Rex is "commonjs in the browser".

It's available through npm:

npm install rex

There is also a cli program available

npm install -g rex-cli
rex --help

Usage is simple:

var rex = require('rex');
var parse = rex();

parse('test.js', function(err, compiled) {
	// this outputs test.js compiled for browser usage
	console.log(compiled);
});

Your browserside javascript can now use require to require other modules and exports and module.exports just like in node.js. Additionally if your module exports a global variable with the same name as your module require will still work!
If you require a module like require('my-module') rex will look for it in the nearest browser_modules or node_modules folder. If rex can't resolve a module name, no error is raised, instead require returns null on runtime.

// browserside code
var foo = require('./foo'); // will look for foo.js in the same folder
var bar = require('bar');   // will look for bar.js or bar/index.js in 
                            // the nearest browser_modules or node_modules folder

module.exports = function() { // will export a function
	return 'hello from module';
};

You can pass a set of options with rex(options). They include:

• base: Specify a base js file. Rex will now assume that base's dependencies are loaded for all other requests.
• dependencies: A map of global dependencies to be loaded in the client. This could be jQuery from a cdn i.e. {jQuery:'https://cdn.com/jQuery.js'}.

MIT