useSyncExternalStore Quiz

Test your knowledge of the useSyncExternalStore Hook in React, including external subscriptions, snapshots, server rendering, and store integration.

20 questions · free · answers explained

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All questions in this quiz

  1. What is useSyncExternalStore used for?
  2. Which two functions are required by useSyncExternalStore?
  3. What should the subscribe function do?
  4. What should getSnapshot return?
  5. Why must getSnapshot return a cached value when the store has not changed?
  6. What is the optional third argument to useSyncExternalStore for?
  7. What kind of source is a good fit for useSyncExternalStore?
  8. What is a common browser API example for useSyncExternalStore?
  9. When does React call getSnapshot?
  10. What should happen when the external store changes?
  11. Why is useSyncExternalStore useful for library authors?
  12. What should getSnapshot avoid doing?
  13. What happens if subscribe is defined inside a component without memoization?
  14. What does useSyncExternalStore return to the component?
  15. Which issue can useSyncExternalStore help prevent?
  16. Should useSyncExternalStore replace useState for normal local component state?
  17. What should getServerSnapshot return during hydration?
  18. Which comparison does React use for snapshot changes?
  19. What is a practical pattern for mutable external stores?
  20. What is the main responsibility of useSyncExternalStore?

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