then chaining

A later .then receives the wrong value, an error appears in a surprising place, or a batch fails differently than expected. Data pipelines often parse, map, and render through promise chains.

Forgetting that promise chains transform values step by step.

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: 2. 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.