1. props

this.props contains the props that were defined by the caller of this component. See Components and Props for an introduction to props.
In particular,this.props.children is a special prop, typically defined by the child tags in the JSX expression rather than in the tag itself.

也就是说Props应该是该组件的调用者使用的。

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2. state

The state contains data specific to this component that may change over time. The state is user-defined, and it should be a plain JavaScript object.
If you don't use it inrender(), it shouldn't be on the state. For example, you can put timer IDs directly on the instance.

state包含的数据应该都是用到render()里面的，如果不是用到render()，你可以考虑定义为props(需要外部调用者传进来)或者该组件的一个普通属性(例如组件内部用到的定时器等等)

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3 自定义的属性

组件用到的一些对象，不需要外部传入切不参与渲染，那么就可以定义为普通的组件属性。
例如组件用到了定时器

    setupInterval() {
        this.interval= setInterval(() => {
               //some stuff
        }, 5000)
    }