Simple Timer

react-hook-timer.js

const timer = ({ interval = 1000, onTime = () => {} }) => {
  let time = 0;
  let pid = null;

  const stop = () => {
    clearInterval(pid);
  };

  const start = () => {
    pid = setInterval(() => {
      time += 1;
      onTime(time);
    }, interval);
  };

  return {
    stop,
    start,
  };
};

const useTimer = (options) => {
  const [time, setTime] = useState(0);
  const timerRef = useRef(timer({
    ...options,
    onTime: (t) => setTime(t),
  }));
  return {
    time,
    stop: timerRef.current.stop,
    start: timerRef.current.start,
  };
};