🌐 Introduction to Node.js and npm

Node.js is a runtime environment that allows you to run JavaScript code outside the browser — commonly used for building backend services, command-line tools, and more. npm (Node Package Manager) is its companion tool used to manage libraries and dependencies.

⚙️ What is Node.js?

Node.js is built on the V8 JavaScript engine (the same engine used in Chrome) and allows developers to use JavaScript for server-side scripting.

• Runs JavaScript on the server
• Handles file systems, databases, HTTP, etc.
• Event-driven and non-blocking (asynchronous) architecture

// hello.js
console.log("Hello from Node.js!");

To run this file:

node hello.js

📦 What is npm?

npm is the default package manager for Node.js. It helps you install and manage external packages (libraries), dependencies, and scripts.

• Install packages: npm install axios
• Run custom scripts: npm run start
• Manages your project with package.json

🛠️ Installing Node.js & npm

1. Go to https://nodejs.org
2. Download the LTS version
3. Run the installer (npm is included)
4. Verify installation:

   node -v
   npm -v

🧪 Creating Your First npm Project

mkdir my-app
cd my-app
npm init -y

This creates a package.json file — a manifest that stores your project's metadata and dependencies.

📁 Installing a Package

Example: Install axios for making HTTP requests:

npm install axios

This adds a node_modules folder and updates package.json.

🔁 Running a Script

Add this to your package.json:

{
  "scripts": {
    "start": "node index.js"
  }
}

Then run:

npm start