Node JS

• A javascript runtime environment that executes the Javascript code outside of a browser. It can run on various platforms (Windows, Linux, Unix, Mac OS X, etc..)

Basic

• Save the below code in a "firstNode.js" file

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

• run the below command and open http://localhost:8080 in browser

d:\> node firstNode.js

Modules

• Modules is a wrapper on set of functions. Similar to libraries. In the above example "http" is a module and by writing require('http') we will have access to HTTP module and its functionalities (like create server).

Custom Module

• Add below code and create a file "firstmodule.js"

exports.myDateTime = function () {
  return Date();
};

• Use it as below

var dt = require('./myfirstmodule');    -- file path
console.log(dt.myDateTime());