No response from Socket.IO in Node.JS server - node.js

Question

Guys i've been struggled for this past days, from this socket.io setup. I thought there's should be no mistakes on my code. I've followed all tutorial and documentation on how to setup the server for socket.io using node and express. But still when i try to connect to this there are no response from the socket.io. On my client side i try to connect the same url as this server running http://localhost:8090 (FIXED)
SO EVERYTHING IS SET UP! the thing that it won't work is bcs i didn't set the CORS(see my edited code) on the socket instance on the server side.FYI since Socket.IO v3 u need to include the cors property by defining which url that gonna connected to ur socket.
Server Code:
const express = require ('express');
const bodyParser = require('body-parser');
const cookieParser = require('cookie-parser');
const db = require("./Connection/pg_pool");
const authentication = require("./Config/auth");
const connectionError = require("./Config/connectionError");
const cors = require('cors');
let port = 8090;
let hostname = 'localhost';
const midtransClient = require('midtrans-client');
const paymentConf = require('./Config/payment');
const { encode } = require('node-encoder');
const axios = require('axios');
let payment = paymentConf.paymentConf;
let errorMsg = connectionError.connectionError();
let auth = authentication.auth;
const app = express();
const server = require("http").createServer(app);
const io = require('socket.io')(server)
io.on("connection", socket => {
console.log('NEW USER CONNECTED')
});
app.use(express.json());
app.use(cors({origin: true, credentials: true}));
app.use(express.urlencoded({extended: true}));
app.use(cookieParser());
server.listen(process.env.PORT || port, hostname, () => {
console.log(`Listening to ${hostname}:${port}`)
})
Client Code:
import React, {useState, useEffect, useRef, useCallback, useMemo} from 'react';
import { io } from "socket.io-client";
const ENDPOINT = "http://localhost:8090";
let socket;
export default function Chat(props) {
const [text, setText] = useState('')
const [req, setReq] = useState([]);
const [messages, setMessages] = useState([]);
const [send, setSend] = useState(false);
useEffect(() => {
socket = io(ENDPOINT);
console.log('ini socker', socket.connected)
socket.on("connect", (data) => {
console.log(data)
});
}, []);
....
FIXED CODE
/*since my frontend (client-side) was running on localhost:3000,
all u need to do is just define the cors and put the origin url that
u gonna connect to ur socket instance on Node.Js (server) like this.*/
const io = require('socket.io')(server, {
cors: {
origin: [`http://localhost:3000`],
credentials: true
}
})