RH
как "так"?
Мне интересно просто как он берет размеры DOM элемента
Component renders for the first time.https://reacttraining.com/blog/useEffect-is-not-the-new-componentDidMount/
The return value of render() is used to mount new DOM.
componentDidMount fires and set's state immediately (not in an async callback)
The state change means render() is called again and returns new JSX which replaces the previous render.
The browser only shows the second render to avoid flicker.
