Use the build in share view from iOS to let the user share on Facebook and Twitter. It will use the users existing account without having to get new authorizations. You can even preset text, image and link for the share view.
Preview:
Download Details:
Author: doefler
Live Demo: View The Demo
Download Link: Download The Source Code
Official Website: https://github.com/doefler/react-native-social-share
License: MIT