Quiz for useRef

Q1: What does the useRef hook primarily allow you to do?

A. Access and manipulate DOM elements directly B. Manage component state C. Perform side effects D. Handle routing

Q2: How do you create a ref using useRef?

A. const myRef = useRef(initialValue) B. const myRef = createRef() C. const myRef = new Ref() D. const myRef = useState()

Q3: What is the initial value of the ref object returned by useRef?

A. null B. undefined C. The value passed to useRef() D. Zero

Q4: Does updating the .current property cause a component re-render?

A. Yes B. No C. Only if setState is called D. Only in class components

Q5: Which useRef use case involves storing a previous value?

A. Managing DOM nodes B. Storing mutable values that persist between renders C. Fetching data D. Handling routes

Q6: Can useRef be used to store timers or interval IDs?

A. No B. Yes C. Only with useState D. Only with useEffect

Q7: How do you access the DOM element using a ref?

A. myRef.value B. myRef.current C. myRef.get() D. myRef.dom

Q8: What happens if you use useRef to attach a ref to a React component?

A. You get the component instance B. You get the DOM node C. You get null D. It throws an error

Q9: What is a common alternative to useRef for managing mutable variables?

A. useState B. useEffect C. useCallback D. There is no good alternative

Q10: Can you use useRef to avoid re-initializing a value on every render?

A. Yes B. No C. Only in class components D. Only with useState

Q11: What type of object does useRef return?

A. Mutable object with .current property B. Immutable object C. Function D. Promise

Q12: How does useRef differ from useState?

A. useRef causes rerender, useState does not B. useState causes rerender, useRef does not C. Both cause rerenders D. Neither causes rerenders

Q13: What is a typical use case of useRef in forms?

A. Handling controlled inputs B. Managing focus and cursor position C. Styling inputs D. Fetching form data

Q14: Is it possible to use useRef to store previous props or state?

A. Yes B. No C. Only for props D. Only for state

Q15: Which React feature can replace some use cases of useRef?

A. useCallback B. useMemo C. useState D. useEffect

Q16: What happens if you assign a new value to myRef.current?

A. Triggers component rerender B. Does not trigger rerender C. Resets state D. Throws error

Q17: Can you use useRef to store an interval ID for cleanup?

A. Yes B. No C. Only with useState D. Only in class components

Q18: Where should you NOT call useRef?

A. Inside loops or conditions B. At top level of component C. Inside event handlers D. Inside effects

Q19: Does useRef replace the need for component instance variables in class components?

A. Yes B. No C. Only sometimes D. Only with state

Q20: Can useRef be used to store DOM nodes?

A. Yes B. No C. Only with useEffect D. Only in class components