Home React Tutorials Quiz React Quiz (50 Questions) Answer all questions, track your progress live, and see your final result at the end. Progress 0 / 50 answered Q1. What is React mainly used for? Database administration Building user interfaces with components Operating system kernels Email servers Q2. What must a React function component return? Multiple root DOM nodes without a wrapper always Valid React elements (one root or Fragment) Only strings Promises Q3. Which attribute replaces HTML class in JSX? class className classList css Q4. What does useState return? Only the state value A state value and a setter function A DOM node A Promise Q5. Where must hooks be called? Inside loops conditionally At the top level of React functions Inside class constructors only In CSS files Q6. What does useEffect run after by default? Server boot Paint/commit of the render CSS parsing npm install Q7. What should you return from useEffect for cleanup? A string A cleanup function A boolean null always Q8. What is a controlled input? Input managed only by the DOM Input whose value is driven by React state Input without onChange Input type=hidden only Q9. Why are keys important in lists? They style items They help React identify items across renders They replace props They enable CSS Grid Q10. What does React.memo do? Caches network responses Skips re-render when props are shallowly equal Creates Context Hydrates SSR Q11. What is Context used for? SQL queries Passing data through the tree without prop drilling Bundling assets Routing only Q12. What does useRef provide? State that always re-renders A mutable ref object that persists across renders A CSS variable A router Q13. What is JSX? A database language Syntax extension for describing UI in JS A CSS preprocessor A test runner Q14. What does lifting state up mean? Moving state to a common parent Deleting state Storing state in CSS Using localStorage only Q15. Which hook memoizes an expensive calculation? useEffect useMemo useId useDebugValue Q16. Which hook memoizes a callback identity? useCallback useState useLayoutEffect useReducer Q17. What does Strict Mode help with in development? Faster production builds Highlighting potential problems Disabling hooks Removing keys Q18. What is reconciliation? Git merging React updating the DOM to match the virtual tree CSS cascading HTTP caching Q19. Fragments let you… Return multiple children without an extra DOM node Fetch APIs Create class components Skip keys Q20. Default PropTypes are… Required in modern React Optional runtime checks (TypeScript preferred) CSS types Router guards Q21. In React, what best describes 'Introduction'? A key React topic: Introduction Unrelated React concept A Unrelated React concept B Unrelated React concept C Q22. When learning React, why study 'Introduction'? Unrelated React concept A It builds practical skill with Introduction Unrelated React concept B Unrelated React concept C Q23. Which statement about 'Introduction' in React is most accurate? Unrelated React concept A Unrelated React concept B 'Introduction' is a core concept covered in this course Unrelated React concept C Q24. In React, what best describes 'Basics'? Unrelated React concept A Unrelated React concept B Unrelated React concept C A key React topic: Basics Q25. When learning React, why study 'Basics'? It builds practical skill with Basics Unrelated React concept A Unrelated React concept B Unrelated React concept C Q26. Which statement about 'Basics' in React is most accurate? Unrelated React concept A 'Basics' is a core concept covered in this course Unrelated React concept B Unrelated React concept C Q27. In React, what best describes 'Setup'? Unrelated React concept A Unrelated React concept B A key React topic: Setup Unrelated React concept C Q28. When learning React, why study 'Setup'? Unrelated React concept A Unrelated React concept B Unrelated React concept C It builds practical skill with Setup Q29. Which statement about 'Setup' in React is most accurate? 'Setup' is a core concept covered in this course Unrelated React concept A Unrelated React concept B Unrelated React concept C Q30. In React, what best describes 'Create React App'? Unrelated React concept A A key React topic: Create React App Unrelated React concept B Unrelated React concept C Q31. When learning React, why study 'Create React App'? Unrelated React concept A Unrelated React concept B It builds practical skill with Create React App Unrelated React concept C Q32. Which statement about 'Create React App' in React is most accurate? Unrelated React concept A Unrelated React concept B Unrelated React concept C 'Create React App' is a core concept covered in this course Q33. In React, what best describes 'Vite React Setup'? A key React topic: Vite React Setup Unrelated React concept A Unrelated React concept B Unrelated React concept C Q34. When learning React, why study 'Vite React Setup'? Unrelated React concept A It builds practical skill with Vite React Setup Unrelated React concept B Unrelated React concept C Q35. Which statement about 'Vite React Setup' in React is most accurate? Unrelated React concept A Unrelated React concept B 'Vite React Setup' is a core concept covered in this course Unrelated React concept C Q36. In React, what best describes 'Components'? Unrelated React concept A Unrelated React concept B Unrelated React concept C A key React topic: Components Q37. When learning React, why study 'Components'? It builds practical skill with Components Unrelated React concept A Unrelated React concept B Unrelated React concept C Q38. Which statement about 'Components' in React is most accurate? Unrelated React concept A 'Components' is a core concept covered in this course Unrelated React concept B Unrelated React concept C Q39. In React, what best describes 'Functional Components'? Unrelated React concept A Unrelated React concept B A key React topic: Functional Components Unrelated React concept C Q40. When learning React, why study 'Functional Components'? Unrelated React concept A Unrelated React concept B Unrelated React concept C It builds practical skill with Functional Components Q41. Which statement about 'Functional Components' in React is most accurate? 'Functional Components' is a core concept covered in this course Unrelated React concept A Unrelated React concept B Unrelated React concept C Q42. In React, what best describes 'Props'? Unrelated React concept A A key React topic: Props Unrelated React concept B Unrelated React concept C Q43. When learning React, why study 'Props'? Unrelated React concept A Unrelated React concept B It builds practical skill with Props Unrelated React concept C Q44. Which statement about 'Props' in React is most accurate? Unrelated React concept A Unrelated React concept B Unrelated React concept C 'Props' is a core concept covered in this course Q45. In React, what best describes 'State'? A key React topic: State Unrelated React concept A Unrelated React concept B Unrelated React concept C Q46. When learning React, why study 'State'? Unrelated React concept A It builds practical skill with State Unrelated React concept B Unrelated React concept C Q47. Which statement about 'State' in React is most accurate? Unrelated React concept A Unrelated React concept B 'State' is a core concept covered in this course Unrelated React concept C Q48. In React, what best describes 'Rendering'? Unrelated React concept A Unrelated React concept B Unrelated React concept C A key React topic: Rendering Q49. When learning React, why study 'Rendering'? It builds practical skill with Rendering Unrelated React concept A Unrelated React concept B Unrelated React concept C Q50. Which statement about 'Rendering' in React is most accurate? Unrelated React concept A 'Rendering' is a core concept covered in this course Unrelated React concept B Unrelated React concept C Finish Test Your Result