解决Vue3 echarts v-show无法重新渲染的问题

<el-empty class="chart-small" v-if="!dataList || !dataList.length" description="没有数据"/>
<div class="chart-small" ref="dataBarDom" v-show="dataList && dataList.length">

import {ref, onMounted, reactive, nextTick} from "vue";
onMounted(async ()=>{
    getData()
})
// echarts相关
const dataBarDom = ref()//关联图标div的ref
let dataBar = null
// 需要显示的数据（有数据显示，没有数据不显示）
const dataList=ref([])
const getData=async ()=>{
    // 从后台获取需要渲染的数据
    dataList.value=await getDataFromDb()
    if(dataList.value.length){
        showChart.value=true
        nextTick(() => {
            dataBar= echarts.init(dataBarDom.value)
            //...以下省略渲染echart的代码
        })
    }else{
        showChart.value=false
    }
}

  "core-js": "^3.8.3",
    "echarts": "^5.3.2",
    "element-plus": "^2.0.4",
    "vue": "^3.2.13",
    "vue-router": "^4.0.13",
    "vue-ueditor-wrap": "^3.0.8"

      // 基于准备好的dom，初始化echarts实例
      echarts.init(document.getElementById("monthCollect")).dispose();
      var myChart = echarts.init(document.getElementById("monthCollect"));
      myChart.setOption()

// 取得Dom
var main=document.getDocumentByID()
//先获取dom实例，执行销毁
let existInstance = echarts.getInstanceByDom(main);
if (existInstance) {
    if (true) {
        echarts.dispose(chartStudent);
    }
}
// 初始化&配置設定
let mychart = echarts.init(main);
mychar.setOption({....});