Express example using Router

app.js

var express = require('express');

var routes = require('./routes/index');
var users = require('./routes/users');

var app = express();

var port = process.env.PORT || 3000;

// path matching / will be handled by routes/index.js.
// index.js is set up with a '/something' subroute which can 
// be accessed now with /something ,
// as well as a '/' subroute which can be accessed with '/'
app.use('/', routes);

// path matching /users/ will be handled by routes/users.js.
// Set a path '/users' and then within that path, the routes are processed.
// Basically, it takes path matching '/user/(whatever the matching routes are in users.js router)'.
// Paths defined in users.js router are the users/ subroutes.
// In this example, users is only set up with '/' path so 
// it will respond to paths matching '/users/'
app.use('/users', users);

app.listen(port);