There was talk about being able to run Swift apps on Android in the future. If it becomes official i think the community around swift would be pretty large.
About that... Naaa.
While i appreciate diversity, this is non gonna happen...
Swift is too different to be a serious alternative
.. or Ionic, or Cordova, or PhoneGap.
Those are just webviews.
Nativescript, titanium, xamarin, or qt is where react native would be categorized with