Develop and test your JavaScript applications as CommonJS modules in Node.js. Then Stitch them together to run in the browser.

npm install stitch

Bundle code in lib/ and vendor/ and serve it with Express:

var stitch  = require('stitch');
var express = require('express');

var package = stitch.createPackage({
  paths: [__dirname + '/lib', __dirname + '/vendor']
});

var app = express.createServer();
app.get('/application.js', package.createServer());
app.listen(3000);