setTimeout 0

Console output or cleanup runs in an order that does not match the source code order. Useful when you need to defer UI work until after the current event handler.

Assuming 0 means immediate.

Make ordering explicit instead of relying on when a queued callback might happen to run.

Promise.resolve().then(handleMicrotask);
setTimeout(handleTimer, 0);
// Assert/expect the microtask before the timer.

The console lane proves the visible order: A -> C -> B. The active line and queues show why source order changed.

Add temporary logs around the sync line, promise callback, and timer, then confirm the order without adding arbitrary delays.