This function, named `useResentCodeTimer`, is a custom React hook that manages a countdown timer for a resend code functionality

useResentCodeTimer.ts

import { useState, useEffect } from 'react';

interface ResentCodeTimerProps {
  initialValue?: number;
}

export const useResentCodeTimer = ({ initialValue = 60 }: ResentCodeTimerProps) => {
  const [resentCodeIn, setResentCodeIn] = useState(initialValue);
  let startTime: Date | undefined;

  useEffect(() => {
    if (resentCodeIn > 0) {
      startTime = new Date();
    } else {
      startTime = undefined;
    }

    const intervalId = setInterval(() => {
      if (startTime) {
        const elapsed = Math.floor((new Date() - startTime) / 1000);
        setResentCodeIn(Math.max(initialValue - elapsed, 0));
        if (elapsed >= initialValue) {
          clearInterval(intervalId);
        }
      }
    }, 100);

    return () => {
      clearInterval(intervalId);
    };
  }, [resentCodeIn, initialValue]);

  return resentCodeIn;
};