LayerStyles / Appearance API

Hi, I'm trying to generate our color palette in sketch with react-sketchapp, from the documentation react-sketchapp supports Symbols and TextStyles, what about layer styles?

Example: I can run the color palette example, but each element of the palette only has direct styles applied to it, I'd like to use layer styles like this

Any pointers would be appreciated, otherwise I guess I'll have to use sketch's low level api?