Redux

Redux is a predictable centralized store: events describe what happened, pure reducers compute the next state, subscribers read through selectors. Redux Toolkit is the modern default; RTK Query extends Redux for server-state caching.

Subtopics: store, actions, reducers, selectors, middleware, Redux Toolkit, RTK Query.

On interviews: walk the dispatch → reducer → subscribe loop and contrast explicit event history with MobX dependency tracking.

Common pitfalls: storing server cache manually, giant monolithic reducers, and selectors that recompute on every render without memoization.

Checklist:

• Single store with clear slice boundaries.
• Serializable actions; pure reducers.
• Selectors for reads and derived data.
• Middleware/RTK Query for async and remote data.