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How do you import a module in Node.js?

 In Node.js, you can import modules using either the CommonJS syntax or the ES Module (ESM) syntax, depending on your project setup.


✅ 1. CommonJS (Default in Node.js)

Most Node.js projects use CommonJS by default.

// Importing a built-in module
const fs = require('fs');

// Importing a third-party module
const express = require('express');

// Importing your own module
const myModule = require('./myModule');

  • Works out of the box in .js files.

  • Used widely in older Node.js codebases.

✅ 2. ES Modules (ECMAScript Modules)

If your project uses "type": "module" in package.json or your file has a .mjs extension, you can use ESM syntax:

js

// Importing a built-in or third-party module
import fs from 'fs';
import express from 'express';

// Importing your own module
import myModule from './myModule.js';


⚠️ Note: Relative imports in ESM must include the file extension (.js, .mjs, etc.).

When to Use Which?

Project TypeUse
Traditional Node.jsrequire()
Modern, ESM-basedimport
Bundled front-end appsimport (via tools like Webpack, Vite)

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