如果已设置,如何使用 btn 清除间隔

How to clear interval with a btn if it's already set

所以我目前对 JavaScript 和它的概念还很陌生,我正在尝试制作一个游戏,其中有 4 个 btns 启动计时器,然后重置它并在它们中的任何一个出现时再次启动它第二次按下,但每当我按下任何按钮两次时,它就会将计时器加速 2 倍,而不是重置并重新启动它

这是我的代码, 很抱歉,如果它很乱 and/or 难以理解

let time = 5
const countDown = document.querySelector('#countdown')
let challenge = document.getElementById('text')
const btns = document.querySelectorAll('.btn')
let text = ''

function randomText(){
  return Math.floor(Math.random() * arr.length)
}

btns.forEach(function(btn){
  btn.addEventListener('click', function(e){
    time = 5
    const timer = setInterval(countdown, 1000)
    text = arr[randomText()]
    challenge.textContent = text
  })
})



function countdown(){
  if( time === 0 ){
    time = 5
}
  time--
  countDown.innerHTML = `00:0${time}`
} 
let timer;
btns.forEach(function(btn){
  btn.addEventListener('click', function(e){
    time = 5
    clearInterval(timer);
    timer = setInterval(countdown, 1000)
    text = arr[randomText()]
    challenge.textContent = text
  })
})