Separating the Urgent from the Non-Urgent

Hands-on practice for this lecture. Work through the exercises and quizzes to reinforce what you've learned.

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Exercise 1 of 1

Urgent vs Non-Urgent: Seeing Lane Priority in Action

A chat input blocked by an expensive counter update — use startTransition to move the counter to a lower-priority lane so the input paints first.

Chat — all updates same priority

Your message

Type in the input. Characters appear sluggishly because the expensive tick runs at the same priority as the input update.

TypingIndicator renders: 1

Active typists: 1(expensive re-render simulated)

Test Your Understanding

Multiple choice — select an answer to see the explanation.

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By default, how does React treat concurrent state updates triggered by a user interaction?