Beginner to socket io. Need help with connection

[Naveenravi07]

hi i am creating a classmanagement system with socket io . i need help with the connection . I am using expressjs as backend .

in my routes folder i have a file named index.js and this is how it looks like

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

const app = require("../app");
var http = require("http").Server(app);
var io = require("socket.io")(http);
/* GET home page. */

io.on('connection', socket => {
console.log("new connection");
})
router.get('/', function (req, res, next) {
res.render('index');
});

router.get('/createclass', (req, res) => {

})
module.exports = router;

in the rendering of this route i have a file named index.hbs where i configured the client side of socket io

<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/4.5.1/socket.io.js"></script>

<script type="text/javascript"> let socket=io() socket.on('connect',()=>{ console.log("connected newwwwwwwwww") }) </script>### some content

when i visit my localhost mainroute the browser console always shows me this error in each 5 seconds .