Express middleware mounting patterns

app.js

const app = require('express');

app.use(require('./default-middleware'));
app.use(require('./router'));

module.exports = app;

auth.js

const router = require('express').Router();

const passport = require('passport');
const BasicStrategy = require('passport-http');
passport.use(new BasicStrategy((username, password, done) => {
  // Some Basic authentication...
}));

router.use(passport.authenticate('basic'));

router.use((err, req, res, next) => {
  // handle authentication errors
});

module.exports = router;

default-middleware.js

const router = require('express').Router();

router.use(require('./body-parser'));
router.use(require('./cookie-parser'));

module.exports = router;

router.js

const router = require('express').Router();

router.use('/', require('./routers/home'));

router.use('/user', require('./auth'), require('./routers/user'));

module.exports = router;