Node.js is a JavaScript runtime environment that allows JavaScript to be used for server-side scripting. It uses non-blocking I/O and event-driven architecture, allowing it to handle multiple concurrent connections efficiently. Some key features of Node.js include asynchronous I/O, an event-driven model, callbacks, and the npm package manager. While Node.js has advantages like scalability, it is single-threaded and lacks standard libraries, making it best suited for real-time applications like chat and games rather than CPU-intensive tasks.

1. Server Side Apocalypse,
JS

2. About Me
Md. Sohel Rana
Founder, NerdDevs
http://www.nerddevs.com
twitter : @sohel023010
skype : sohel023010
http://blog.sohel.me

3. Client
Browser
A Desktop App
Rest Client
Server? Yes!

4. Server
Serves data, images, files, audio, video etc.
Sometimes foods as well! Foodpanda 

5. Server Side Scripting
ASP, ASP.NET, Java, PHP, Haskell, Perl,
Python, Ruby and so on!
And also JavaScript
JavaScript brought non-blocking IO
It changed the way how server works
We got NodeJS

6. NodeJS
A runtime environment
to support JavaScript
as server side
language
Built on V8-JavaScript
Engine of Chrome,
Fast
Event-driven, non-
blocking I/O

7. NodeJS
Advantages over others
- Asynchronous I/O, more request can server
- JavaScript as a Server Side language
- Event Driven
- Callbacks
- A good package manager “NPM”
Disadvantages
- Single threaded
- Lack of standard libraries

8. NodeJS
An http server :
var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello Worldn');
}).listen(9000, '127.0.0.1');
console.log('Server running at http://127.0.0.1:9000/');

9. Node Modules
A functional unit that
performs specified
actions
Loaded using
require(‘module_name’
)
Usually placed at
node_modules folder
Non-native modules
loaded searching
upwards

10. Node Modules
A simple module :
// “modules/calculator.js”
exports.add = function(a, b){
return a+b ;
};
exports.subtract = function(a, b){
return a-b;
};
var Calculator = require('./module/calculator.js');
var addTwoNumber = Calculator.add(5,7);

11. NPM
NPM- nodejs
package manager
Used for
install/uninstall node
programs
Can be used to
install dependencies
package.json is used
to define
dependencies
//pakage.json
{
"name": "backbone-express-boilerplate",
"version": "1.0.0",
"scripts": {
"start": "node ./server/bin/www"
},
"dependencies": {
"express": "^4.12.3",
"body-parser": "~1.12.0",
"cookie-parser": "~1.3.4",
"jade": "~1.9.2",
"serve-favicon": "~2.2.0"
},
"repository": {
"type": "git",
"url": "https://github.com/sohel-
rana/backbone-express-boilerplate.git"
},
"author": "Sohel Rana”,
"bugs": {
"url": "https://github.com/sohel-
rana/backbone-express-boilerplate/issues"
},
"homepage": "https://github.com/sohel-
rana/backbone-express-boilerplate"
}

12. Web Frameworks
NodeJS provides core
modules
Requires lots of effort
for web apps
Express, Sails etc.
provides lots of feature
top of it
Makes the project
manageable

13. Case Studies
LinkedIn moved from Rails to Node, reduced
their server uses from 30 to 3
Microsoft, Walmart, eBay, Paypal all uses nodejs
for some of their services
And there are many more here

14. Throw all?
Throw all other and use
NodeJS? NO!
NodeJS is good to handle
many request.
But will not perform well
when we need more CPU
Suitable for real-time
applications
Chat, online games ,
collaboration tools etc.

15. Question?