Q:

Express middleware on folder mounted app

I have an Express.js application running on https://mydomain.tld/folder. It sets up the route middlewares with
app.use('/path', middleware)

but only the one for the '/' path is working properly. I'm guessing this is because Express is looking for requests on https://mydomain.tld/path instead of on https://mydomain.tld/folder/path. 
How can I get Express to process the requests for https://mydomain.tld/folder/path (preferably without having to hard code the path)?

A:

Using a router:
// myRouter.js

var express = require('express')
var router = express.Router()

router.get('/path', middleware)

// other routes...

module.exports = router

Now you can use your router with the relative path you want:
var myRouter = require('./myRouter')

app.use('/folder', myRouter)

