Milesight EM300-DI: LoRaWAN Pulse Counter for Meters

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 (°C)
      data.temperature = readInt16LE(bytes, i) / 10; i += 2;
    } else if (channel === 0x04 && type === 0x68) {   // humidity (%RH)
      data.humidity = bytes[i] / 2; i += 1;
    } else if (channel === 0x05 && type === 0x00) {   // GPIO status (0/1)
      data.gpio = bytes[i]; i += 1;
    } else if (channel === 0x05 && type === 0xc8) {   // pulse counter (UINT32 LE)
      data.pulse = readUInt32LE(bytes, i); i += 4;
    } else if (channel === 0x85 && type === 0x00) {   // GPIO + alarm flag
      data.gpio = bytes[i];
      data.gpio_alarm = bytes[i + 1]; i += 2;
    } else {
      break;
    }
  }
  return { data: data };
}

function readInt16LE(b, i) {
  var v = (b[i + 1] << 8) | b[i];
  return v > 0x7fff ? v - 0x10000 : v;
}

function readUInt32LE(b, i) {
  return ((b[i + 3] << 24) | (b[i + 2] << 16) | (b[i + 1] << 8) | b[i]) >>> 0;
}