因为vue3.0不支持element-ui的安装，所以想要使用element组件，只能安装element-plus

1、命令行安装依赖

# 选择一个你喜欢的包管理器

# NPM
$ npm install element-plus --save

# Yarn
$ yarn add element-plus

# pnpm
$ pnpm install element-plus

第一种方式：在main.js中引入（完整引入方式）

import { createApp } from 'vue'
import App from './App.vue'
import './registerServiceWorker'
import router from './router'
import store from './store'
import ElementPlus from 'element-plus'
import 'element-plus/dist/index.css'

createApp(App).use(store).use(router).use(ElementPlus).mount('#app')

第二种方式：vue.config.js中引入（按需导入方式）

const { defineConfig } = require('@vue/cli-service');
const AutoImport = require('unplugin-auto-import/webpack');
const Components = require('unplugin-vue-components/webpack');
const { ElementPlusResolver } = require('unplugin-vue-components/resolvers');

module.exports = defineConfig({
  transpileDependencies: true,
  configureWebpack: {
    plugins: [
      AutoImport({
        resolvers: [ElementPlusResolver()],
      }),
      Components({
        resolvers: [ElementPlusResolver()],
      }),
    ],
  }
})