Websockets with nodejs express server using single port

index.html

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/[email protected]/css/xterm.css"/>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/lib/xterm.js"></script>
<div id="terminal">
<script>
var terminal = new window.Terminal({cursorBlink: true});
terminal.open(document.querySelector('#terminal'));
terminal.onData(e => socket.send(e));

var socket = new WebSocket(document.location.href.split("http").join("ws") + "terminal");
socket.onmessage = msg => terminal.write(msg.data);
socket.onopen = () => {
  console.log("socket opened");
  terminal.focus();
}
socket.onclose = () => console.log("socket closed");
</script>

server.js

const express = require('express');
const protocol = require("http");
const app = express();
const ws = require('ws');
const child_process = require('child_process');
const websocket = new ws.Server({ noServer: true, rejectUnauthorized: false })
const port = 9999;

app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
});

app.get("/terminal", (req, res) => {
  websocket.handleUpgrade(req, req.socket, req.headers, socket => {
    websocket.emit('connection', socket);
  });
  return true;
});

app.get('*', (req, res) => {
  res.sendFile(__dirname + "/" + req.params[0]);
});

protocol.createServer(app).listen(port, () => {
  console.log(`Server listening at port ${port}`)
})

websocket.on("connection", conn => {
  console.log("Websocket connected")
  var shell = child_process.spawn("podman", "run -it ubuntu bash".split(" "));
  shell.stdout.setEncoding('utf8')
  shell.stdout.on("data", data => conn.send(data));
  conn.on("message", data => shell.stdin.write(data));
  conn.on("close", () => {
    console.log("Websocket disconnected");
    shell.stdin.pause();
    shell.kill();
  });
  conn.onerror = function () {
    console.log("Websocket comm error")
    shell.stdin.pause();
    shell.kill();
  }
});