javascript - Do we still need functional setState way in react hooks?

Question

  const [count, setCount] = useState(0);

  const handleClick = () =>
    setCount(prevCount => {
      return prevCount + 1;
    });

  const [count, setCount] = useState(0);

  const handleClick = () => setCount(count + 1);

Coming from class-based component background, it becoming a habit where we use functional setState. I'm wondering if do we still need to rely on prevState in functional hooks? Or the current state is always "trustable" and most "updated"?

Answer 1

Yes, the behavior is similar.

React is batching the updates calls. When Writing:

const handleClick = () => setCount(count + 1)
handleClick()
handleClick()
handleClick()

the count in state will be 1

When Writing:

const handleClick = () =>
  setCount(prevCount => {
    return prevCount + 1;
});
handleClick()
handleClick()
handleClick()

the count in state will be 3