Adding 404 page in express

Now we have a App.js and route.js for handling routes. For any other http requests for which we have not added any request handling will results into an error page. Example for url ‘test’ −

App.js

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); const server = http.createServer(app); server.listen(3000);

Showing meaningful error message on incorrect url’s−

We can add a all catch middleware for incorrect url at the end of all middleware’s in App.js −

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> Page not found </h1>'); }); const server = http.createServer(app); server.listen(3000);

The last middleware is a request handler if no request handler is found and returns a response. From this all catch middleware we can send message for incorrect paths.

Now for any incorrect path we see below output on browser −

We can use separate router from express and add it in the last by order respective other routers.

Sending 404 status code −

app.use((req, res,next)=>{    res.status(404).send('<h1> Page not found </h1>'); });

We can chain other functions like setHeader in the response before sending actual message.

res.setHeader(‘’).send(‘’);