Why do some developer use 'http' and 'express' to create the server? [duplicate]

Question

Particularly on this line of code:

I'm kinda new on node.js and most of the tutorials that I've seen initialize the server by

var http = require('http');
var express = require('express');

app = express();

//omit

http.createServer(app).listen(1337)

wherein, if you're already using express then you can just do :

var express = require('express');
var app = express();

// omit

app.listen(1337,function(){

});

Are there any major difference between those two code structures?

Answer 1

No meaningful difference. In fact, if you look at the code for app.listen(), all it does is do http.createServer() and than call .listen() on it. It's just meant to be a shortcut that saves you using the http module directly.

Here's the code for app.listen():

app.listen = function listen() {
  var server = http.createServer(this);
  return server.listen.apply(server, arguments);
};

Your second code block is just a bit less code because it uses the app.listen() shortcut. Both do the same.