React Quiz

Basics of React

1. What is React?
2. Who developed React?
3. In which year was React released?
4. What is the latest stable version of React? (as of your knowledge)
5. What is JSX?
6. Is JSX mandatory in React?
7. What is the virtual DOM?
8. What are components in React?
9. What are the types of components in React?
10. What is the difference between functional and class components?
11. What are props in React?
12. What is state in React?
13. Can props be changed?
14. How do you create a functional component?
15. How do you create a class component?
16. What is the render() method?
17. What is the purpose of ReactDOM.render()?
18. Can you return multiple elements from a component?
19. What is a fragment in React?
20. What is the use of key in lists?

React JSX

21. What does JSX stand for?
22. Can browsers understand JSX?
23. How do you write expressions in JSX?
24. How do you comment inside JSX?
25. Can we use if condition inside JSX?
26. What is the correct way to apply inline CSS in JSX?
27. Can JSX elements be self-closing?
28. What is the difference between class and className in JSX?
29. How do you bind events in JSX?
30. What is the role of curly braces {} in JSX?

React Props and State

31. What is the difference between props and state?
32. How do you pass props to a component?
33. Can you use props in a class component?
34. How do you update state in a class component?
35. How do you update state in a functional component?
36. What is the use of useState()?
37. Is state mutable?
38. Can a component have multiple states?
39. Can props be functions?
40. Can we use props in useEffect()?

React Lifecycle

41. What are React lifecycle methods?
42. Name lifecycle methods in class components.
43. What is componentDidMount() used for?
44. What does componentWillUnmount() do?
45. What is the equivalent of componentDidMount() in hooks?
46. What is useEffect()?
47. How does useEffect() work?
48. Can we use multiple useEffect() hooks?
49. How do you stop useEffect from running every time?
50. What does the cleanup function in useEffect do?

React Hooks

51. What are hooks?
52. When were hooks introduced in React?
53. Can you use hooks inside class components?
54. What is useState()?
55. What is useEffect()?
56. What is useContext()?
57. What is useRef()?
58. What is useMemo()?
59. What is useCallback()?
60. What is a custom hook?
61. Can we call hooks conditionally?
62. What are the rules of hooks?

React Routing

63. What is React Router?
64. How do you install React Router?
65. What is <BrowserRouter>?
66. What is <Route>?
67. What is <Link>?
68. What is the difference between <Link> and <a> tag?
69. How to redirect to another page in React?
70. What is the use of useNavigate()?
71. What is dynamic routing in React?
72. What is nested routing?

React Forms

73. What are controlled components?
74. What are uncontrolled components?
75. How do you handle forms in React?
76. What is the use of onChange()?
77. How do you prevent form submission from refreshing the page?
78. What is event.target.value?

Advanced React

79. What is Context API?
80. Why do we need Context API?
81. How do you create a context?
82. What is useContext() used for?
83. What is prop drilling?
84. How does React handle performance optimization?
85. What is memoization in React?
86. What is React.memo()?
87. What is reconciliation?
88. What is lazy loading in React?
89. What is suspense in React?
90. What are error boundaries?

React with Other Tools

91. What is Redux?
92. What is the use of Redux in React?
93. What are actions and reducers?
94. What is the Provider in Redux?
95. What is the difference between Redux and Context API?
96. How do you connect Redux to a React app?
97. What is a middleware in Redux?

Miscellaneous & Best Practices

98. What are keys in React and why are they important?
99. How to debug a React app?
100. What is code splitting?
101. How do you optimize React performance?
102. What is the difference between React and Angular?
103. What is the importance of index.js?
104. How do you deploy a React app?
105. What is Create React App (CRA)?
106. Can React be used for mobile apps?
107. What is React Native?
108. What are higher-order components (HOC)?
109. What is server-side rendering (SSR)?
110. What are portals in React?