Node.js Environment

Node.js lets you run JavaScript outside the browser — on servers, desktops, and IoT devices.

Visual Explanation

flowchart TD
    A["📄 app.js"] --> B["🖥️ Node.js"]
    B --> C["⚙️ V8 Engine"]
    C --> D["📁 File System"]
    C --> E["🌐 HTTP Module"]
    C --> F["🔌 Streams"]
    C --> G["📦 npm Packages"]

    style B fill:#059669,color:#fff
    style G fill:#cb3837,color:#fff

Installation

Go to nodejs.org
Download the LTS version
Run the installer
Verify:

node --version   # e.g., v22.x.x
npm --version    # e.g., 10.x.x

Running JavaScript with Node.js

# Run a file
node app.js

# Open the REPL (interactive shell)
node
> console.log("Hello from Node.js!")
> .exit

Example

// app.js — server-side JavaScript
const fs = require("fs");

fs.writeFileSync("hello.txt", "Hello from Node.js!");
console.log("File created!");

node app.js
# File created!
# Check your directory — hello.txt exists!