1、按需导入时如何进行组件库语言切换：

<template>
  <el-config-provider :locale="zhCn">
    <el-table :data="tableData" style="width: 100%">
...
    </el-table>
  </el-config-provider>
</template>

<script lang="ts" setup>
import zhCn from "element-plus/es/locale/lang/zh-cn";
</script>

<style scoped>

</style>

<template>
  <el-config-provider :locale="zhCn">
其它组件...
  </el-config-provider>
</template>

<script lang="ts" setup>
import zhCn from "element-plus/es/locale/lang/zh-cn";
</script>

<style scoped>

</style>

2、如何在原生js中按需使用element-plus：

*.js

import { ElMessage } from 'element-plus';
import 'element-plus/theme-chalk/el-message.css'

function fn(){
    ElMessage({
      message: '无数据',
      type: 'error'
    });
}

export default fn;