Possible conceptual pitfall when discussing accessing a state variable set in a previous render

Hi there!

In this section: https://react.dev/learn/you-might-not-need-an-effect#adjusting-some-state-when-a-prop-changes

It took me a while to understood that prevItems would not be changed until setItems was invoked on it. What tripped me there was that I thought that useState(X) always set items to X on every re-render. Once I understood that prevItems is set to X only when the state is initialized, everything is clear.

This might perhaps be a good place in the docs to clarify (either on a couple of sentences or on its own Pitfall section) that setState will only initialize a value, but not update it during a re-render.

I take this opportunity for congratulating the team on the new React docs. There are one of the best technical documentation pieces I've read in my entire career. 🚀

阅读 React 文档中链接的“Adjusting some state when a prop changes”部分，并检查其中对跨渲染过程的 useState 和 setState 的解释。完成标准是该部分清楚地区分状态的初始初始化与后续更新，并回应所报告的误解。