React Unpacked A Roadmap to React 19
summary
Demo shows React 19’s new action primitives eliminating race conditions in a cart example: switching from manual async handlers to form action and useActionState removes stale updates and revalidation races while preserving a pending UI. startTransition/useTransition support async actions, useOptimistic offers reversible optimistic updates that revert when all actions settle, and server actions + server components let forms call server code directly. The demos run live, pending/error indicators work, and batched updates reduce duplicate refreshes.
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chapters (11)
- 0:00Introduction to React 19
- 3:11Race conditions in async code
- 4:15Solving race conditions with startTransition
- 7:09Pending state with useTransition
- 8:13Actions on forms
- 11:05useFormStatus for pending UI
- 13:14useActionState for state management
- 15:00Return values from actions
- 19:15Optimistic updates with useOptimistic
- 23:29Server components and actions
- 28:10Future of actions in React
