── module1.js
│   ├── module2.js
│   └── module3.js
├── main.js
└── minime.js

And minime.js looking like this:

//= require lib/module1.js
//= require lib/module3.js

// The Big Document Ready Guard with the main implementation
$( document ).ready(function() {
  // do stuff here
}); // document ready

Include this code in the respective Rake file:

JSWebBuilder::BuildTask.new(:build_js) do |b|
    b.outdir     = File.join(File.dirname(__FILE__),"public/js/")
    b.inputdirs << File.join(File.dirname(__FILE__),"assets/js/")
end

And the resulting minime.js in the public/js folder is the equivalent of the following shell command:

$ cat assets/js/lib/module1.js assets/js/lib/module3.js assets/js/minime.js > public/js/minime.js

I might want to add the following in the near future:

• Make it a "real" gem, e.g. pushing it to rubygems.org
• Include post-processors, eg. uglifier or Closure Compiler
• Make an exclude pattern
• lib path
• Make a manifest-based clean target

Or I just give sprockets another try...

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org (well, the last part is only in here, so that I won't forget it whenever it becomes interesting).

Bug reports and pull requests are welcome on GitHub at https://github.com/quams/js_web_builder.