React useState Quiz

1. What does useState return?

• A. A number and a string

• B. A variable and an object

• C. A stateful value and a function to update it

• D. An array and a map

2. Where can you use useState?

• A. Inside a loop

• B. Inside a class component

• C. Inside a regular function

• D. Inside a functional component

3. What happens when you call the setter function from useState?

• A. It updates the variable instantly

• B. It updates state and re-renders the component

• C. It refreshes the page

• D. It logs the state

4. What is the initial value in useState(0)?

• A. Undefined

• B. The current state

• C. 0

• D. A function

5. What is the correct syntax to update state using useState?

• A. count = count + 1

• B. setCount(count + 1)

• C. useState(count + 1)

• D. update(count)

6. What does map() return?

• A. A new modified array

• B. The original array

• C. A number

• D. Undefined

7. What is required inside map()?

• A. A number

• B. A loop

• C. A callback function

• D. A condition

8. Which of the following correctly uses map()?

• A. arr.map(item => item * 2)

• B. arr.map = (item) => item * 2

• C. map(arr, item => item * 2)

• D. arr.loop(item => item * 2)

9. What is the length of the new array returned by map()?

• A. Same as the original

• B. Always shorter

• C. Always longer

• D. Depends on conditions

10. Can you use map() inside a React component's return statement?

• A. No

• B. Only if it returns a string

• C. Yes, for rendering lists

• D. Only in class components