TombayRetirementTimer/src/hooks/useCountdown.js

import { useEffect, useState } from 'react';

const useCountdown = (targetDate) => {
 const countDownDate = new Date(targetDate).getTime();

 const [countDown, setCountDown] = useState(
   countDownDate - new Date().getTime()
 );

 useEffect(() => {
   const interval = setInterval(() => {
     setCountDown(countDownDate - new Date().getTime());
   }, 1000);

   return () => clearInterval(interval);
 }, [countDownDate]);

 return getReturnValues(countDown);
};

const getReturnValues = (countDown) => {
 // calculate time left
 const days = Math.floor(countDown / (1000 * 60 * 60 * 24));
 const hours = Math.floor(
   (countDown % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60)
 );
 const minutes = Math.floor((countDown % (1000 * 60 * 60)) / (1000 * 60));
 const seconds = Math.floor((countDown % (1000 * 60)) / 1000);

 return [days, hours, minutes, seconds];
};

export { useCountdown };