Not connecting to sockets?

Question

Node.js

Customer:

import { io } from "socket.io-client";
io('ws://127.0.0.1:5000/')

Server:

const app = express()
const server = require('http').createServer(app)
const socketIO = require('socket.io')
const io = new socketIO.Server(server)

io.on("connection", (socket) => {
   console.log(socket.id);
})

The API is located at 127.0.0.1:5000 and an error occurs when trying to connect to a socket at this address

GET http://127.0.0.1:5000/socket.io/?EIO=4&transport=polling&t=NlJrC6b net::ERR_CONNECTION_REFUSED

Answer 1

the error was related to CORS and some parameters needed to be specified:

const io = require('socket.io')(server, {
   cors: {
      origin: "http://localhost:8080",
      methods: ["GET", "POST"]
   }
})