React Fundamentals

What React is (component-based UI library), Vite project setup, JSX syntax (expressions, attributes, fragments), function components, component composition, importing and exporting components, React DevTools

Props (passing data down, destructuring, children), useState hook (primitive and object state), state updates and immutability, lifting state up, prop drilling problem, TypeScript with React (typed props/state)

Event handlers (onClick, onChange, onSubmit), synthetic events, controlled components (input/select/textarea), form submission and prevention, form validation patterns, multiple form fields with single handler

Rendering lists with map(), key prop and why it matters, conditional rendering (&&, ternary, early return), useEffect for side effects, dependency arrays, cleanup functions, fetching data on mount

React Router v7 (BrowserRouter, Routes, Route), Link and NavLink, route parameters (useParams), programmatic navigation (useNavigate), nested routes and outlets, protected routes pattern, 404 pages

Fetching data with fetch/axios, loading/error/data pattern, custom hooks (useApi, useFetch), useReducer for complex state, context API for shared state (avoiding prop drilling), when to use context vs props