danakt · December 3, 2018 13:09
diff --git a/usePrev.ts b/usePrev.ts
 /**
 * React hook to use previous data
 */
 const usePrevious = function<T>(value: T): undefined | T {
  const ref = React.useRef<T | undefined>(undefined);

  React.useEffect(() => {
    ref.current = value;
  });

  return ref.current;
 };
	/**
	* React hook to use previous data
	*/
	const usePrevious = function<T>(value: T): undefined \| T {
	const ref = React.useRef<T \| undefined>(undefined);

	React.useEffect(() => {
	ref.current = value;
	});

	return ref.current;
	};