I don't think anything like that is implemented currently in gadgetbridge?
Well, Gadgetbridge does provide some Pebble support, but I'm not sure how easy it would be to repurpose that. That's an interesting thought though - rather than trying to include JSpath you could just include some JS to run inside Gadgetbridge.
I'm not sure how sensible it'd be to run Espruino, but Android does seem to have a few ways of running JS
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Well, Gadgetbridge does provide some Pebble support, but I'm not sure how easy it would be to repurpose that. That's an interesting thought though - rather than trying to include JSpath you could just include some JS to run inside Gadgetbridge.
I'm not sure how sensible it'd be to run Espruino, but Android does seem to have a few ways of running JS