Challenge 1 — Solution

Task: Write a generator function* evens(max) that yields every even
number from 0 up to max (inclusive). Use for...of to print every
value it produces for evens(10).

function* evens(max) {
    for (let i = 0; i <= max; i += 2) {
        yield i;
    }
}

for (const n of evens(10)) {
    console.log(n);
}


Expected output:

0
2
4
6
8
10


Notes:
- i += 2 in the loop's post clause steps by 2 each time, the same
  technique used in Go Fundamentals Chapter 4's equivalent even-number
  challenge, just written here with JavaScript's for loop.
- for...of works directly on evens(10) because calling a generator
  function automatically returns something that already satisfies
  the iterator protocol — no .next() calls were written explicitly.
- evens(10) is finite (the loop condition i <= max guarantees it
  eventually stops), which is exactly why for...of is safe to use
  here, unlike with an infinite generator.