> The promise is simple and compelling: write once, ship twice. iOS and Android all in one shot

While this is certainly feasible (largely depending on the requirements of your app), it is important to clarify that RN never promised "write once ship twice".

RN's promise is "learn once, write anywhere", meaning that the technology and mental model is what transcends platforms, not the codebase itself.

Just wanted to make this clear so as to avoid any possible frustration for newcomers after the fact.