How to use express router

In earlier examples, we wrote all routing code in a single file App.js. But in real world scenarios, we have to split the code into multiple files.

We can create separate files and import them but express gives a router mechanism which is easy to use.

Create a separate file called route.js (name can be anything)

Create router using express −

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

exporting router −

module.exports = router;

Adding routing functions −

router.get('/add-username', (req, res,next)=>{
   res.send('<form action="/post-username" method="POST"> <input type="text" name="username"> <button    type="submit"> Send </button> </form>');
});
 router.post('/post-username', (req, res, next)=>{
   console.log('data: ', req.body.username);
   res.redirect('/');
});

Similar to functions we used in App.js for creating paths , we used router .

Import the router in App.js file −

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

add a middleware for using router in App.js file.

app.use(route);

with these changes the complete App.js file is −

const http = require('http');
const express = require('express');
const bodyParser = require('body-parser');
const route = require('./routes');
const app = express();
app.use(bodyParser.urlencoded({extended: false}));
app.use(route); app.use('/', (req, res,next)=>{
   res.send('<h1> first midleware: Hello Tutorials Point </h1>');
});
const server = http.createServer(app);
server.listen(3000);

route.js

const express = require('express');
const router = express.Router();
router.get('/add-username', (req, res,next)=>{
   res.send('<form action="/post-username" method="POST"> <input type="text" name="username"> <button    type="submit"> Send </button> </form>');
});
router.post('/post-username', (req, res, next)=>{
   console.log('data: ', req.body.username);
   res.redirect('/');
});
module.exports = router;

The router middleware should be placed before any url handling if present in App.js. Because code execution works from top to bottom in App.js file.

If any additional routers required , we can create separate files similar to routes.js and import it in App.js with another middleware in order for using that router.