I haven't used it, but it seems like it'd probably allow you to use Espruino/other devices in Home Assistant. It seems to need config using a config file though so it's perhaps not super-easy to use
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.
There is this:
I haven't used it, but it seems like it'd probably allow you to use Espruino/other devices in Home Assistant. It seems to need config using a config file though so it's perhaps not super-easy to use