React
Hooks, reconciliation, performance, Suspense, RSC and interview questions
Go deep on React: JSX and composition, the core and custom hooks, controlled forms, lists and keys, the virtual DOM, Fiber and reconciliation, performance with memoization and React.memo, error boundaries, Suspense and concurrent UI, global state choices (Context, Redux Toolkit, Zustand), testing with React Testing Library, and Server Components. Each topic pairs a senior-level explanation with realistic JSX and the pitfalls and follow-ups interviewers probe.
Components & JSX 2 topics
Hooks 5 topics
useState: batching & immutability
Functional updates, batching, lazy init, and derived-state pitfalls.
useEffect, races & when not to use it
Dependencies, cleanup, race conditions, and effect-vs-render distinctions.
useContext & avoiding re-render storms
Context for shared state, its performance trap, and how to split it.
useReducer for complex state
Reducer patterns, when to prefer it over useState, and testability.
Custom hooks & the rules of hooks
Extracting reusable logic, hook rules, and subscribing to external stores.
Core concepts 2 topics
Performance 2 topics
State management 1 topics
Advanced 4 topics
Error boundaries
Catching render errors and showing fallback UI without crashing the app.
Suspense, lazy & concurrent UI
Declarative loading states, code splitting, and useTransition.
Testing with React Testing Library
Testing behaviour via the DOM, user-event, and async utilities.
React Server Components
Server vs client components, streaming, and the mental model.
Interview questions 3 topics
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