ES6 Module

        
          // Exporting (in math.js)
// Named exports
export const PI = 3.14159;
export function add(a, b) {
  return a + b;
}

// Default export
export default class Calculator {
  multiply(a, b) {
    return a * b;
  }
}

// Importing
import { PI, add } from './math.js';
import Calculator from './math.js';

// Or import everything
import * as MathUtils from './math.js';

// Usage
console.log(PI); // 3.14159
console.log(add(2, 3)); // 5

const calc = new Calculator();
console.log(calc.multiply(4, 5)); // 20

// Dynamic imports
const module = await import('./math.js');
console.log(module.PI);