Alexey Grinko
Sep 4, 2018 · 1 min read

It doesn’t necessarily re-render DOM. It just runs render() methods of all components in the subtree each time any prop changes, in order to see if any changes in DOM are needed. So if render methods are heavy, this might slow down performance.

DOM updates are optimized by React’s Virtual DOM and happen only when output of render() call changes, afaik.