A Crelay NodeJS Daemon
Was Part of a Project that used Relays to switch Stuff on Off via a WebInterface using websockets.
This is deprecated as i think today 2020 you can easy code your own wrapper around crelay 's api's if you need them i think the future will be to use the Browser for that and maybe wasm while it is not need i think. There exists the WebSerial Api which offers direct access to most Relay Cards.