usePrevious vs usePreviousValue hooks

index.js

// This hook returns what the value was previously
// even across multiple renders
// (correct for the
// "<button>Value: {value}, previous: {previousValue}</button>"
// use case.
function usePreviousValue(value, defaultValue) {
  const [prev, setPrev] = useState(defaultValue);
  const next = useRef();
  useEffect(() => {
    const old = next.current;
    next.current = value;
    setPrev(old);
  }, [value]);
  // Return previous value (happens before update in useEffect above)
  return prev;
}

// This hook returns what the value was ON THE PREVIOUS RENDER
// (it will be equal to value if the component rerenders from
// other state change).
function usePrevious(value) {
  const ref = useRef();
  useEffect(() => {
    ref.current = value;
  });
  return ref.current;
}