elementplus中Carousel 走马灯不自动轮播

最初代码：

<el-carousel height="320px">
   <el-carousel-item v-for="item in imgs" :key="item">
        <img class="carouselImg" :src="item">
    </el-carousel-item>
</el-carousel>

const imgs = ref([])
onMounted(async() => {
    const res = await scanBanner()
    res.code == 200 && (imgs.value = res.data.images.split(',')) //返回数据为字符串，切割成数组
})

结果图片可以正常显示，鼠标点击也能正常切换，但无法自动轮播。怀疑是imgs初始值为空的原因。修改如下：

<el-carousel height="320px" v-if="imgs.length">  //加了if判断，轮播可自动播放
   <el-carousel-item v-for="item in imgs" :key="item">
        <img class="carouselImg" :src="item">
    </el-carousel-item>
</el-carousel>