Planning a React Native and React web app

Hello!
If I am creating a website in React, would I have to re-write everything in React Native if I were to create a mobile app also?
Or is there a way for them to share common UI components etc.?

Trying to plan before I get started. Doing Mosh’s React Native fundamentals course currently.

Regards,
Sal

Hi there.
I am having the same situation here, and I am looking for available alternatives.
Finally, what did you do with your RN project?