This to me is where the real error is. Why would an EOF on the serial port be seen when that can only come from the Arduino? What if your Arduino FTDI chip has gone bad?
Working on element:<Idle|WPos:0.000,0.000,0.000|Bf:15,128|FS:0,0|WCO:0.000,0.000,0.000>, index:0
2017/04/22 14:35:08 bufferflow_grbl.go:210: OnIncomingData() end.
2017/04/22 14:35:09 serialport.go:187: Hit end of file on serial port
2017/04/22 14:35:09 serialport.go:193: EOF
The other question is, after seeing all of these posts from you, did your websocket ever actually disconnect? It looks like it never does, but you were saying it was disconnecting the websocket. Could you post a screenshot of what ChiliPeppr looks like after you have seen this error just to make sure it’s simply the serial port disconnecting and not the actual websocket between SPJS and the browser disconnecting?
After these errors the tick vanishes from the console. The entry for the serial port remains. Sometimes there is a red triangle there.
I think an occasional error from the ftdi chip seems very unlikely. It is a genuine arduino and i think actually uses an atmel chip as the USB interface.
Ok, so it sounds like your websocket has been fine all along. Do you have a 2nd Arduino to try out? It can’t hurt. It could even be a bad USB cable. What if just wiggling/vibration causes the USB cable to get loose enough to drop serial port?
The more I think about this, the more I think this is hardware layer where something is literally dropping your serial port at OS layer and that this is not ChiliPeppr or SPJS. Getting an EOF after a WPos line should not happen. The EOF is coming in from the OS because it stops seeing the serial port. That sounds like hardware.