The key output order is AB. `Promise.all` preserves input order in its result array.
A later .then receives the wrong value, an error appears in a surprising place, or a batch fails differently than expected. Use it when independent requests must all finish before rendering.
Thinking result order follows completion timing.
Return or await the promise chain so values and failures move through the flow intentionally.
return doWork() .then((value) => nextStep(value)) .catch(handleError);
The console lane proves the visible order: AB. The active line and queues show why source order changed.
Write a focused unit test that asserts the resolved value or rejected path, then verify every branch returns or awaits its work.
Related cases
Continue with nearby confusion while the mental model is fresh.
Was this clear?
This stays local for now. It helps you track where the product still needs sharper cases.