Flow set "array error" using mqtt topic

General
1

Hi.

I am trying to save a thermostat mode to a flow variable using the msg.topic but it does not work as expected.

Flow:

flow
flow2331Ă—606 177 KB

Result:

result
result490Ă—542 32.4 KB

How can i save it based on the MQTT adress without getting all those array enteries as well?

This is my example flow:

[{"id":"d8f143e9.eb063","type":"function","z":"82add03.b9a433","name":"","func":"//Get adress and build flow variable name \nvar address = msg.topic.split(\"/\")[2];\nvar newname = \"hdl.fh.\" + address + \".textmode\"\n\n//Save msg to flow variable\nflow.set (newname, msg.payload)\n\n//Debug\nmsg.address = address\nmsg.newname = newname\n\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":360,"y":120,"wires":[["ca252047.e559a"]]},{"id":"ca252047.e559a","type":"debug","z":"82add03.b9a433","name":"2","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":530,"y":120,"wires":[]},{"id":"dbbd3792.f6fd88","type":"inject","z":"82add03.b9a433","name":"Test input msg: Normal","props":[{"p":"topic","vt":"str"},{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"hdl/fh/1.106/textmode/set","payload":"normal","payloadType":"str","x":140,"y":80,"wires":[["d8f143e9.eb063","2bfddbe0.c8dea4"]]},{"id":"de39039.e93a9","type":"inject","z":"82add03.b9a433","name":"Test input msg: Day","props":[{"p":"topic","vt":"str"},{"p":"payload"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"hdl/fh/1.106/textmode/set","payload":"day","payloadType":"str","x":130,"y":140,"wires":[["d8f143e9.eb063","2bfddbe0.c8dea4"]]},{"id":"2bfddbe0.c8dea4","type":"debug","z":"82add03.b9a433","name":"1","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":350,"y":200,"wires":[]}]
2

It's flow.set("newname", msg.payload)
With quotes around the variable name, same with flow.get

3

You issue is the numbers in the path are being interpreted as array elements

You will need to DIY this one...

const data = {
    hdl: flow.get("hdl") || {}
}

//Get adress and build flow variable name 
const address = msg.topic.split("/")[2];
const newname = "hdl.fh." + address + ".textmode";
const value = msg.payload;


setValue(data, newname, value);
flow.set("hdl", data.hdl);

//Debug
msg.address = address
msg.newname = newname

return msg;


/**
* @param {object} obj
* @param {string} path
* @param {any} value
*/
function setValue(obj, path, value) {
    var a = path.split('.')
    var o = obj
    while (a.length - 1) {
        var n = a.shift()
        if (!(n in o)) o[n] = {}
        o = o[n]
    }
    o[a[0]] = value
}

image

1 Like
4

Thanks that worked great. I would never be able to get that working alone, and still dont understand how that code works.

5

In simple terms, the setValue splits hdl.fh.1.106.textmode by "." into an array then loops through them setting the object obj parameters, creating a new object where none exists & on the last element, setting the value.

6

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