Callback on nested setState doesn't called with update state

[edimitchel]

Hi !

On this issue (#556), I discuss with @JoviDeCroock about an issue when I use setState on the componentWillDidMount.

My issue concerns the callback of a nested setState (into another setState callback). The state inside the nested callback is not updated (was it called at the same time as the parent callback ?). This weird way to handle state is not mine, it's a legacy code, but it's usefull for some SSR needs (we use same components for React, React with SSR and Preact).

You can see the wrong behavior on this codesandbox.