Build a simple WebSocket server

const server = Bun.serve<{authToken: string}>({
	fetch(req, server) {
		const success = server.upgrade(req);
		if (success) {
			// Bun automatically returns a 101 Switching Protocols
			// if the upgrade succeeds
			return undefined;
		}

		// handle HTTP request normally
		return new Response('Hello world!');
	},
	websocket: {
		// this is called when a message is received
		async message(ws, message) {
			console.log(`Received ${message}`);
			// send back a message
			ws.send(`You said: ${message}`);
		},
	},
});

console.log(`Listening on ${server.hostname}:${server.port}`);