Difference between RequireJS and CommonJS

Question

I was wondering what the difference between these snippets is.

var $ = require(\'jquery\');
var _ = require(\'underscore\');
var BackBone = require(\'backbon         


        

Answer 1

The former snippet adheres to the CommonJS spec, which outlines how modules are to be exported/transported to be used in other modules.

So, you could write code which could look like this

src/ExpressModule.js

var express = require('express');
// do initialization
exports.express = express;

And then you can use it like this

src/UserExpressModule.js

var express = require('./ExpressModule');
// do something else

CommonJS spec was built primarily for server side environments, and by extension, is used in Node.js

On the other hand of the spectrum is AMD, most notably implemented by RequireJS. AMD was built for browser environments, or client-side code, and here you can use and define modules like the latter snippet in your code

A sample use could be like this

src/main.js

requirejs.config({
    baseUrl: '../vendor'
    path: '../src'
});
require(['jquery', 'underscore', 'backbone'], function($, _, Backbone) {
    // do some client side computation here
});

You can then include this main.js file in your index.html like so

Essentially, CommonJS and AMD are at their core specifications for modularizing Javascript, but are aimed at different execution environments.