Vue報錯（Property or method "xxx" is not defined on the instance but referenced during render.）

報錯如下：
Property or method “xxx” 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.
屬性或方法“xxx”不是在實例上定義的，而是在呈現期間引用的。通過初始化該屬性，確保該屬性是反應性的，無論是在data選項中，還是在基於類的組件中。

原因:
“xxx”在template或方法中使用了，但是沒有在data中定義

解決：

export default {
 data(){
  return{
    xxx:""
  }
 },
}