Milesight VS351: LoRaWAN Mini Thermopile People Counter

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 === 0x67) {   // temperature (INT16 LE, /10 °C)
      data.temperature = readInt16LE(bytes, i) / 10; i += 2;
    } else if (channel === 0x04 && type === 0xcc) {   // total in / out (UINT16 LE each)
      data.total_in = readUInt16LE(bytes, i);
      data.total_out = readUInt16LE(bytes, i + 2);
      i += 4;
    } else if (channel === 0x05 && type === 0xcc) {   // period in / out (UINT16 LE each)
      data.period_in = readUInt16LE(bytes, i);
      data.period_out = readUInt16LE(bytes, i + 2);
      i += 4;
    } else if (channel === 0xff) {                    // device info (join / power-on)
      i += deviceInfoLen(type);
    } else {
      break;                                          // alarm / history / downlink frames
    }
  }
  return { data: data };
}

function readUInt16LE(b, i) {
  return ((b[i + 1] << 8) | b[i]) & 0xffff;
}
function readInt16LE(b, i) {
  var v = readUInt16LE(b, i);
  return v > 0x7fff ? v - 0x10000 : v;
}
// 0xFF segment lengths from the published byte spec: version 1B, hw/fw/tsl 2B, SN 8B, class/power 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, power, reset, status
}