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Node.js•Node.js Tutorial

Node.js Introduction

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Node.js Introduction

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What You'll Learn

In this tutorial, you'll learn: How to install and run Node.js Core concepts like modules and the event loop

How to build web servers and APIs

Working with databases and files

Deploying Node.js applications What is Node.js?

Formula

Node.js is a free, open - source JavaScript runtime that runs on Windows, Mac, Linux, and more.
It lets you execute JavaScript code outside of a web browser, enabling server - side development with JavaScript.

Built on Chrome's V8 JavaScript engine, Node.js is designed for building scalable network applications efficiently.

Example: Print a Message console.log('Hello from Node.js!'); Why Node.js? Node.js excels at handling many simultaneous connections with minimal overhead, making it perfect for:

Real-time applications

(chats, gaming, collaboration tools)

APIs and microservices

Data streaming applications

Command-line tools

Server-side web applications

Formula

Its non - blocking, event - driven architecture makes it highly efficient for I/O - heavy workloads.

Asynchronous Programming

Node.js uses asynchronous

Formula

(non - blocking) programming.

This means it can keep working while waiting for tasks like reading files or talking to a database.

Formula

With asynchronous code, Node.js can handle many things at once - making it fast and efficient.

Example: Read a File Asynchronously

// Load the filesystem module const fs = require('fs');
// Read file asynchronously fs.readFile('myfile.txt', 'utf8', (err, data) => {
if (err) {
console.error('Error reading file: ' + err);
return;
}
console.log('File content: ' + data);
});
console.log('Reading file... (this runs first!)');

In this example:

We load the built-in fs module

We call readFile to read a file

Node.js continues to the next line while reading the file When the file is read, our callback function runs

Formula

This non - blocking behavior lets Node.js handle many requests efficiently.

What Can Node.js Do?

Web Servers

: Create fast, scalable network applications

File Operations

: Read, write, and manage files on the server

Database Interaction

: Work with databases like MongoDB, MySQL, and more

APIs

: Build RESTful services and GraphQL APIs

Real-time

: Handle WebSockets for live applications

CLI Tools

Formula

: Create command - line applications

Example: Simple Web Server const http = require('http');

http.createServer((req, res) => {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello World!');
}).listen(8080);

What is a Node.js File? Node.js files contain code that runs on the server. They usually have the.js extension and can be started with the node command. Node.js files run tasks when certain events happen (like a web request) They must be started on the server to have any effect

They use JavaScript syntax

Example: Running a Node.js File node app.js Node.js Versions & LTS: Node.js releases a new major version every six months. For stability, use an LTS (Long Term Support) version for production projects.

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