title: Removing express and http from this socket.io example
body: <p>This is the example app found on the socket.io website:</p>
  
  <pre><code>var app = require('express')();
  var http = require('http').Server(app);
  var io = require('socket.io')(http);
  
  app.get('/', function(req, res){
    res.sendFile(__dirname + '/index.html');
  });
  
  io.on('connection', function(socket){
    console.log('a user connected');
  });
  
  http.listen(3000, function(){
    console.log('listening on *:3000');
  });
  </code></pre>
  
  <p>What if I truncate it to the following, removing the instances of <code>http</code> and <code>express</code>? What difference does it make writing the app this way instead?</p>
  
  <pre><code>const io = require("socket.io");
  const server = io.listen(3000);
  
  server.on("connection", function(socket) {
    console.log("user connected");
    socket.emit("welcome", "welcome man");
  });
  </code></pre>