Defferent Type of Nodejs Server Starting type

app.js

/// Type 1

var http = require('http');

http.createServer(function(req,res){
  // write your Code
}).listen(8000);


/// Type 2
var express = require('express');
var app = express();

app.set('port',process.env.PORT || 5100);
app.listen(app.get('port'),function(){
    console.log('Server Running');
});


// type 3
var http = require('http');

http.createServer(function (req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('Hello World!');
}).listen(8080); 

//type 4
var http = require('http');

//create a server object:
http.createServer(function (req, res) {
  res.write('Hello World!'); //write a response to the client
  res.end(); //end the response
}).listen(8080); //the server object listens on port 8080