基于2个元素的纵向轮播

<template>
  <div class="layer" :style="{ height: height + ‘px‘, width: width + ‘px‘ }">
    <template v-if="list.length == 0">
      <div class="content">暂无数据</div>
    </template>
    <template v-if="list.length == 1">
      <div class="content">{{ list[0] }}</div>
    </template>
    <template v-if="list.length > 1">
      <div class="content">{{ list[0] }}</div>
      <div class="content">{{ list[1] }}</div>
    </template>
  </div>
</template>
<script>
export default {
  name: "swiper",
  data() {
    return {
      timer: null
    };
  },
  props: {
    list: {
      type: Array,
      default: () => {}
    },
    timespace:{
      type: Number,
      default: 3000
    },
    height: {
      default: 30,
      type: Number
    },
    width: {
      default: 300,
      type: Number
    }
  },
  watch: {
    list: {
      immediate: true,
      handler: function(nv, ov) {
        if (nv.length > 1) {
          this.$nextTick(() => {
            this.multiples(1);
          });
        }
      }
    }
  },
  methods: {
    multiples(d) {
      let dom = document.getElementsByClassName("content")[0];
      let layer = document.getElementsByClassName("layer")[0];
      let deg = 0;
      let index = d;
      if (this.timer) {
        clearInterval(this.timer);
        this.timer = null;
      }
      this.timer = setInterval(() => {
        deg = this.height;
        index++;
        dom.style.marginTop = `${-deg}px`;
        setTimeout(() => {
          let newdom = dom.cloneNode(true);
            layer.removeChild(dom);
          newdom.style.marginTop = `0px`;
          let textindex = index % this.list.length;
          newdom.innerHTML = this.list[textindex];
          layer.appendChild(newdom);
            dom = document.getElementsByClassName("content")[0];
            if (index == this.list.length) {
          clearInterval(this.timer);
          this.multiples(0);
          return false
        }
        }, 300);
      }, this.timespace);
    }
  }
};
</script>
<style scoped>
.layer {
  width: 300px;
  height: 30px;
  background: rgba(0, 0, 0, 0.1);
  box-sizing: border-box;
  overflow: hidden;
}
.content {
  height: 100%;
  line-height: 30px;
  transition: all 0.2s linear;
}
</style>

...
<swiper :list="list"></swiper>
....
data(){
  return {
    list: ["第一个元素","第二个元素","第3个元素","第4个元素"]
  }
}