React Hooks Custom Hooks 2

Question 1

Which built-in hook pair is most commonly combined in a useFetch custom hook?

Accepted Answer

useState and useEffect

Answer

A useFetch hook typically uses useState to store data/loading/error and useEffect to trigger the fetch.

Question 2

How should a custom hook expose a way to update shared logic state to its consuming component?

Accepted Answer

By returning a setter or action function from the hook

Answer

Returning a setter or action function from the custom hook lets the consumer trigger state changes cleanly.

Question 3

What is a useLocalStorage custom hook typically used for?

Accepted Answer

Persisting state to localStorage and syncing it with component state

Answer

useLocalStorage wraps useState with read/write logic for localStorage, keeping them in sync.

Question 4

Can a custom hook call another custom hook?

Accepted Answer

Yes, hooks can call other hooks freely

Answer

Custom hooks are just functions, so they can freely call other custom or built-in hooks.

Question 5

Why is it important to clean up side effects in custom hooks?

Accepted Answer

To prevent memory leaks and stale subscriptions when components unmount

Answer

If a custom hook sets up a subscription or interval, failing to clean it up causes memory leaks after the component unmounts.

React Practice Test