[2026] Getting Started with Node.js: Install, Setup, and Hello World

Introduction

What is Node.js?

Node.js is a JavaScript runtime built on Chrome’s V8 engine. It lets you run JavaScript outside the browser. Key characteristics:

• Non-blocking I/O: High throughput for I/O-heavy workloads
• Single-threaded model: Event loop–driven concurrency
• Cross-platform: Windows, macOS, and Linux
• npm: The world’s largest package ecosystem
• One language: Share JavaScript between frontend and backend Good fits for Node.js:
• REST and JSON APIs
• Real-time apps (chat, games, collaboration)
• Microservices and BFF layers
• CLI tools and build scripts
• Streaming and upload pipelines Poor fits:
• CPU-heavy work (image/video transcoding, large numerical jobs)
• Work that needs true parallel CPU crunching (use workers, native addons, or another runtime)

---

1. Node.js vs browser JavaScript

Aspect	Browser JavaScript	Node.js
Environment	Browser (Chrome, Firefox, …)	Server, local machine
Global	window	global
DOM	Yes	No
File system	No	Yes (fs)
HTTP server	No (without bundling/workarounds)	Yes (http, https)
Modules	ES Modules (modern)	CommonJS + ES Modules
Package manager	None built-in	npm, yarn, pnpm

Shared JavaScript APIs

아래 코드는 javascript를 사용한 구현 예제입니다. 비동기 처리를 통해 효율적으로 작업을 수행합니다. 각 부분의 역할을 이해하면서 코드를 살펴보시기 바랍니다.

console.log("Hello");
setTimeout(() => console.log("After 1s"), 1000);
setInterval(() => console.log("Tick"), 1000);
const fetchData = async () => {
    const result = await Promise.resolve("data");
    return result;
};
const obj = JSON.parse('{"name": "Alice"}');
const str = JSON.stringify({ name: "Alice" });

Node-only APIs

아래 코드는 javascript를 사용한 구현 예제입니다. 각 부분의 역할을 이해하면서 코드를 살펴보시기 바랍니다.

const fs = require('fs');
const content = fs.readFileSync('file.txt', 'utf8');
const http = require('http');
const server = http.createServer((req, res) => res.end('Hello'));
const path = require('path');
const filePath = path.join(__dirname, 'file.txt');
console.log(process.version, process.platform, process.cwd(), process.pid);

Prefer async fs methods on servers; sync calls block the event loop.

2. Installing Node.js

Windows

1. nodejs.org → download LTS
2. Run the installer
3. Verify: node --version, npm --version

macOS

Official installer or brew install node.

Linux (Ubuntu/Debian example)

curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
sudo apt-get install -y nodejs

nvm

curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.0/install.sh | bash
nvm install 20
nvm use 20

---

3. First programs

Hello World

console.log("Hello, Node.js!");
console.log(`Node ${process.version}, platform ${process.platform}`);

CLI arguments

아래 코드는 javascript를 사용한 구현 예제입니다. 조건문으로 분기 처리를 수행합니다. 코드를 직접 실행해보면서 동작을 확인해보세요.

console.log(process.argv);
const args = process.argv.slice(2);
if (args.length === 0) {
    console.log("Usage: node args.js <name>");
    process.exit(1);
}
console.log(`Hello, ${args[0]}!`);

Environment variables

const port = process.env.PORT || 3000;
const nodeEnv = process.env.NODE_ENV || 'development';
console.log(port, nodeEnv);

---

4. First HTTP server

아래 코드는 javascript를 사용한 구현 예제입니다. 각 부분의 역할을 이해하면서 코드를 살펴보시기 바랍니다.

const http = require('http');
const server = http.createServer((req, res) => {
    console.log(`${req.method} ${req.url}`);
    res.writeHead(200, { 'Content-Type': 'text/plain; charset=utf-8' });
    res.end('Hello from Node.js!');
});
const PORT = 3000;
server.listen(PORT, () => console.log(`http://localhost:${PORT}`));

Add routing by branching on req.url and req.method; return JSON with JSON.stringify and Content-Type: application/json.

5. npm

npm init -y
npm install express
npm install --save-dev nodemon

아래 코드는 json를 사용한 구현 예제입니다. 코드를 직접 실행해보면서 동작을 확인해보세요.

{
  "scripts": {
    "start": "node index.js",
    "dev": "nodemon index.js"
  }
}

---

6. Modules

CommonJS: module.exports / require. ES modules: "type": "module" in package.json, then import / export. Same patterns as the modules article.

7. File system (fs)

Sync (readFileSync), callback (readFile), and Promise (require('fs').promises) styles exist—use Promises + async/await for server code.

8. Examples

Minimal multi-route server, static file server, and CLI directory counter—see the filesystem guide for full listings.

9. nodemon

npm install --save-dev nodemon

{ "scripts": { "dev": "nodemon server.js" } }

---

10. Debugging

VS Code launch.json with "type": "node", or node inspect script.js.

11. dotenv

npm install dotenv

Load secrets from .env; never commit .env (list in .gitignore).

12. Common issues

• EADDRINUSE — port busy; pick another port or kill the process
• Cannot find module — run npm install
• Wrong path — use path.join(__dirname, ...)
• Async mistakes — use await / .catch() consistently

---

13. Tips

Typical layout: src/ (routes, controllers, utils), public/, tests/, .env, package.json. Handle uncaughtException, unhandledRejection, and graceful shutdown on SIGTERM. Use streams for large files; consider cluster for CPU-bound scaling.

Summary

Node.js is the V8-based JavaScript runtime for servers and tools. Install LTS, use npm, prefer async fs and HTTP APIs for services, and move on to modules and Express.

Next steps

• Node.js module system
• Async programming
• Express.js

Resources

• Node.js docs
• npm docs

---

Related posts

• Node.js series
• JavaScript introduction
• Modules: CommonJS and ES modules