Node.js uses JavaScript - a language known to millions of developers worldwide - thus giving it a much lower learning curve even for complete beginners. Using Node.js you can build simple Command Line programs or complex enterprise level web applications with equal ease. Node.js is an event-driven, server-side, asynchronous development platform with lightning speed execution. It is open source and cross-platform, running on OS X, Linux and Windows. It also has an open source community that produces amazing modules available for use in your project for additional functionalities. Node.js helps you to code the most complex functionalities in just a few lines of code.

1. www.edureka.co/mastering-node-js
View Mastering Node.js course details at www.edureka.co/mastering-node-js
Node JS Express - Steps to create Restful Web App

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LIVE Online Class
Class Recording in LMS
24/7 Post Class Support
Module Wise Quiz
Project Work
Verifiable Certificate
Course Features

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Objectives
At the end of the session you will be able to learn:
NPM
Node.js Express
Templates in Express
Creating Restful Web App

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What is Node.js ?
Node.js is an open source, cross-platform runtime environment for 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, Linux, FreeBSD, NonStop and IBM. -- Wikipedia
This is based on Google’s V8 JavaScript Engine

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What is Node.js ? (Contd.)
Guess What ?
» IT’s SINGLE THREADED !!
» No worries about : race conditions, deadlocks and other problems that go with multi-threading.
» “Almost no function in Node directly performs I/O, so the process never blocks. Because nothing blocks,
less-than-expert programmers are able to develop scalable systems.” - (courtesy : nodejs.org)
Event
Loop
Event
Queue
Thread Pool
file system
network
process
other

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Basics of Node.js : npm
npm used to stand for Node Package Manager. However it is not an acronym anymore. npm is not a Node.js
specific tool
npm is a registry of reusable modules and packages written by various developers
» Yes, you can publish your own npm packages
There are two ways to install npm packages :
» Locally : To use and depend on the package from your own module or project
» Globally: To use across the system, like a command line tool

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Use-Cases of Node.js
1. Walmart executives believe that the benefit of using Node.js was
far greater than any risk in adopting a new technology
2. They re-engineered their mobile app to run on Node.js where all
the front end code gets executed on back-end
3. “We rely on services all over the world,” says Almaer (V.P Mobile
Architecture) “We do not control all of those services. Node
allows us to front all these services… and scale up very nicely.
It’s perfect for what we’re doing in mobile.”
Server Side Web Applications
1. Server Side Web Applications
Advantages

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Use-Cases of Node.js (Contd.)
1. Linkedin is also leaning heavily on Node.js (Linkedin mobile and
tablet app is 95% html/web based)
2. “We’re still full-on Node. We are excited that it can scale,” says
Kiran Prasad (Head of Linkedin’s Mobile Development Team).
“Over the past few months, we’ve made performance tweaks so
we can scale even more. On four boxes, we can now handle 20
times the load we were handling before.”
Highly Scalable
1. Server Side Web Applications
2. Highly Scalable
Advantages

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Use-Cases of Node.js (Contd.)
1. When he first built Voxer, Matt Ranney (Voxer’s CTO) ran a test
to see how many connections he could open on a single server.
"I just decided to open as many connections as I could, just to
see where things would fall down," Ranney says
2. "With Node, I could open, well, all of them. I couldn't open any
more connections without getting more IP addresses on my test
machine. Node uses such small amounts of memory, it's
astounding. I ran out of port numbers."
Low Memory Consumption
1. Server Side Web Applications
2. Highly Scalable
3. Low Memory Consumption
Advantages

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Express JS
Express JS : Web Framework for Node.js. It is an npm package
To install : npm install -g express //in the main project folder
Express JS also provides a tool to create a simple folder structure for your app :
» Now, saying express newapp will create a project called newapp in the current working directory along
with a simple folder structure.
» The dependencies will then be installed by doing a cd newapp and then npm install
» To run the app
» node app // This is where the server is run and listening on a port

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Express JS : Templates
By default Express supports the Jade Template Engine for the HTML Views.
What is an Javascript Template Engine : it is a framework to help bind data to your HTML views
Why do you need one ?
» Helps you easily bind data from the back end with the HTML view
» Helps in bundling HTML code into reusable modules/layouts
» Adds basic conditionals & iterations / loops to your HTML. HTML does not support “If -Else” or “for”
loops.
Many Javascript Template Engines are available : Jade, Handlebars, Hogan, EJS, etc.

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Express JS : Jade
Jade is a simple Javascript Template engine for writing HTML. No config has to be set up for ExpressJS
since it is the default view engine
 It supports dynamic code, template inheritance and allows you to compile templates into reusable
functions that can run on server
Example of Jade syntax :
JADE
html
head
title My App Title
body
h1= pageHeaderVar
div.className
p.
some
content
HTML
<html>
<head>
<title> My App Title
</title>
</head>
<body>
<h1>Page Header</h1>
<div class=”className”>
<p>
some
content
</p>
</div>
</body>
</html>

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Express JS : A Simple Express Application
var express = require(‘express’);
var app = express();
app.get(‘/’,function(req,res){
res.send(‘Hello World !!”);
})
app.listen(3000,function(){
console.log(‘Express Server listening on port 3000);
})

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Job Trends
Salaries for Node.js Developers are already in the $60,000 range and much more.
From the graph below : The number of jobs are skyrocketing.

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DEMO

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Course Topics
→ Module 7
» Forks, Spawns and the Process Module
→ Module 8
» Testing in Node.js
→ Module 9
» Node.js in the Tech World
→ Module 1
» Introduction to Objects in Javascript & Node.js
→ Module 2
» Modules / Packages
→ Module 3
» Events & Streams
→ Module 4
» Network Communication & Web Technology in
Node.js
→ Module 5
» Building a Web Application
→ Module 6
» Real-time Communication

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Questions

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