About nodejs server.listen()
<p>I just started to learn about nodejs servers and websockets.
Said I have this server written in javascript using socket.io and express.  </p>

<pre><code>var app = require('express')(),
    server = require('http').Server(app),
    io = require('socket.io')(server),
    port = process.env.PORT || 8080;
</code></pre>

<p>Is there any difference between:</p>

<pre><code>server.listen(port, function(){
    console.log("listening port " + port);
});
</code></pre>

<p>and</p>

<pre><code>server.listen(port);
console.log("listening port " + port);
</code></pre>

<p>Apparently they work the same.</p>

<p>So what actually server.listen() do?</p>