import React, { useState, useEffect } from "react";
import socketIOClient from "socket.io-client";
const ENDPOINT = "http://127.0.0.1:4001";

function App() {
  const [response, setResponse] = useState("");

  useEffect(() => {
    const socket = socketIOClient(ENDPOINT);
    socket.on("FromAPI", data => {
      setResponse(data);
    });
  }, []);

  return (
    <p>
      It's <time dateTime={response}>{response}</time>
    </p>
  );
}

export default App;

// with npm
npm install socket.io

// with yarn
yarn add socket.io

$ npm install socket.io

const express = require('express');const app = express();const http = require('http');const server = http.createServer(app);const { Server } = require("socket.io");const io = new Server(server);app.get('/', (req, res) => {  res.sendFile(__dirname + '/index.html');});io.on('connection', (socket) => {  console.log('a user connected');});server.listen(3000, () => {  console.log('listening on *:3000');});