Backend 01 - Node.js Basics

1. What is Node.js?

• A JavaScript runtime environment.

• Allows running JavaScript outside the browser (e.g., on servers).

• Built on Chrome’s V8 JavaScript Engine.

• Enables building fast, scalable network applications.

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2. Who Created Node.js and Why?

• Created by: Ryan Dahl

• Released in: 2009 (initial work started in 2007)

• Reason:

  • Traditional servers like Apache handled concurrent requests inefficiently.

  • Node.js was designed for non-blocking, event-driven, real-time applications.

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3. Installing Node.js

• Download from https://nodejs.org

• Choose:

  • LTS (Long Term Support): Stable version recommended for most users.

  • Current: Latest features but less stable.

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4. Running JavaScript Files with Node

• Use the terminal/command prompt:

    node filename.js
  

• Node provides its own runtime environment with built-in APIs like:

  • fs (file system)

  • http (server creation)

  • path, etc.

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5. Packages in Node.js

• Packages are reusable libraries or tools.

• Installed using npm (Node Package Manager).

• Example:

    npm install cat-me
  

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6. Packages vs Modules

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7. Installing and Using a Package (e.g., cat-me)

• Installation:

    npm install cat-me
  

• Usage in your code:

    const catMe = require("cat-me");
    console.log(catMe());
  

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8. HTTP Module in Node.js

• Built-in module to create servers.

• No installation required.

• Enables handling HTTP requests and responses.

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9. Creating a Simple Server with HTTP Module

// http -> it is a module. didn't require to install
//express -> it is a package. reuired to install 

const http = require('http')

const server = http.createServer((req,res)=>{
      res.end("Hello! Code Subtle") //printing message to server
}) //for creating the server


//for starting the server
server.listen(3000,()=>{
      console.log("server is running");
})