react函数式组件怎么根据state来决定是否重新render

Question

类组件能通过shouldComponentUpdate来根据props和state决定是否render，函数式组件能通过React.memo来根据props决定render，但是怎么根据state来决定重新render呢，好像没看到hooks api有没有相关的

Answer 1

React.memo doesn’t compare state because there is no single state object to compare. But you can make children pure too, or even optimize individual children with useMemo.

参考： https://reactjs.org/docs/hook...

Answer 2

函数式组件何来的 state 呢？