NodeJS

What is Node.js?

Node.js is an open-source, cross-platform runtime environment for developing server-side and networking applications. Node.js applications are written in JavaScript and can be run within the Node.js runtime on OS X, Microsoft Windows, and Linux.

Node.js also provides a rich library of various JavaScript modules which simplifies the development of web applications using Node.js to a great extent

            The definition of Node.js as supplied by its official documentation is as follows:

`Node.js is a platform built on Chrome's JavaScript runtime for easily building fast and scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.`

Qualities of NodeJS

• Asynchronous and Event Driven − All APIs of Node.js library are asynchronous, that is, non-blocking. It essentially means a Node.js based server never waits for an API to return data. The server moves to the next API after calling it and a notification mechanism of Events of Node.js helps the server to get a response from the previous API call.
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• Very Fast − Being built on Google Chrome's V8 JavaScript Engine, Node.js library is very fast in code execution.
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• Single-Threaded but Highly Scalable − Node.js uses a single-threaded model with event looping. Event mechanism helps the server to respond in a non-blocking way and makes the server highly scalable as opposed to traditional servers which create limited threads to handle requests. Node.js uses a single-threaded program and the same program can provide service to a much larger number of requests than traditional servers like Apache HTTP Server.
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• No Buffering − Node.js applications never buffer any data. These applications simply output the data in chunks.
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• License − Node.js is released under the MIT license
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Features

               Non-blocking  - 

•       Program returned immediately, continue execute.
•       Program has an event loop
•       Program informed when data ready event emitted, through call back

                Event-Driven  - 

•       This is the key feature of Nodde.js
•       Support async event like AJAX

Where to Use Node.js?

Following are the areas where Node.js is proving itself as a perfect technology partner.

• I/O bound Applications
• Data Streaming Applications
• Data Intensive Real-time Applications (DIRT)
• JSON APIs based Applications
• Single Page Applications

                    Say Hellow World with NodeJs!

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