JavaScript Modules CommonJS, EM, ES2015

CommonJS

Used in node.js

mod.js

exports.foo = () => {}

app.js

const mod = require("mod")
mod.foo()

AMD (Asynchronous Module Definition)

define(['jquery'] , function ($) {
    return function () {};
});

ES2015(ESCMA6)

foo.js

export const a = {} // `equals exports.a = {}` of CommonJS
// or 
module.exports = {a: {}}

app.js

import {a} from foo // `equals const a = require("foo").a` of CommonJS
// or
import * as foo from "foo"
const a = foo.a

refs

1. https://addyosmani.com/writing-modular-js/
2. https://auth0.com/blog/javascript-module-systems-showdown/
3. https://requirejs.org/docs/whyamd.html
4. https://2ality.com/2014/09/es6-modules-final.html