The Client ID you get needs to be hard-coded into the React-Native application
The essential boilerplate to authenticate users on your React-Native app
Alexis Mangin

I found your post and we followed your advice when programming the very first prototype of our mobile App, however I’m worried about this point, hard-coding the client ID into the app seems like a liability, is this value is accessible by a potential hacking of the app? I’m mostly concerned because of this article mentioned in the oficial OAuth2 documentation