Node.js · Chapter 4 of 43

Node.js Modules

Modules let you organize code into separate reusable files. Node.js treats every file as its own module with its own scope.

You export values from one file and import them into another, keeping large applications maintainable.

Creating a module

Use `module.exports` to expose functions, objects, or values from a file so other files can use them.

Use `require()` to import built-in, third-party, or your own modules by path or name.

Example 1 (javascript)

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

This file exports a single function using module.exports.

Example 2 (javascript)

// app.js
const add = require('./math.js');
console.log(add(2, 3));

Output

require() loads the exported function and it can be called directly.

💡 Note: Built-in modules like `fs` and `path` don't need installation, just `require()`.