React quiz

Test your React knowledge with a free interactive quiz — 50 questions with answers and explanations. No signup needed to play.

What is the purpose of `useMemo`?

1. What is the purpose of `useMemo`?
2. What is a React component?
3. What is React.StrictMode?
4. What does `useRef` return?
5. What does the `children` prop represent?
6. What is lifting state up in React?
7. What are React hooks and when were they introduced?
8. What does `ReactDOM.createRoot()` do in React 18?
9. What causes a React component to re-render?
10. What is a higher-order component (HOC)?
11. What is the difference between controlled and uncontrolled components?
12. What is `useCallback`?

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