I have not been able to find a solution to Touch ID using React-Native. I am only able to sign in to the app using a finger enrolled in the device, but how can I actually enroll a new finger to use ONLY for authenticating with that app?
Definitely, behind the React Native libraries, there are Android/iOS native codes. and in both of them, the given device API allows the developers to use the fingerprint saved data to authenticate. you cannot get the fingerprint data and keep it on your application or server. for more information, you can see this post.
So, because of the limitation on the native side, the React Native cannot get the fingerprint data.
It is not possible.