WebSockets Typed with `ws`

Install ws

npm i ws
npm i -D @types/ws

Server

import { WebSocketServer } from 'ws';

const wss = new WebSocketServer({ port: 8081 });

wss.on('connection', ws => {
  ws.on('message', (msg: string) => {
    console.log('←', msg);
    ws.send(`echo: ${msg}`);
  });
});

Client (browser)

const socket = new WebSocket('ws://localhost:8081');
socket.addEventListener('open', () => socket.send('hello'));
socket.addEventListener('message', e => console.log('→', e.data));

Typed messages

type ChatMessage = { type: 'chat'; payload: string };

socket.send(JSON.stringify({ type: 'chat', payload: 'Hi' } as ChatMessage));