- Property or method "index" is not defined on the instance but referenced during render. Make sure that this property is reactive, either in the data option, or for class-based components, by initializing the property.
属性或方法“index”不是在实例上定义的，而是在呈现期间引用的。通过初始化该属性，确保该属性在数据选项或基于类的组件中是响应的。
解决办法：
- Unknown custom element: <transition-grounp> - did you register the component correctly? For recursive components, make sure to provide the "name" option.
(found in <Root>)
未知自定义元素：<transition grounp>-是否正确注册了该组件？对于递归组件，请确保提供“name”选项。
（在<root>中找到）
解决方法：我自己的标签名写错了，应该是<transition-group>
- App.vue单文件组件代码是黑白色
解决方法：下载vuter插件，按住Ctrl+shift+x，在框中输入vuter，然后点击install，安装好后，.App单文件组件代码颜色就可以了
