Vue——制作跑马灯效果

先上效果图，解释都在代码注释里边
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document
    </title>
</head>


<body>
    <div id="app">
        <input type="button" value="帅起来" @click='shuai'>
        <input type="button" value="歇会儿" @click='stop'>
        <div>{{ msg }}</div>
    </div>

    <script src="https://unpkg.com/vue@2.6.10/dist/vue.js"></script>
    <script>
        var vm = new Vue({
            el: '#app',
            data: {
                msg: '屏幕前的你，很帅~~~',
                intervalId: null //在data上定义 定时器ID
            },
            methods: {
                shuai() { // 开启跑动
                    if (this.intervalId != null) return//设置一个锁，防止开启多个定时器
                    this.intervalId = setInterval(() => {
                        let start = this.msg.substring(0, 1)//获取到头的第一个字符
                        let end = this.msg.substring(1)//获取到 后面的所有字符
                        this.msg = end + start //重新拼接得到新的字符串并赋值给this.msg
                    }, 400)
                },
                stop() { //停止定时器
                    clearInterval(this.intervalId)//清理定时期
                    this.intervalId = null//再把this.intervalId设置为null(暂停后可以再次开启跑动)
                }
            }
        })
    </script>
</body>

</html>