This document provides an overview of Node.js including its history, key features, and common questions. Node.js is a JavaScript runtime environment for building server-side and networking applications. It is based on Google's V8 JavaScript engine and uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, especially for real-time applications that require high throughput and scalability. The Node.js package ecosystem and large developer community help make it a full-stack JavaScript platform for building fast and scalable network applications.

1. Ansuman Roy

2. Agenda
 Introduction
 History
 Why Node.js
 Community
 Features
 FAQ
 Few Awesome Modules!
 Conclusion
get ready to node, this session is
hands on!

4. Introduction
 It’s NOT a web framework, and it’s also NOT a language
 Open Source, cross-platform runtime environment for
server-side and networking applications
 Based on Google V8 Engine Asynchronous i/o framework
 Core in c++ on top of v8
 Rest of it in javascript
 Swiss army knife for network Related stuffs
 Can handle thousands of Concurrent connections with
Minimal overhead (cpu/memory) on a single process

5.  Licence MIT
 Last release : v7.2.1
 385,151 + npm modules

6. History
 Initial Release May 27, 2009
 Created by Ryan Dahl
 Development && maintenance sponsored by Joyent

7. Is Node JS a serious option for enterprise
applications?
In fact, it’s our
best option for
typical (heavy
data IO) web
applications!
Let’s see why…

8. Why Node?
 Less keystrokes with JS
 JS on server and client allows
for more code reuse
 A lite stack (quick create-test
cycle)
 1 Language for Frontend and
Backend
 Large number of offerings for
web app creation
 Active community
Build Fast!

9. Why Node?
 Fast V8 Engine
 Single Thread with Event
Loop
 Great I/O performance
with event loop!
 Small number of layers
 Horizontal Scaling
Run Fast!

10. Why Node?
 JS across stack allows
easier refactoring
 Smaller codebase
 Cross platform( Windows,
Linux, Mac)
 See #1 (Build Fast!)
Adapt Fast!
“There’s a shift in enterprise IT,
unbundling the monolith software
packages [at many companies] that

11. Community
 Over 8 billion downloads per month
 NPM averages 461 new modules per day (ruby gems
37 per day, maven 156 per day)
 Total Number of npm Packages: 105,109
 Second most stared project on Github
 Plus, corporate backing from Joyent

12. Community
Reference : http://www.modulecounts.com/

13. Community

14. Running Node Apps
Hands On #1 – ‘Welcome Noder!’

15. Node Globals
process – object providing information and methods
for the current process
➢ process.stdout, process.stderr, process.stdin,
process.argv, process.env
 console – allows printing to stdout and stderr
 require() – function to load a module
 module – refers to the current module

16. Modules
 Modules allow Node to be extended (act as libaries)
 We can include a module with the global require
function, require(‘module’)
 Node provides core modules that can be included by
their name:
 File System – require(‘fs’)
 Http – require(‘http’)
 Utilities – require(‘util’)

17. Modules
 We can also break our application up into modules
and require them using a file path:
 ‘/’ (absolute path), ‘./’ and ‘../’ (relative to calling file)
 Any valid type can be exported from a module by
assigning it to module.exports

18. Modules
bar.js
module.exports = ‘I am a string’
foo.js
var msg = require(‘./bar.js’)
console.log(msg) // prints ‘I am a string’

19. Modules
bar.js
module.exports.hello = function() {return ‘hello’}
module.exports.bye = function() {return ‘bye’}
foo.js
var bar = require(‘./bar.js’)
console.log(bar.hello()) // prints ‘hello’
console.log(bar.bye()) // prints ‘bye’

20. Requiring Modules, File System, Args
Hands On #2 – ‘Require It’

21. Node Architecture
V8
Thread
Pool
(libeio)
Event
Loop
(libev)
Node Bindings
(socket, http, etc.)
Node Standard Library
C
C++
JavaScript

22. Node Architecture
 Node handles requests with a single thread (the
event loop)!

23. Node Architecture
 How can this be faster?
 Expensive I/O is moved off request thread (in
traditional multi-threaded environments, each thread
handles the complete request)
 Threads are limited by RAM and are expensive to create
 Avoids context switching
 Allows us to easily write asynchronous code without
heavy thread management (synchronization,
message passing, etc.)

24. Node Architecture

25. Node Architecture
Warning! Be careful to keep
CPU intensive operations off
the event loop.

26. Http and Streams
Hands On #3 – ‘Real Time Data Flow’

27. NPM
 Modules can be shared by packaging
 Node Package Manager (NPM) is a package manager
for node
 Command line interface
 Public registry www.npmjs.org
 Allows us to install packages from repo, and publish our
own

28. NPM
 First, we need to create a package.json file for our
app
 Contains metadata for our app and lists the
dependencies
 Package.json Interactive Guide

29. NPM
 Common npm commands:
 npm init initialize a package.json file
 npm install <package name> -g install a package, if –g option is
given package will be installed as a global, --save and --save-dev will add package
to your dependencies
 npm install install packages listed in package.json
 npm ls –g listed local packages (without –g) or global packages (with –g)
 npm update <package name> update a package

30. NPM
 SemVar Versions (version [Major].[Minor].[Patch]):
 = (default), >, <, >=, <=
 * most recent version
 1.2.3 – 2.3.4 version greater than 1.2.3 and less than 2.3.4
 ~1.2.3 most recent patch version greater than or equal to 1.2.3 (>=1.2.3 <1.3.0)
 ^1.2.3 most recent minor version greater than or equal to 1.2.3 (>=1.2.3 <2.0.0)

31. Http and Express
Hands On #4 – ‘Services’

32. FAQ
 V8 engine performs just as good, if not better than jvm
 Most ‘intensive’ code is usually due to I/O
 If needed, child processes, web workers, and so forth can be used
○ Of course! As always, be aware of language holes (like ‘eval’)
○ Node Security Project lists vulnerabilities in packages
What about CPU intensive code?
Is Node secure?

33. FAQ
○ Most ‘cryptic’ code is DOM related (ex. selectors)
○ Preprocessors and ECMAScript 6 bringing more strict typing (and
compile time checking)
○ As always, need standards and best practices!
What about code
readability/maintenance with JavaScript?

34. FAQ
○ Built-in Node debugger not great, but IDEs and other tools have the
usual debugging experience
○ V. 0.12 will improve tracing capabilities to allow better performance
monitoring, and production grade tools such as New Relic
Isn’t debugging and production
monitoring bad?

35. Other Awesome Modules
 skipper-gridfs – A skipper adapter to allow uploading
files to MongoDB's GridFS
 async – higher order functions and common patterns for
asynchronous code
 fs-extra– fs-extra contains methods that aren't included
in the vanilla Node.js fs package. Such as mkdir -p, cp -r,
and rm -rf
 request – Simplified HTTP request client
 mongoose – MongoDB ODM

36. Other Awesome Modules
 sails– API-driven framework for building realtime apps,
using MVC conventions (based on Express and Socket.io)
 express – Fast, unopinionated, minimalist web
framework
 jsreport– javascript based business reporting
 config – runtime configuration
 xls-to-json – Converting xls file to json files using nodejs

37. Thanks!
http://nodejs.org/
https://www.npmjs.com/
Learn More at