참고

Socket.IO - Chat

서버 세팅

npm install socket.io

const io = require('socket.io')(server);

io.on('connection', (socket) => {
  console.log('a user connected');

  socket.on('disconnect', () => {
    console.log('user disconnected');
  });

  socket.on('chat message', (message) => {
    const data = { id: Date.now(), ...JSON.parse(message) };
    io.emit ('chat message' , JSON.stringify(data));
  });
});

클라이언트

npm install socket.io-client

const socket = socketIO(apiUrl);

// ...

socket.on('connect', () => {
  console.log('connect socket');
});

socket.on('chat message', (message) => {
  const data = JSON.parse(message);
  setMessages(prev => prev.concat(data));
});