Apple·Frontend Engineer·Technical Phone Screen
- How does React 18's concurrent rendering work, and what problems is it actually solving?
- Walk me through useTransition. When would you use it and what are the tradeoffs?
- What's the difference between useTransition and useDeferredValue, and when would you reach for one over the other?
- What is useId for and why does it matter for server-side rendering?
- Explain useSyncExternalStore and why it exists specifically for concurrent mode.
“I started with the scheduler and interruptible rendering model, which felt right, but I fumbled explaining why it matters in practice.”