React Countdown

countdown.js

const [countdown, setCountdown] = useState('xx:xx')

function updateCountdown() {
  const totalSeconds = (TARGET_TIMESTAMP - new Date().getTime()) / 1000
  const minutes = Math.floor(totalSeconds / 60)
  const seconds = Math.round(totalSeconds % 60)
  const countdown = `${minutes}:${seconds > 9 ? seconds : '0' + seconds}`
  if (totalSeconds > 1) {
    setCountdown(countdown)
    setTimeout(updateCountdown, 1000)
  } else {
    setCountdown('Reload!')
  }
}

useEffect(() => {
  updateCountdown()
}, [])