FCC 25 + 5时钟计时器未到达00:00

Question

我一直在进行免费代码训练营的25 + 5时钟挑战，其中6项测试一直失败，结果仍然相同，说“计时器未达到00:00”，但确实成功了当我看着它倒数时为零。这个版本是用香草JS完成的，我现在看到在React中可能会更好。有什么想法吗？

这是我的CodePen：https://codepen.io/mplatt212/pen/OJNxJJr

以下是最相关的JS：

    const reset = document.querySelector('#reset');
const startStop = document.querySelector('#start_stop');
const breakLabel = document.querySelector('#break-label');
var breakLength = document.querySelector('#break-length');
const breakDown = document.querySelector('#break-decrement');
const breakUp = document.querySelector('#break-increment');
const sessionLabel = document.querySelector('#session-label');
const sessionLength = document.querySelector('#session-length');
const sessionDown = document.querySelector('#session-decrement');
const sessionUp = document.querySelector('#session-increment');
var timerLabel = document.querySelector('#timer-label');
var timeLeft = document.querySelector('#time-left');
var beep = document.querySelector('#beep');
var toggle = false;

breakLength.innerHTML = '5';
sessionLength.innerHTML = '25';
timeLeft.innerHTML = '25:00';
var timer = (parseInt(timeLeft.innerHTML.split(':')[0]) * 60 * 1000) + (parseInt(timeLeft.innerHTML.split(':')[1]) * 1000);

breakTimer = () => {
  let breakTime = parseInt(breakLength.innerHTML) * 60 * 1000;
    let breakInterval = setInterval(() => {
      if(breakTime == 0){
        timer = parseInt(sessionLength.innerHTML) * 60 * 1000;
        timerStart();
        timerLabel.innerHTML = 'Session';
        clearInterval(breakInterval);
        //beep.play();
      }
      if(toggle){
        timeLeft.innerHTML = msToTime(breakTime);        
        breakTime -= 1000;
      } else {
        clearInterval(breakInterval);
        return;
      }
    }, 1000)
}

timerStart = () => {
  let sessionInterval = setInterval(() => {
    if(timer == 0){
      breakTimer();
      timerLabel.innerHTML = 'Break';
      clearInterval(sessionInterval);
      beep.play();
      return;
    }
    if(toggle){
      timer -= 1000;
      timeLeft.innerHTML = msToTime(timer);
    } else {
      clearInterval(sessionInterval);
      return;
    }
  }, 1000)
};

如果您需要进一步说明，请告诉我。谢谢您的时间。