React Hooks and Lifecycle

Assess your ability to use useState,useEffect,and custom hooks effectively.

1. What does the useState hook return?

An array with [currentValue, setterFunction] A single value An object with {value, setValue} A function that updates the state

2. Which of the following are lifecycle methods in class components?

componentDidMount componentDidUpdate componentWillUnmount useState

3. useState can only store primitive values (strings, numbers, booleans).

True False

4. What hook is used to directly access a DOM element or keep a mutable value that doesn't trigger re-renders?

5. Which React Hook is used to manage complex state logic with a reducer function?

useState useReducer useContext useRef

6. Which of the following are valid dependencies for the useEffect dependency array?

A state variable declared with useState A prop passed to the component A function defined inside the component A DOM element

7. useEffect with no dependency array runs after every render, including the initial mount.

True False

8. What is the term for a function that cleans up side effects, returned by the function passed to useEffect?

9. Which hook is used to memoize the result of an expensive calculation to avoid re-computing on every render?

useCallback useMemo useRef useReducer

10. Which lifecycle events can be mimicked using useEffect?

componentDidMount componentDidUpdate componentWillUnmount componentWillMount

11. Custom hooks can call other hooks.

True False

12. What rule states that hooks must be called only at the top level of function components or custom hooks?

13. What happens if you update state inside useEffect without including the state in the dependency array?

The effect will not re-run when the state changes The component will unmount immediately The state will not update React will throw an error

14. Which of the following are considered 'built-in' React Hooks?

useState useEffect useLocalStorage useContext

15. useLayoutEffect runs synchronously after all DOM mutations, before the browser paints.

True False

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