Useref in react theory question

1. What is useRef in React?

• Answer: useRef is a React hook that returns a mutable object (.current) whose value persists across re-renders.
• Example: const myRef = useRef(null);

1. What’s the difference between useRef and useState?

• useState triggers re-renders when updated.
• useRef does not trigger re-renders when .current changes.

1. When should you use useRef instead of useState?

• When you want to store values that:

  • Don’t affect rendering.
  • Should persist between renders (like timers, previous values, DOM references).

1. How does useRef help in accessing the DOM?

• useRef stores a reference to a DOM element that you can access directly.
• Example: myRef.current.focus() to focus an input.

1. What happens if you update a useRef value? Does the component re-render?

• No. Updating .current does not cause re-render.

1. Difference between useRef and createRef?

• createRef is re-created on each render (used in class components).
• useRef persists the same object between renders.

1. Can useRef be used to store previous state values?

• Yes, by manually updating .current inside useEffect.

1. Can you pass useRef between components?

• Yes, but usually with forwardRef to expose refs from child to parent.

1. What is the initial value of a useRef object?

• Whatever you pass inside useRef(initialValue) → stored in .current.

1. Why is useRef called a “box” object in React docs?

* Because `.current` acts like a box where you put a value and retrieve it without triggering re-renders.

---