What is npm?

npm (Node Package Manager) is the world's largest software registry and the default package manager for Node.js. It allows developers to share and reuse code, making JavaScript development faster and more efficient.

Why npm Matters

npm solves a fundamental problem in software development: code reuse. Instead of writing everything from scratch, you can:

• Install packages - Use pre-built solutions for common tasks
• Share code - Publish your own packages for others to use
• Manage dependencies - Keep track of what your project needs
• Automate tasks - Run scripts for building, testing, and deploying

The npm Ecosystem

npm consists of three main parts:

1. The Registry

The npm registry is a massive database of JavaScript packages. With over 2 million packages, it's the largest software registry in the world. Anyone can publish packages, and anyone can install them.

2. The CLI (Command Line Interface)

The npm command is what you use in your terminal to interact with the registry:

npm install lodash    # Install a package
npm publish           # Publish your package
npm search react      # Search for packages

3. The Website

npmjs.com lets you:

• Browse and search packages
• View documentation and usage stats
• Manage your published packages

npm vs Node.js

It's important to understand the relationship:

Concept	Description
Node.js	A JavaScript runtime that lets you run JS outside the browser
npm	A package manager that comes bundled with Node.js

When you install Node.js, you automatically get npm. They work together but serve different purposes.

Real-World Example

Imagine you need to format dates in your JavaScript application. Without npm, you might:

1. Research date formatting algorithms
2. Write hundreds of lines of code
3. Handle edge cases and timezones
4. Test thoroughly

With npm, you simply:

npm install date-fns

Now you have access to a battle-tested library used by thousands of developers:

import { format } from 'date-fns';

format(new Date(), 'MMMM do, yyyy');
// → "January 10th, 2026"

Practice: Explore package.json

Here's an example package.json file. This is the heart of every npm project:

Key Takeaways

1. npm is essential - Nearly every JavaScript project uses it
2. Massive ecosystem - Over 2 million packages available
3. Saves time - Reuse code instead of reinventing the wheel
4. Built into Node.js - Comes pre-installed with Node.js

What's Next?

In the next lesson, you'll learn how to install Node.js and npm on your system, and verify that everything is working correctly.