Skip to main content

Demo 19

try/catch

A try/catch around `await` catches promise rejections.

fully simulatedcurated scenariodoes not execute real code
Short answer

The key output order is nope. `await` turns a rejected promise into a thrown value at the await point.

Real-world bug this helps solve

The UI, test, redirect, or log moves forward before the async result is actually ready. This is the normal shape for request error handling in async functions.

Common wrong assumption

Putting try/catch around the caller instead of around the awaited operation.

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: nope. 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.

Share
Loading visual timeline...

Related cases

Continue with nearby confusion while the mental model is fresh.

Recommended next

Was this clear?

This stays local for now. It helps you track where the product still needs sharper cases.

Send detail