web socket chat app

chat_server.js

const express = require('express');
const http = require('http');
const WebSocket = require('ws');

const port = 8989;
const server = http.createServer(express);
const wss = new WebSocket.Server({ server })

wss.on('connection', function connection(ws) {
  ws.on('message', function incoming(data) {
    wss.clients.forEach(function each(client) {
      if (client !== ws && client.readyState === WebSocket.OPEN) {
        client.send(data);
      }
    })
  })
})

server.listen(port, function() {
  console.log(`Server is listening on ${port}!`)
})

index.html

<center><h1>WS Chat App</h1></center>
<pre id="messages" style="height: 400px; overflow: scroll"></pre>
<input type="text" id="messageBox" placeholder="Type your message here" style="display: block; width: 100%; margin-bottom: 10px; padding: 10px;" onkeyup="validateInput(event)"/>
<button id="send" title="Send Message!" style="width: 100%; height: 30px;">Send Message</button>

<script>
  (function() {
    const sendBtn = document.querySelector('#send');
    const messages = document.querySelector('#messages');
    const messageBox = document.querySelector('#messageBox');

    let ws;

    function showMessage(message) {
      if (message instanceof Blob) {
        reader = new FileReader();

        reader.onload = () => {
        //   console.log("Result: " + reader.result);
          messages.textContent += `\n\n${reader.result}`;
        };

        reader.readAsText(message);
      } else {
        console.log("Result: " + message);
        messages.textContent += `\n\n${message}`;
      }

      messages.scrollTop = messages.scrollHeight;
      messageBox.value = "";
    }

    function init() {
      if (ws) {
        ws.onerror = ws.onopen = ws.onclose = null;
        ws.close();
      }

      ws = new WebSocket('ws://localhost:8989');
      ws.onopen = () => {
        console.log('Connection opened!');
      }
      ws.onmessage = ({ data }) => showMessage(data);
      ws.onclose = function() {
        ws = null;
      }
    }

	
    sendBtn.onclick = function() {
      if (!ws) {
        showMessage("No WebSocket connection :(");
        return ;
      }

      ws.send(messageBox.value);
      showMessage(messageBox.value);
    }
	
	
	messageBox.onkeyup = function() {
		if(event.keyCode  == 13) {
			if (!ws) {
				showMessage("No WebSocket connection :(");
				return ;
			}

			ws.send(messageBox.value);
			showMessage(messageBox.value);
		}
    }

    init();
  })();
</script>