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Demo 17

await behavior

`await` pauses the async function and resumes it in a microtask.

fully simulatedcurated scenariodoes not execute real code
Short answer

The key output order is A -> C -> B. `await` yields control even when the promise is already resolved.

Real-world bug this helps solve

The UI, test, redirect, or log moves forward before the async result is actually ready. Await points can let other code observe intermediate state.

Common wrong assumption

Thinking `await Promise.resolve()` continues synchronously.

Fix direction

Await real dependencies, start independent work together, and choose the loop pattern that matches the behavior you need.

Fixed code pattern
const [user, posts] = await Promise.all([
  fetchUser(),
  fetchPosts()
]);
Visual proof

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

How to verify in a real app

Measure before and after with logs or test spies: the dependent line should run only after the awaited operation finishes.

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Related cases

Continue with nearby confusion while the mental model is fresh.

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