40 of 40 questions
// Interview Deck · REACT
React
Hooks, component lifecycle, rendering behavior, and the patterns that separate 'using React' from 'understanding React.'
01
Beginner
What is React and why use it? (Virtual DOM concept)
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02
Beginner
What is JSX?
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03
Beginner
Difference between functional and class components?
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04
Beginner
What are props in React?
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05
Beginner
What is state in React?
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06
Beginner
Difference between props and state?
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07
Beginner
Explain the useState hook.
Card #7View Answer
08
Intermediate
Explain the useEffect hook and how the dependency array works.
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09
Intermediate
What is the component lifecycle and how do hooks relate to it?
Card #9View Answer
10
Beginner
How does conditional rendering work in React?
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11
Beginner
How do lists and keys work in React?
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12
Beginner
How does event handling work in React?
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13
Intermediate
Difference between controlled and uncontrolled components?
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14
Intermediate
What does 'lifting state up' mean in React?
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15
Intermediate
Explain the useRef hook.
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16
Intermediate
Explain useContext and the Context API.
Card #16View Answer
17
Intermediate
Explain the useMemo hook.
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18
Intermediate
Explain the useCallback hook.
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19
Intermediate
What are custom hooks and why use them?
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20
Intermediate
Explain the useReducer hook.
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21
Advanced
What is React Fiber and reconciliation?
Card #21View Answer
22
Beginner
Difference between Virtual DOM and Real DOM?
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23
Intermediate
Why is using the array index as a key a bad practice?
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24
Intermediate
What is prop drilling?
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25
Intermediate
What is React.memo and when should you use it?
Card #25View Answer
26
Beginner
What are Fragments in React?
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27
Intermediate
What are Portals in React?
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28
Intermediate
What are Error Boundaries in React?
Card #28View Answer
29
Advanced
What is a Higher-Order Component (HOC)?
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30
Advanced
What is the render props pattern?
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31
Advanced
Difference between useLayoutEffect and useEffect?
Card #31View Answer
32
Beginner
What is Strict Mode in React?
Card #32View Answer
33
Intermediate
Explain React Router basics — routing, navigation, and dynamic routes.
Card #33View Answer
34
Intermediate
How do forms and basic validation work in React?
Card #34View Answer
35
Advanced
What are common ways to optimize performance in a React app?
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36
Intermediate
What is lazy loading and how do React.lazy and Suspense work?
Card #36View Answer
37
Advanced
Difference between Server Components and Client Components? (React 18+ / Next.js)
Card #37View Answer
38
Intermediate
What are Pure Components?
Card #38View Answer
39
Intermediate
What are Synthetic Events in React?
Card #39View Answer
40
Intermediate
Why shouldn't keys be random or change on every render?
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