React 19 Interview Questions and Answers
React 19 is now the baseline, and interviewers are starting to ask about its new features. Here's what to know.
What are Actions in React 19?
Async functions React manages for you. Pass one to a <form>'s action prop and React tracks pending state, errors and optimistic updates automatically — no onSubmit or manual loading flag.
What does useActionState do?
It connects an async action to state, returning [state, wrappedAction, isPending] — replacing the manual useState + try/catch + isLoading pattern for forms.
What is useOptimistic?
It shows a provisional value while an action is pending and automatically reverts to real state on completion/failure — making optimistic UI a hook instead of manual snapshot/rollback.
What is the use() API?
use() reads a Promise or Context during render. Unlike other hooks it can be called conditionally; with a Promise it suspends the component (pair with Suspense).
Do you still need forwardRef in React 19?
No — function components can receive ref as a normal prop now. forwardRef still works for existing code but isn't needed for new components.
Stay current with React 19
A dedicated React 19 chapter plus 75+ Q&A — Actions, useOptimistic, useActionState and use() in the React Interview Kit.
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- What's the theme of React 19?
- Actions — async work React manages end to end. The new hooks remove the boilerplate around form submission (pending, error, optimistic state).
- Should I learn React 19 for interviews?
- Yes — it's stable and increasingly expected. Know Actions, the new hooks and the use() API.