在React JS中，我正在尝试创建倒计时计时器，但无法将第一秒设置为整秒

import React, { useState, useEffect } from 'react';

function CountdownTimer() {
  const [countdown, setCountdown] = useState(10); // 设置初始倒计时时间为10秒

  useEffect(() => {
    const timer = setInterval(() => {
      setCountdown(prevCountdown => prevCountdown - 1);
    }, 1000);

    return () => {
      clearInterval(timer);
    };
  }, []);

  return (
    <div>
      <h1>倒计时: {countdown}</h1>
    </div>
  );
}

export default CountdownTimer;

import React from 'react';
import CountdownTimer from './CountdownTimer';

function App() {
  return (
    <div>
      <h1>我的应用程序</h1>
      <CountdownTimer />
    </div>
  );
}

export default App;