That is a very tall claim to make without any citations. All the cross-platform toolkits lag behind native swift/java apps by at least some margin, and the claim that JS indistinguishable from swift/Java is highly questionable.
I respect RN and the engineering behind it, however how can it beat the raw, on-metal performance of Swift/Java? I'm not talking about CRUD/TODO list apps like https://li.st, but performance critical apps like Spotify etc. Facebooks own apps are written in native code, IIRC.
I would love to be proven wrong here, and it would be great if you can provide some sources.
They are written in React Native. See: https://facebook.github.io/react-native/showcase.html