Node.js

Welcome to Node.js. If you know a little JavaScript in the browser, you are already halfway there — we just run it on your computer instead of Chrome.

What you will learn

• What node.js means — in normal words, not textbook words
• How it works step by step
• Code you can run today on your laptop
• Where teams use this in real projects

Before you start

• Software: Node.js LTS from nodejs.org, VS Code, and a terminal
• Knowledge: Basic computer skills. Helpful: tiny bit of JavaScript (variables, functions) — we explain as we go.

Explain it simply

Node.js lets you run JavaScript outside the browser — on your laptop or on a server. It uses Chrome's V8 engine (the same engine that runs JavaScript in Chrome). Teams use it for APIs, real-time chat, automation scripts, and full backend apps.

Why developers use this

• One language (JavaScript) for frontend and backend
• Huge npm library ecosystem
• Great for APIs, chat, and tools that handle many users

How it works (step by step)

1. You write JavaScript in a .js file about Introduction to Node.js.
2. You run it with node filename.js in the terminal.
3. Node prints output or starts a server depending on the lesson.
4. You change one line, run again, and see what changed — that is how you learn.

Code example — type this yourself

// hello.js
console.log('Hello from Node.js!');
console.log('Node version:', process.version);

Save as hello.js. Open terminal in that folder. Run node hello.js. You should see two lines printed.

What each part does

• // hello.js — Line 1: runs as written.
• console.log('Hello from Node.js!'); — Prints to the terminal — great for learning; use proper logging in production.
• console.log('Node version:', process.version); — Prints to the terminal — great for learning; use proper logging in production.

Real life: your first backend

A freelancer builds a contact-form API for a client website. The HTML form posts to a tiny Node server that sends an email. No Java framework needed — just JavaScript they already know.

Try it yourself — hands-on

1. Install Node.js LTS from nodejs.org
2. Create a folder my-node and add hello.js
3. Run node hello.js in terminal
4. Change the message string and run again

Common mistakes (avoid these)

• Confusing Node.js with React — React is UI in the browser; Node is JavaScript on the server.

Interview note

Interviewers often ask: “What is Introduction to Node.js?” Answer in one sentence, then give a tiny example you actually ran.

Summary

• Node runs JavaScript with the node command
• You do not need a browser
• Next lessons build up to real APIs