Do animations run in UI or JS thread in React Native?

[imsam67]

I'm evaluating animation libraries for my React Native projects and I was wondering if animations produced by react-spring run in the UI or JavaScript thread in React Native projects.

One library I've looked at is react-native-reanimated and I understand, unlike the animation built-into react-native, the react-native-reanimated animations run in the UI thread which seems like the way to go for smoother animations. Which thread do react-spring animations run in react-native projects?

[aleclarson]

In the JS thread currently, but I plan to integrate Reanimated for my next project sometime this year.