Modules — import/export & What to Learn Next

ES6 modules split code into files with explicit import and export. React, Vue, and modern Node.js all use this system. This is the last core ES6+ topic before you teach Node or React.

Named exports

// utils/math.js
export function add(a, b) { return a + b; }
export const TAX_RATE = 0.18;

// checkout.js
import { add, TAX_RATE } from './utils/math.js';
const total = add(100, 100 * TAX_RATE);

Default export

// services/api.js
export default async function fetchCourses() {
  const res = await fetch('/api/courses');
  return res.json();
}

// app.js
import fetchCourses from './services/api.js';

Re-export & import all

import * as MathUtils from './utils/math.js';
MathUtils.add(2, 3);

// format.js
export function formatPrice(inr) {
  return `₹${inr.toLocaleString('en-IN')}`;
}

// catalog.js
import { formatPrice } from './format.js';

export function showEbook(ebook) {
  return `${ebook.title} — ${formatPrice(ebook.price)}`;
}

Bonus — modern syntax you will see

// Optional chaining — safe deep access
const city = user?.address?.city;

// Nullish coalescing — default only for null/undefined
const theme = settings.theme ?? 'dark';

// Logical assignment
user.role ||= 'student';

What to learn next on Toolliyo

1. Review this course — practice each lesson in console
2. Build a Real-Time Chat App with Node.js — uses async, modules, arrow functions
3. Node.js Tutorial — full backend path
4. React Tutorial — components + hooks (needs ES6 first)

Course recap checklist

• ✅ let / const and block scope
• ✅ Arrow functions and array methods
• ✅ Template literals, destructuring, spread/rest
• ✅ Promises and async/await
• ✅ import / export modules