Challenge 1 — Solution

Task: Write the contents of a file shapes.js with two named exports:
a function circleArea(radius) and a constant TAX_RATE = 0.2. Then
write the contents of main.js that imports both and logs
circleArea(5) and TAX_RATE.

// shapes.js
export function circleArea(radius) {
    return 3.14159 * radius ** 2;
}

export const TAX_RATE = 0.2;


// main.js
import { circleArea, TAX_RATE } from './shapes.js';

console.log(circleArea(5));
console.log(TAX_RATE);


Expected output:

78.53975
0.2


Notes:
- Both circleArea and TAX_RATE are named exports — there's no limit
  on how many a single file can have, and each is imported by its
  exact name inside the braces.
- The import statement's braces work like object destructuring
  (Intermediate Chapter 1) — only the names listed are pulled into
  main.js, in this case both of shapes.js's exports.
- This only runs correctly when main.js is loaded via
  <script type="module" src="main.js"> over a real server — opening
  the HTML file directly from disk would fail.