React Hooks

Question 1

What is useState in React?

Accepted Answer

A hook that adds state to functional components, returning the current value and a function to update it

Answer

A CSS property

Answer

A routing function

Answer

A testing utility

Question 2

What is useEffect used for?

Accepted Answer

Performing side effects like data fetching, subscriptions, or DOM manipulation after render

Answer

Adding visual effects

Answer

Creating animations only

Answer

Error handling

Question 3

What is the dependency array in useEffect?

Accepted Answer

An array of values that determines when the effect should re-run — changes trigger re-execution

Answer

A list of npm packages

Answer

A required parameter

Answer

An error array

Question 4

What is useContext?

Accepted Answer

A hook that accesses context values without wrapping components in Consumer, enabling shared state across the component tree

Answer

A debugging tool

Answer

A state manager

Answer

A routing hook

Question 5

What is useRef used for?

Accepted Answer

Creating a mutable reference that persists across renders without causing re-renders when changed

Answer

Creating references to other files

Answer

A type of state

Answer

A routing parameter

Question 6

What is useMemo?

Accepted Answer

A hook that memoizes expensive calculations, only recomputing when dependencies change

Answer

A note-taking hook

Answer

A memory management tool

Answer

A memo component