Senior React questions should connect framework mechanics to product behavior and maintenance. Practice each answer with a concrete scenario, a failure mode, and a verification approach.
Rendering and identity
- What causes a component to render, and when is that harmless?
- How does identity affect state preservation?
- When does memoization improve performance, and when does it add noise?
- How would you diagnose an unexpectedly expensive interaction?
- What assumptions change with concurrent rendering?
State and effects
- Where should state live for a multi-step workflow?
- Which values should be derived rather than stored?
- How do you distinguish an event from synchronization?
- How do stale closures appear in production?
- How would you model loading, empty, success, stale, and error states?
Data and application boundaries
- What belongs in a server-state cache?
- How should mutation and invalidation work?
- Where do schema validation and authorization belong?
- How would you design optimistic updates and rollback?
- What should a feature boundary expose?
Quality and scale
- How do accessibility requirements shape component APIs?
- What should component tests prove?
- How do you prevent a design system from becoming an exception system?
- When would you introduce code splitting?
- How would you migrate a large legacy React surface incrementally?
What a strong answer contains
- The user-visible behavior
- The React mechanism involved
- A concrete failure mode
- A maintainable implementation direction
- A way to observe or test the result
Primary sources
Editorial review
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