Payload formatter runtime error messages

EFthings01 · May 7, 2025, 2:10pm

Dear forum members,

I had some trouble using a payload formatter for the Milesight UC300. This is a Lora-node that can read multiple direct inputs and up to 32 modbus sensors. The UC300 was equipped with 6 sensors, but only the first three where reported by the payload decoder.

After some research I found that there is a little yellow traffic sign in the source code of the payload formatter installed from the repository. This says: Too many errors (76% scanned). The repository version has about 7 kB and 195 lines of code and this is the only error hint.

There is another version of the formatter on github:

github.com/Milesight-IoT/SensorDecoders

UC_Series/UC300/UC300_Decoder.js

main

/**
 * Payload Decoder
 *
 * Copyright 2025 Milesight IoT
 *
 * @product UC300
 */
var RAW_VALUE = 0x00;

// Chirpstack v4
function decodeUplink(input) {
    var decoded = milesightDeviceDecode(input.bytes);
    return { data: decoded };
}

// Chirpstack v3
function Decode(fPort, bytes) {
    return milesightDeviceDecode(bytes);
}

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This has about 550 lines of code and 20 kB. It shows some more errors. The last one was again: Too many errors (32% scanned). This version seems to work properly.

Can anybody explain, what the message means and why I get the message as the first and only error? It seems the repository formatter somehow crashes at runtime, but this is not reported. At least, I cannot see any reason why the payload is not processed completely.

Is there any way to debug a payload decoder? I tried to test the decoder on some other JS playground, but all code runs properly here. So, it seems there are some differences in the environment.

descartes · May 7, 2025, 6:56pm

Yup, you can do it on your desktop computer, here’s an example: TypeError: Value is not an object: undefined at apply (native) when trying to decode payload - #4 by descartes

There are, as detailed in the docs: JavaScript | The Things Stack for LoRaWAN