照着官方文档

1.下载babel-plugin-component依赖项

npm install babel-plugin-component -D

2.添加/修改.babelrc文件

{
  "presets": [["es2015", { "modules": false }]],
  "plugins": [
    [
      "component",
      {
        "libraryName": "element-ui",
        "styleLibraryName": "theme-chalk"
      }
    ]
  ]
}

然后就报错 Error: Cannot find module 'babel-preset-es2015
既然缺少这个依赖，那么

npm i babel-preset-es2015 -S

又报错了 Error: plugin/preset files are not allowed to export objects

疯狂百度，找到了解决方案:

1.安装@babel/preset-env；项目目录下，运行命令行

npm i @babel/preset-env --save-dev

2.修改.babelrc文件，把es2015改成@babel/preset-env

{
  "presets": [["@babel/preset-env", { "modules": false }]],
  "plugins": [
    [
      "component",
      {
        "libraryName": "element-ui",
        "styleLibraryName": "theme-chalk"
      }
    ]
  ]
}

3.也可以在babel.config.js中的修改

module.exports = {
  "presets": [["@babel/preset-env", { "modules": false }]],
  "plugins": [
    [
      "component",
      {
        "libraryName": "element-ui",
        "styleLibraryName": "theme-chalk"
      }
    ]
  ]
}

参考自
作者：I-T枭
链接：vue 给UI库添加按需加载时启动项目时 babel-preset-es2015 报错