Its still crashing, here is the console, I am on a chromebook with google chrome. A brief google makes it seem like the output buffer has not enough frames... error is most likley a result of some sort of memory leak, using port.postMessage you could dump out some of the data to aid in troubleshooting. The null function or function signature mismatch error seems to be very vague and could mean a variety of things, I did not really want to put time into looking into it further, hope this helps., as for the "a listener indicated an asynchronous..." error, I used to get this all the time and be confused by what was wrong with my code, turns out its common with cross site requests and is a result of my browser extensions, not of concern for you (ignore the sensor, there was some info that I couldn't tell if was sensitive but suspected might be)