【JavaScript】- whack-a-mole game (timer nested delayer)

The method of timer nested delayer is used here

js：

window.addEventListener('load', () => {
    // 获取元素
    let start = document.querySelector('.start')    // 开始按钮
    let mole = document.querySelectorAll('.mole')    // 打鼹鼠
    let score = document.querySelector('.score')    // 数字文本
    let timerId     // 定时句柄
    let index       // 随机数索引
    let num = 0     // 击打次数


    // 开始添加点击事件
    start.addEventListener('click', () => {

        // 重新点击开始，击打次数清零
        num = 0
        score.innerHTML = num

        start.style.display = 'none'    // 隐藏开始按钮，以防多次点击出现定时器bug
   
        timerId = setInterval(() => {       // 添加打地鼠定时器
            // 生成随机数
            index = parseInt(Math.random() * mole.length)
            mole[index].style.top = '0%'        // 设置地鼠样式从下往上出来
            time = setTimeout(() => {           // 添加定时器嵌套延时器，延时器只执行一遍
                mole[index].style.top = '70%'      // 设置地鼠样式钻回地底
            }, 500)
        }, 1000)
        
        // 添加倒计时10秒后停止打地鼠定时器
        setInterval(() => {
            start.style.display = 'block'
            clearInterval(timerId)
        }, 10000)
    })

    // 点击敲打鼹鼠
    mole.forEach((value, index) => {
        value.addEventListener('click', () => {
            mole[index].style.top = '70%'
            num++
            score.innerHTML = num
        })
    });

html：

    <h1>Whack-a-mole! <span class="score">0</span></h1>
    <p><button class="start">Start</button></p>

    <div class="game">
        <div class="hole hole1">
            <div class="mole"></div>
        </div>
        <div class="hole hole2">
            <div class="mole"></div>
        </div>
        <div class="hole hole3">
            <div class="mole"></div>
        </div>
        <div class="hole hole4">
            <div class="mole"></div>
        </div>
        <div class="hole hole5">
            <div class="mole"></div>
        </div>
        <div class="hole hole6">
            <div class="mole"></div>
        </div>
    </div>

    <h2 class="game-status"></h2>

    <script src="./index.js"></script>

css：

html {
    box-sizing: border-box;
    font-size: 10px;
    background: #ffc600;
}

*,
*:before,
*:after {
    box-sizing: inherit;
}

body {
    padding: 0;
    margin: 0;
    font-family: 'Amatic SC', cursive;
}

h1,
h2 {
    text-align: center;
    font-size: 10rem;
    line-height: 1;
    margin-bottom: 0;
}

h2 {
    font-size: 8rem;
}

.score {
    background: rgba(255, 255, 255, 0.2);
    padding: 0 3rem;
    line-height: 1;
    border-radius: 1rem;
}

p {
    height: 5rem;
    text-align: center;
}

button {
    margin: 0 auto;
    width: 10rem;
    font-size: 3rem;
    font-family: 'Amatic SC', cursive;
    -webkit-appearance: none;
    appearance: none;
    font-weight: bold;
    background: rgba(255, 255, 255, 0.2);
    border: 1px solid black;
    border-radius: 1rem;
}

.game {
    width: 600px;
    height: 400px;
    display: flex;
    flex-wrap: wrap;
    margin: 0 auto;
}

.hole {
    flex: 1 0 33.33%;
    overflow: hidden;
    position: relative;
}

.hole:after {
    display: block;
    background: url(dirt.svg) bottom center no-repeat;
    background-size: contain;
    content: '';
    width: 100%;
    height: 70px;
    position: absolute;
    z-index: 2;
    bottom: -30px;
}

.mole {
    background: url('mole.svg') bottom center no-repeat;
    background-size: 60%;
    position: absolute;
    top: 70%;
    width: 100%;
    height: 100%;
    transition: all 0.4s;
}

.hole.up .mole {
    top: 0;
}