The document provides an overview of Node.js, highlighting its features, architecture, core modules, and the steps for installation and creating a basic application. Node.js is described as an asynchronous, event-driven runtime environment built on Chrome's V8 engine that allows for scalable application development. It covers key aspects such as the event loop, thread pool, and core modules like 'http', 'url', and 'fs', along with practical guidance for setup and creating a simple Node.js server.

1. WEEKLY PRESENTATION
DURING TRAINING PROGRAM
- Devang Garach
devanggarach.rao@gmail.com
WEEK-7
Information Technology

2. AGENDA - Fundamental of Node.JS
What is Node.JS
Features of Node.JS
Node.JS Architecture
Core modules in Node.JS
Node.JS Installation
npm
Creating first node.js application
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3. What is Node.JS
Node.js is an open-source, back-end JavaScript runtime server environment.
It uses Google Chrome V8 engine and executes code.
It is cross platform environment and can run on OS X, Microsoft Windows,
Linux,...
Provides an event driven architecture and non blocking I/O that is optimized
and scalable.
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4. Features of Node.JS
Asynchronous:
When request is made to server, instead of waiting for the request to
complete, server continues to process other requests.
When request processing completes, the response is sent to caller using
callback mechanism.
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Caller Recipient
Request
Response
Callback
Asynchronous Model

5. Features of Node.JS (Continue...)
Single Thread and Event Driven:
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Event Emitters
Event Queue
File System
Network
Process
Other
Event Loop
(Single - Threaded)

6. Features of Node.JS (Continue...)
Very Fast:
Being built on Google Chrome's V8 JavaScript Engine, Node.JS library is
very fast in code execution.
Single Threaded, but very highly scalable
Node.js highly scalable because event mechanism helps the server to
respond in non-blocking way
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7. Node.JS Architecture
Requests
Incoming requests can be blocking (complex) or
non-blocking (simple), depending upon the tasks
that a user wants to perform in a web application
Node.js Server
Node.js server is a server-side platform that takes
requests from users, processes those requests,
and returns responses to the corresponding users.
Event Queue
Event Queue in a Node.js server stores incoming
client requests and passes those requests
one-by-one into the Event Loop
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8. Node.JS Architecture (Continue...)
Thread Pool
Thread pool consists of all the threads available for
carrying out some tasks that might be required to
fulfill client requests
Event Loop
Event Loop indefinitely receives requests and
processes them, and then returns the responses to
corresponding clients
External Resources
External resources are required to deal with blocking
client requests. These resources can be for
computation, data storage, etc.
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9. Core modules in Node.JS
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Core
Module Description
http http module includes classes, methods and events to create Node.js http server.
url url module includes methods for URL resolution and parsing.
querystring querystring module includes methods to deal with query string.
path path module includes methods to deal with file paths.
fs fs module includes classes, methods, and events to work with file I/O.
util util module includes utility functions useful for programmers.

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1. Download from official
website node.org/download
2. Install it in your compatible
OS
3. After installation,
check installation version
> node --v
Installation

11. Information Technology
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Node Package Manager
A package in Node.js contains all
the files you need for a module.
Modules are JavaScript libraries
you can include in your project.
Downloading a package is very
easy. Open the command line
interface and tell NPM to
download the package you want.
> npm install express
We first have to use npm init , it
create package.jsonfile
npm

12. Creating first node.js program
1. Importing Module:
“require” is used to load a node.js modules
2. Creating Server:
Used to create web server object
Function (request,response) is called once
for every HTTP request to the server, so it’s
called the request handler
3. listen(<port_no>):
Bind the server instance for listening to a
particular port.
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var http = require(“http”);
var server = http.createServer(
function(request, response){
console.log(‘creating server object’);
}
);
server.listen(port,function(
){
console.log(‘server running
at http://localhost:3000 ’)
}
);

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To run node.js program
> node <nodejs_file>
Creating first node.js program (Continue...)

14. Thank You.
- Devang Garach
devanggarach.rao@gmail.com
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