To be honest the standard nRF52832DK build might well work on it as-is - on other devices Nordic have tended to use the same pins for the UART, so if they've done the same on here you'd be sorted.
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.
Looks like a neat little device!
To be honest the standard nRF52832DK build might well work on it as-is - on other devices Nordic have tended to use the same pins for the UART, so if they've done the same on here you'd be sorted.