Cleaning up Web Sockets functions in React

cleanupWebSockets.js

useEffect(() => {
  const ws = new WebSocket(url, protocols)
  // do what you want with the socket
  ws.onmessage = (event) => {
    setValue(JSON.parse(event.data));
  };
  
  // cleanup the web socket when component unmout
  return () => ws.close()
}, [])