Express: composing middleware

Question

I want to move a series of app.use() calls into its own module. The easiest way to encapsulate this is to expose a function(app) in the exports, but I feel that handing over the app object is too much of an opaque interface.

I would like to expose a middleware to be app.use()'d from outside the module. I need to chain/compose the middlewares used internally.

Is there a stylish way of doing this, or an alternative? What's the easiest way of going about it? Anything I should avoid?

Answer 1

This answer is a little late, but here it goes anyway...

// composedMiddleware.js
const express = require('express')
const ware1 = (req, res, next)=>{...}
const ware2 = (req, res, next)=>{...}
const router = express.Router()
router.use(ware1)
router.use(ware2)
export default router

// app.js
const composedMiddleWare = require('./composedMiddleware.js')
app.get('/something', (req, res, next)=>{...})
app.get('/something', composedMiddleWare)

If the code isn't self-explanatory, then just note that routers are also middleware. Or, to put it more precisely, "a router behaves like middleware itself, so you can use it as an argument to app.use()" ref.