App.js for websocket-testing demo

App.js

//App.js
import React, { useState } from 'react'
const App = () => {
  const [message, setMessage] = useState('websocket is closed')
  return (
    <div className="App">
      <p id="websocket">{message}</p>
      <WebsocketHandler setMessage={setMessage} />
    </div>
  )
}
export default App
// WebsocketHandler does what the name suggests - 
// launch/close websocket client and receive messages
const websocketUrl = 'ws://127.0.0.1:5000'
const WebsocketHandler = ({ setMessage }) => {
  const ws = new WebSocket(websocketUrl)
  ws.onopen = () => {
    console.log('conn open')
    ws.send('connection is open')
  }
  ws.onmessage = (message) => {
    setMessage(message.data)
    console.log('onmessage triggered', message)
    ws.send('message received')
  }
  ws.onclose = () => {
    console.log('connection closed')
  }
  return null
}