详细解决Vue的警告：Property or method “xxx“ is not defined on the instance but referenced during render

1. 复现错误

今天模拟下单的操作，运行使用Vue刚写好的代码，如下图所示：

从页面并没有看出任务错误，当我们使用F12打开控制台，却报出如下错误：

即Property or method "name" 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。

2. 分析错误

控制台虽然显示红色的异常，但Vue其实报出的并非错误，而是警告：Vue Warn