React useCallback for Performance MCQ useCallback Optimization Practice Questions

Direction: Choose the correct option

How does useCallback improve performance?

A. By memoizing functions so they don't get recreated on each render, preventing child re-renders

B. By memoizing values

C. By optimizing component updates

D. By reducing bundle size

Direction: Choose the correct option

When is useCallback most useful?

A. Never

B. Always

C. When defining event handlers

D. When passing callbacks to optimized child components (like React.memo)

Direction: Choose the correct option

What does useCallback return?

A. A new function each time

B. The original function

C. A ref

D. A memoized version of the callback that only changes if dependencies change

Direction: Choose the correct option

Without useCallback, what happens to a function defined inside a component?

A. A new function is created on every render

B. The function is reused

C. It causes an error

D. It is memoized automatically

Direction: Choose the correct option

Is it necessary to wrap every function in useCallback?

A. No, only when needed for performance optimization

B. Only for event handlers

C. Only in class components

D. Yes, always

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