Derived State: Fully uncontrolled component with a key

Hi,

In the article You Probably Don't Need Derived State, one of the recommended ways to avoid deriving state from props, is to have "Fully uncontrolled component with a key".

However, there is no way to actually force the user to provide a 'key' property to the component, since declaring it in propTypes as "key: PropTypes.any.isRequired" won't work, because it's value is always 'undefined', which leads to a warning message:

Warning: MyComponent: key is not a prop. Trying to access it will result in undefined being returned. If you need to access the same value within the child component, you should pass it as a different prop.

And without declaring the 'key' prop type, we cannot assume, that the user will use the component in a proper manner.

How to mitigate this?

从链接的“ You Probably Don't Need Derived State”文章以及报告的访问 key 时出现的 PropTypes 警告开始。确定文档是否需要澄清带有 key 的完全非受控组件；完成标准是文章解释一种有效的缓解方法，或明确记录这一限制。