{
  "plugins": [
    "@babel/plugin-transform-arrow-functions",
    "@babel/plugin-transform-classes",
    [
      "@babel/plugin-proposal-decorators",
      {
        "legacy": true
      }
    ],
    [
      "@babel/plugin-proposal-class-properties",
      {
        "loose": true
      }
    ]
  ]
}

使用装饰器语法插件时，如果不配置 @babel/plugin-proposal-class-properties，无法打印出使用装饰器语法添加的属性。