Count and short objects in function node after uint16 modification

[panban-ux]

I have the following node:

[{"id":"f7844f50.7553c","type":"function","z":"11942aca.455835","name":"","func":"var lookup = {\n    73 : \"lemon\",\n    75 : \"pear\",\n    0 : \"apple\",\n    2 : \"orange\",\n    57 : \"kiwi\",\n    42 : \"grapefruit\",\n    1  : \"bad apple\",\n    255  : \"coconut\"\n   \n}\n\nvar result = {};\nfor (let i = 0; i < msg.payload.length - 1; i=i+4) {\n    let i1 = msg.payload[i];\n    let i2 = msg.payload[i+2];\n    let name = lookup[i1] || \"Unknown\" + i1;\n    result[name] = {\n        id: i1,\n        value: i2\n    }\n}\n\nmsg.payload = result;\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","x":760,"y":200,"wires":[["ad3a363a.68ba28"]]}]

In which i sent byte objects from my python application in this form to node-red [0,0,213,2,1,0,96,0,2,0,1,0]. The first 4 bytes are referred to a particular object (here apples) i have stored in a JSON file. More specifically the first byte in order 0 shows my class id of apples, second byte is an extension of first after uint16 conversion.

Now here is the purpose of this post, byte 3 here with a value of 213 is my object counting for apples, when this value gets beyond 255+1 and overflows it resets to 0. Forth byte here with a value of 2 is showing that iterated 2 times(counted already 2 full bytes) by 256+256. My question is how am i possible whenever i reach a point of overflow to add these values to the position of byte 3 and get the accurate count of my particular object.
Bear in mind that i inject this to TTN [ 0 725 1 96 2 1] in a byte array. As you will see my first object has 725 counts 256+256+213. The same goes from byte 5 and byte 9.
Original post is the following, but until that time i had objects up until 200 so i had to do a modification in my python code to facilitate more

Sort a payload array into object id's and into a UI

In short i've got this array [73,4,75,2,56,2,58,1,57,1,45,1] and some how i want to manipulate this data into a UI dashboard just to monitor how many times an object appears. In this case 73 is the id in my back end application for a lemon and it appears 4 times and so on. To recap this sequence [0 2 4 6 8 10] contains the id's of my objects and odd sequence in the middle is the count times of the object. Where do i start for example if my array gives eg [73,45] so to draw in my ui i got 45 le…

[E1cid]

If i understand correctly

let i2 = msg.payload[i+2]+(msg.payload[i+3]*255);

[Steve-Mcl]

@panban-ux

In which i sent byte objects from my python application in this form to node-red [0,0,213,2,1,0,96,0,2,0,1,0].

I never understand why people make things difficult for themselves.

Why not send something extensible and easy to convert like JSON?

[panban-ux]

@Steve-Mcl

Why not send something extensible and easy to convert like JSON?

Already in my python code i counted the entries then i converted them to a numpy array and then bytes object to TTN. My air medium is Lora Steve so i only have the luxury to send these numbers and not a JSON file.

[Steve-Mcl]

@panban-ux

My air medium is Lora Steve so i only have the luxury to send these numbers and not a JSON file.

ah my apologies.

[panban-ux]

Thanks anyway to both, you already had helped me in the original post and thanks to @E1cid for this current one