[empthought]

React Native is native. It's nothing like trying to shoehorn rich client functionality and animations into a web view.

[vbezhenar]

JavaScript still much slower and more memory-hungry than Objective C.

[empthought]

Yes, and 99% of the code running in a React Native app is written in Objective-C, because they are native widgets and native libraries (often just the AppKit widget or a wrapper around it). That's why it's called React Native.

The JS runtime is only used to choreograph different native components. It's like a .xib or storyboard but with the ability to do logic. This code runs at user input speed so the relative performance characteristics are irrelevant.