uni - app - Property or method “toJSON“ is not defined on the instance but referenced during render.

完整报错

## SEO

[Vue warn]: Property or method "toJSON" 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. See: https://vuejs.org/v2/guide/reactivity.html#Declaring-Reactive-Properties.

解决方法

在当前报错页面，methods 方法中加入以下代码：

toJSON(){}

如下示例(什么都不需要写)：