What about porting the Arduino code to the esp8266/esp32 ? powerful chip + huge network.
Altough as a prototyping platform, i can understand how javascript would be more appealing. And for production, even by startup, the Arduino is far from ideal, mbed is much better.
shameless plug: portable JavaScript+C programming environment for esp8266/esp32/cc3200/RPi https://github.com/cesanta/smart.js. Supports over the air updates (OTA) both and rapid development and updating your device fleet.
Altough as a prototyping platform, i can understand how javascript would be more appealing. And for production, even by startup, the Arduino is far from ideal, mbed is much better.