Simple Javascript WebSocket Client

WebSocketClient.js

// This is a Websocket client (can be run in browser console) 
// ref client https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_client_applications
// The standalone server can be found here https://gist.github.com/patrikbego/447c40f8eaee709d7a6a2d2cadbfd046

const URL = 'ws://localhost:8000';
let websocket;

function updateStatus(status) {
  if (status === 'connected') {
    console.log('All good');
  }
}
function onOpen() {
  updateStatus('connected');
}
function onMessage(evnt) {
  if (typeof evnt.data === 'string') {
    console.log(evnt.data.substring(0, evnt.data.indexOf(':')));
    console.log(evnt.data.substring(evnt.data.indexOf(':') + 1));
  }
}
function onError(evnt) {
  alert(`ERROR: ${evnt.data}`);
}

function connect() {
  websocket = new WebSocket(URL);
  websocket.onopen = function (evnt) { onOpen(evnt); };
  websocket.onmessage = function (evnt) { onMessage(evnt); };
  websocket.onerror = function (evnt) { onError(evnt); };
}
function sendMessage() {
  websocket.send('Hello');
}