express-middleware.js

var app = express()
var bodyParser = require('body-parser')

// third party middleware
// parse application/json
app.use(bodyParser.json())

// user defined middleware
app.use(function (req, res, next) {
  console.log('Time:', Date.now())
  next()
})

// use middleware for specific url path
app.use('/user/:id', function (req, res, next) {
  checkUser(req.params.id)
  next()
})