useInterval.js

import { useEffect } from 'react';
import useCommittedRef from './useCommittedRef';
/**
 * Creates a `setInterval` that is properly cleaned up when a component unmounted
 *
 * ```tsx
 *  function Timer() {
 *    const [timer, setTimer] = useState(0)
 *    useInterval(() => setTimer(i => i + 1), 1000)
 *
 *    return <span>{timer} seconds past</span>
 *  }
 * ```
 *
 * @param fn an function run on each interval
 * @param ms The milliseconds duration of the interval
 */

function useInterval(fn, ms, paused, runImmediately) {
  if (paused === void 0) {
    paused = false;
  }

  if (runImmediately === void 0) {
    runImmediately = false;
  }

  var handle;
  var fnRef = useCommittedRef(fn); // this ref is necessary b/c useEffect will sometimes miss a paused toggle
  // orphaning a setTimeout chain in the aether, so relying on it's refresh logic is not reliable.

  var pausedRef = useCommittedRef(paused);

  var tick = function tick() {
    if (pausedRef.current) return;
    fnRef.current();
    schedule(); // eslint-disable-line no-use-before-define
  };

  var schedule = function schedule() {
    clearTimeout(handle);
    handle = setTimeout(tick, ms);
  };

  useEffect(function () {
    if (runImmediately) {
      tick();
    } else {
      schedule();
    }

    return function () {
      return clearTimeout(handle);
    };
  }, [paused, runImmediately]);
}

export default useInterval;