middleware-now.js

// a.js
module.exports = async (req, res) => {
  await middleware(req, res)
}

// b.js
module.exports middleware( async (req, res) => {
  // ...
})

// express.js
var app = express()

app.use('/user/:id', function (req, res, next) {
  console.log('Request Type:', req.method)
  next()
})

app.get('*', (req, res, next) => {
  res.send('USER')
})