Assuming the ESP32 is advertising, you should be able to use something like:
NRF.setScan(function(d) { if (d.addr=="...") LED.write(d.rssi>-70); });
You'll need to change the address and probably the RSSI value as well, but that should be a good start :)
@Gordon started
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.
Assuming the ESP32 is advertising, you should be able to use something like:
You'll need to change the address and probably the RSSI value as well, but that should be a good start :)