Modern JavaScript – ES6 Modules

Modules allow you to split code into reusable files.

• Export – export const foo = 1; or export default function(){}.
• Import – import {foo} from './module.js'; or import MyClass from './MyClass.js';.
• Browsers support native modules via <script type="module">.

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Example: Two‑file module system

file: utils.js

export function sum(a,b){ return a+b; }
export const PI = 3.1415;

file: app.js

import {sum, PI} from './utils.js';
console.log(sum(2,3), PI);

HTML

<script type="module" src="app.js"></script>