React Hooks Introducing React Hooks 5

Question 1

Which Hook is an alternative to useState for complex state logic?

Accepted Answer

useReducer

Answer

useReducer is preferable when state logic is complex or the next state depends on the previous one.

Question 2

What does useRef primarily return?

Accepted Answer

A mutable object whose .current persists across renders

Answer

useRef returns a mutable ref object with a .current property that persists between renders.

Question 3

What is the main purpose of the useMemo Hook?

Accepted Answer

To memoize an expensive computed value

Answer

useMemo caches the result of an expensive calculation and recomputes only when dependencies change.

Question 4

How does useCallback differ from useMemo?

Accepted Answer

useCallback memoizes a function, useMemo memoizes a value

Answer

useCallback returns a memoized callback while useMemo returns a memoized value.

Question 5

Why are dependency arrays important in Hooks like useEffect and useMemo?

Accepted Answer

They tell React when to re-run or recompute

Answer

The dependency array tells React which values, when changed, should trigger the Hook to re-run.

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