Modules, npm, and Project Setup

CommonJS and ES Modules

Modern Node supports ES Modules with import/export. CommonJS (require/module.exports) still exists in many legacy projects.

// math.js
export function add(a, b) {
  return a + b;
}

// app.js
import { add } from "./math.js";
console.log(add(5, 7));

npm essentials

• npm init creates package metadata and scripts.
• npm install adds dependencies to package.json.
• Use scripts for repeatable commands (dev, test, lint).
• Keep dependencies updated and audited.

npm init -y
npm install express
npm install -D nodemon
npm pkg set type=module