JSX expressions Fragments Components Props Children Conditional rendering List rendering and keys Event handlers

useState Functional state updates useReducer useRef useId useMemo useCallback Custom hooks

useEffect Effect cleanup Effect dependencies useLayoutEffect useSyncExternalStore Fetching in effects Race-condition cancellation Strict Mode effect behavior

Controlled inputs Uncontrolled inputs Form submission Lifting state up Context useContext forwardRef compatibility patterns Portals

startTransition useTransition useDeferredValue Suspense lazy Error boundaries use action state Optimistic UI

React.memo State colocation Derived state avoidance Reducer architecture Component composition Code splitting Profiler Server/client boundary concepts