ECMAScript Modules (MJS)

// Import
import fs from "fs"; 
import { myFunc } from "./module.js";

// Export
export default function greet() {
  console.log("Hello");
}
export const myFunc = () => "Hello World";

CommonJS (CJS)

// Import
const fs = require("fs");
const { myFunc } = require("./module");

// Export
module.exports = function greet() {
  console.log("Hello");
};
exports.myFunc = () => "Hello World";