cnpm i dayjs --save

// main.ts

import dayjs from 'dayjs'

const app = createApp(App);
app.use(store).use(router).use(ElementPlus).mount('#app')
app.config.globalProperties.day=dayjs//全局掛載

//使用的頁(yè)面
//引用getCurrentInstance 
import { reactive,toRefs,getCurrentInstance} from 'vue'


 setup() {
        const { proxy } = getCurrentInstance() as any; 
          const day =proxy.day
          const data= reactive({
          })
          const refData = toRefs(data);
          return {
              ...refData,
              day
          }

      }

<template>
  <div>
    {{day('20170113').format("YYYY-MM-DD HH:mm:ss")}}
  </div>
</template>

import dayjs from 'dayjs'
//然后return出去
 return {
          day
          }

<template>
  <div>
    {{day('20170113').format("YYYY-MM-DD HH:mm:ss")}}
  </div>
</template>

npm install dayjs -S

import dayjs from "dayjs";
app.config.globalProperties.day = dayjs;

<el-table-column prop="validityDateEnd" :label="$t('user.validityDateEnd')" sortable="custom" header-align="center" align="center">
    <template v-slot="scope">
          {{ dayjs(scope.row.validityDateEnd).format("YYYY-MM-DD") }}
    </template>
</el-table-column>

validityDateStart: dayjs(dataForm.validityDate[0]).format(),
validityDateEnd: dayjs(dataForm.validityDate[1]).format()