React官方文档，Handling Event部分有一段不明白

Question

老师，您好，看官方文档时候，有一段，没看懂，您能帮忙给举个例子么，谢谢

https://facebook.github.io/react/docs/handling-events.html

Handling Events部分的末尾，有这样一段

The problem with this syntax is that a different callback is created each time the LoggingButton renders. In most cases, this is fine. However, if this callback is passed as a prop to lower components, those components might do an extra re-rendering. We generally recommend binding in the constructor or using the property initializer syntax, to avoid this sort of performance problem.

我想不到一个合适的例子来验证这句话，麻烦老师了，谢谢

Answer 1

Parry 2017-04-17 10:20:14

主要的意思是 当 向子组件传递回调的时候，会导致子组件的重新渲染（re-rendering），可能引起性能问题。

• 提问者 慕粉3858555 #1

  嗯，我明白，可是我想不到例子，我写了几个例子，向子组件传递回调，都不会引起子组件的重新渲染。能麻烦您帮忙想个可以引起子组件重新渲染的例子么，谢谢.