TypeError: app.use() requires middleware functions

const express = require('express');
const bodyParser = require('body-parser');
const cookieParser = require('cookie-parser');

const app = express();
app.use(bodyParser.urlencoded({extended: false}));
app.use(cookieParser());

// tells express which template engine to use
app.set('view engine', 'pug');

const routes = require('./routes');

app.use(routes);

app.use((req, res, next) => {
    console.log('Hello');
    next();
});
app.use((req, res, next) => {
    console.log("World");
    next();
});

app.use((req, res, next) => {
    const err = new Error('Not Found');
    err.status = 404;
    next(err);
});

app.use((err, req, res, next) => {
    res.locals.error = err;
    res.status(err.status);
    res.render('error');
});

app.listen(3000, () => {
    console.log('The application is running on localhost 3000');
});

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

router.get('/', (req, res) => {
    const name = req.cookies.username;
    if (name) {
        res.render('index', {name});
    } else {
        res.redirect('/hello');
    }
});

router.get('/cards', (req, res) => {
    // another way to do it
    //res.locals.prompt = "Who is buried in Grant's tomb?"
    res.render('card', {prompt: "Who is buried in Grant's tomb?"});
});

router.get('/hello', (req, res) => {
    const name = req.cookies.username;
    if (name) {
        res.redirect('/');
    } else {
        res.render('hello');
    }
});

router.post('/hello', (req, res) => {
    res.cookie('username', req.body.username);
    res.redirect('/');
});

router.post('/goodbye', (req, res) => {
    res.clearCookie('username');
    res.redirect('/hello')
});

module.experts = router;