The document provides an overview of Node.js including that it is a cross-platform runtime environment for JavaScript outside the browser, uses an event-driven and non-blocking I/O model, and is perfect for data-intensive real-time applications. It discusses Node.js features like being extremely fast, asynchronous and event-driven, single-threaded, and highly scalable. The document also covers installing Node.js, using the command line interface and REPL, basic commands, data types, functions, buffers, the process object, global scope, and exporting modules.

1. Workshop
@
Ramnshee Infotech
By Jainul Musani
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1

2. SESSION:01
Node.Js
 Node.js is a cross-platform runtime environment
 Node.js provide a library to run JavaScript applications
outside the browser.
 Node.js is used for creating server-side and networking
web applications.
 It is open source and free to use.
 It can be downloaded from this
link https://nodejs.org/en/
Node.js = Runtime Environment +
JavaScript Library

3. About Node.js
 Node.js uses
 Event-Driven,
Non-Blocking I/O model
Lightweight and Efficient,
 Perfect for Data-Intensive real-time applications
Run across distributed devices
Node.js is a platform built on Chrome's JavaScript
runtime
easily building fast and scalable network
applications.
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4. Traditional Web Server Model
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5. Nodejs Process Model
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6. Different Parts of Node.js
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7. Features of Node.js
 1) Extremely fast:
 2) I/O is Asynchronous and Event Driven:
 3) Single threaded:
 4) Highly Scalable:
 5) No buffering:
 6) Open source:
 7) License: under the MIT license.
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8. Installation of Node.js
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9. Start with Node.js CLI
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 C:UsersJainul>node
Welcome to Node.js v12.17.0.
Type ".help" for more information.
> _
 > console.log("Good Morning...!!!")
Good Morning...!!!
undefined

10. Simple Commands with Node.js
 Create a .js file “node1.js”
 Write basic commands of Js and save the file.
Console.log(“Testing”);
Console.log(“Good Morning…!!!”);
 D:UsersJamtemp>node node1.js (.js is optional)
Testing
Good Morning....!!!
 D:UsersJamtemp> _
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11. Node.js REPL
 Read
 Evaluate
 Print
 Loop
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12. How to start REPL – (Nodejs CLI)
 C:UsersJainul>node
Welcome to Node.js v12.17.0.
Type ".help" for more information.
> _
 > console.log("Good Morning...!!!")
Good Morning...!!!
undefined
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13. REPL commands and Features
 Press Ctrl+C to terminate the current command.
Pressing Ctrl + C twice causes the REPL to quit.
Press Ctrl+D to exit the REPL.
 Pressing up and down arrow keys you can see command
history and modify previous commands.
 Press tab key to see the list of current commands. If you
type a single character followed by tab it will show the
list of keywords, functions, and variables starting with
that particular character.
 The REPL can handle multiline expression.
 The REPL provides a special variable _ (underscore)
which is used to pull the result of the last expression.
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14. REPL commands and Features
> 1+2
3
> 1+2-3
0
> 1+(3-2)*4/2
3
>
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15. REPL commands and Features
> var x = 10;
undefined
> var y = 20;
undefined
> x+y
30
> console.log(x+y);
30
undefined
>
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16. Node.js Underscore _ variable
 To get last result use underscore _ variable
> console.clear()
> a = 10
> b = 15
> a+b
25
> console.log(“last sum is: “ + _+5);
last sum is 30
>
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17. Node.js Loop structure ‘do-while’
 Loop Structure in
Node.js
> var a = 10
undefined
> i = 1
1
> do{
... console.log(i)
... i++;
... }while(i<a);
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>
1
2
3
4
5
6
7
8
9
>
Output:

18. Node.js Primitive Data Types
 Node.js includes following primitive types:
• String
• Number
• Boolean
• Undefined
• Null
• RegExp
 Everything else is an object in Node.js.
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19. Node.js Data Types
 Loose Typing
• JavaScript in Node.js supports loose typing like
the browser's JavaScript.
• Use var keyword to declare a variable of any
type.
• Object Literal
var obj = {
authorName: 'Raxit Dilhan',
language: 'Node.js'
}
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20. Function in NodeJs
File name: func1.js
function display(){
console.log("Function 1");
}
function dispPara(x){
console.log("Function with Para : ", x);
}
display();
dispPara(10);
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21. Buffer in NodeJs
 Node.js includes an additional data type
called Buffer (not available in browser's
JavaScript).
 Buffer is mainly used to store binary data,
while reading from a file or receiving packets
over the network.
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22. process object in NodeJs
Each Node.js script runs in a process.
It includes process object to get all the
information about the current process of
Node.js application.
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23. Defaults to local in NodeJs
Nodejs JavaScript is different from
browser's JavaScript when it comes to
global scope.
In the browser's JavaScript, variables
declared without var keyword become
global.
In Node.js, everything becomes local by
default.
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24. Access Global Scope in NodeJs
In a browser, global scope is the window
object. In Node.js, global object represents
the global scope.
To add something in global scope, you need
to export it using export or module.export.
The same way, import modules/object using
require() function to access it from the
global scope.
For example, to export an object in
Node.js, use exports.name = object.
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25. Access Global Scope in NodeJs
exports.mylib = {
 sum: function(a,b) {
 console.log(“Sum = “, a+b);
 },
 greet: function(msg) {
 console.log(“Hello…”, msg);
 }
}
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