React Deep Dive: useOptimistic

Frontend First

Ryan and Sam discuss the purpose and usage of the useOptimistic() hook, a new experimental API from React.

Topics include:

• 0:00 - Intro
• 2:18 - Problem: RSCs require a server roundtrip before the UI can be updated
• 10:13 - Solution: useOptimistic() lets you merge ephemeral client-side state with server-side data so you can update the UI during a Server Action or Transition
• 14:03 - How useOptimistic() avoids the notion of identity by discarding the ephemeral state after the app settles
• 21:17 - How useOptimistic() lets you safely “fork” state that eventually syncs with the server
• 27:32 - Handling error states
• 29:26 - Differences between useOptimistic() and Remix fetchers
• 34:57 - How useOptimistic() lets you avoid managing a long-lived client-side cache

Links:

• Ryan’s useOptimistic tweet
• Ryan’s video on React Cache: Part 2