nested-express-router.js

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

var sub = express.Router()
var sub2 = express.Router()

sub2.get('/c', function(req, res, next, base) {
  res.send('sub test!!')
})

sub.use('/b/', sub2)
app.use('/a/', sub)

var server = app.listen(3000, function() {
  console.log('Listening on port %d', server.address().port)
})