React

JSX and rendering model

Hooks: useState/useEffect basics

Component composition patterns

Forms basics

Error boundaries overview

Lifting state up

Context patterns (when/why)

State libraries overview

Server state vs UI state

Memoization basics (useMemo/useCallback)

Fetching patterns and caching

Pagination/infinite queries overview

Optimistic updates overview

Error and loading UX patterns

API contracts with TS overview

Client-side routing basics

Protected routes patterns

Code splitting

SSR/SSG overview

SEO considerations overview

Component tests with Testing Library

Mocking network requests

E2E overview (Playwright)

CI test runs

Performance basics and profiling