title: How to create multiple Node.js websockets on relative path
body: <p>For example, if I want to run:</p>
  
  <pre><code>var http = require('http');
  var s = http.createServer();
  var WebSocket = require('ws');
  var WebSocketServer = WebSocket.Server;
  s.on('request', (request, response)=&gt;{
  // other codes
  });
  s.listen(process.env.PORT || 3000);
  var a = new WebSocketServer('/a');
  var b = new WebSocketServer('/b');
  var c = new WebSocketServer('/c');
  </code></pre>
  
  <p>So ideally I want <code>a</code> to be <code>process.env.host:process.env.PORT/a</code>, likewise for <code>b</code> and <code>c</code>. How will this be done? What's the correct syntax?</p>