Milesight VS340: LoRaWAN Desk & Seat Occupancy Sensor

function decodeUplink(input) {
  var bytes = input.bytes;
  var data = {};

  for (var i = 0; i < bytes.length; ) {
    var channel = bytes[i++];
    var type = bytes[i++];

    if (channel === 0x01 && type === 0x75) {          // battery (%)
      data.battery = bytes[i]; i += 1;
    } else if (channel === 0x03 && type === 0x00) {   // occupancy (0/1)
      data.occupancy = bytes[i] === 1 ? "occupied" : "vacant";
      i += 1;
    } else if (channel === 0xff) {                    // device info (join / power-on)
      i += deviceInfoLen(type);
    } else {
      break;
    }
  }
  return { data: data };
}

// 0xFF segment lengths from the published byte spec: version 1B, hw/fw/tsl 2B, SN 8B, class 1B.
function deviceInfoLen(type) {
  if (type === 0x16) return 8;                        // serial number
  if (type === 0x09 || type === 0x0a || type === 0xff) return 2; // hw / fw / tsl version
  return 1;                                           // ipso version, class, reset, status
}