Challenge 1 — Solution

Task: Without running it, write down (or comment) the exact
console.log order for this code, then run it to check:
console.log("1"); setTimeout(() => console.log("2"), 0);
Promise.resolve().then(() => console.log("3"));
Promise.resolve().then(() => console.log("4")); console.log("5");

console.log("1");
setTimeout(() => console.log("2"), 0);
Promise.resolve().then(() => console.log("3"));
Promise.resolve().then(() => console.log("4"));
console.log("5");


Expected output:

1
5
3
4
2

Notes:
- "1" and "5" are the only two purely synchronous console.log calls
  here, so they run first and in the order they appear in the code,
  before anything asynchronous gets a turn.
- Both .then() callbacks are microtasks, and the ENTIRE microtask
  queue drains before the next macrotask — so "3" and "4" both run,
  in the order they were queued, before "2" (the setTimeout
  macrotask) gets a chance.
- "2" runs last specifically because setTimeout schedules a
  macrotask, and macrotasks always wait for the microtask queue to
  be completely empty first, regardless of the 0ms delay.