Fantastic find! You are absolutely correct, I made an assumption that it would work and unfortunately have no means to try it (lack the hardware).
I appreciate you digging into the code and finding the problem!
Edit: I looked through the interval program for the RPi and you are absolutely correct, there is no pn.js. I updated the code to use /vs which is available in the RPi along with the normal OS. I am sure other problems exist and would appreciate more feedback. Thank you!