rendering twice

[johnico]

when i use this sample a component is rendering twice. even if is a sample one, how can I fix it?
react 16.13+

[tswistak]

Hi,
I've upgraded React to the newest version in the sample and debugged it - rendering for "Hello" component is executed only one time (tested on Firefox and Chrome). If you could provide a reproducible sample showing double render I'll try to help more.