how to split index.js to routes nodejs

// index.js

const express = require('express');
const app = express();
const port = 3000;

// Home route
app.get('/', (req, res) => {
  res.send('Hello World!');
});

// About route
app.get('/about', (req, res) => {
  res.send('About us page');
});

// Contact route
app.get('/contact', (req, res) => {
  res.send('Contact us page');
});

app.listen(port, () => {
  console.log(`Server is running on port ${port}`);
});

// routes/home.js

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

router.get('/', (req, res) => {
  res.send('Hello World!');
});

module.exports = router;

// routes/about.js

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

router.get('/about', (req, res) => {
  res.send('About us page');
});

module.exports = router;

// routes/contact.js

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

router.get('/contact', (req, res) => {
  res.send('Contact us page');
});

module.exports = router;

// index.js

const express = require('express');
const app = express();
const port = 3000;

// Import route modules
const homeRoute = require('./routes/home');
const aboutRoute = require('./routes/about');
const contactRoute = require('./routes/contact');

// Use route modules
app.use('/', homeRoute);
app.use('/', aboutRoute);
app.use('/', contactRoute);

app.listen(port, () => {
  console.log(`Server is running on port ${port}`);
});