Why this exists
JavaScript runtime confusion should not stay invisible.
JS Clarity Lab exists for the moment when a developer sees weird output, a late timer, an early success message, a slow API, or growing memory and needs a clear visual answer fast.
Developers do not need more vague async theory
They need to see why their actual output happened and what to change next.
Prediction creates real understanding
When users predict first, the visual result exposes the exact mental model gap.
Runtime behavior should be visible
Queues, timers, promises, streams, thread pool work, and memory retention become easier when users can inspect the moving parts.
Trust matters more than magic
The analyzer is honest: fully simulated, partially simulated, detected only, or unsupported. It never executes pasted code.
The product promise
Change the situation, predict the result, see the timeline, and understand why it happened.