React Holiday

#19: What have we learned this week?

This week we learned that Concurrent ‘mode’ is dead, that transitions help us improve user experience for slow views, and when to choose useTransition over startTransition.

I’d like to test your knowledge with a few questions:

  1. If there is no bottom-up “Concurrent Mode” for React, which parts of a React 18 application use concurrent rendering?
  2. What types of user experiences do transitions help us improve?
  3. What additional insight does useTransition give us that startTransition does not?
  4. What is the order of elements returned from useTransition?

If you feel like you didn’t catch everything, review all the lessons at Or re-watch this week’s video recap.

🐦 chantastic

This week is filled with new concepts.
If you’re having trouble, hit reply and let me know how I can help!


  1. The parts of a React 18 application that utilize concurrent rendernig are the component trees that use concurrent features like startTransition, useTransition, and getDeferredValue.
  2. Transitions help us improve user experience when updates are slow. Transitions are useful for both slow networks and expensive computations.
  3. A boolean with the state of the transition.
  4. [isPending <boolean>, startTransition <function>]