How to access msg object per position

Dashboard
1

Hello,

I have a payload that looks that way:

payload: array[8]
0: object

  • Feldkennung: 104101
  • Feldname: "Projektnummer"
  • WertimFeld: "123 dummy"

I would like to access the values without knowledge of the payload object.

with msg.payload[x].Feldname i can get one spezific value.

I would like to have something like that: msg.payload[x].[y]

I have searched for a solution but i didnt find one.

maybe someone has a clue?

Dearly
Chorum

2

If y is a variable containing the name then you are nearly there, just take the dot out.
msg.payload[x][y]

3

Thats my Problem, the names could change (are unknown/different amounts of variables) and thats why i would like to use the position.

4

If you don't know what the payload is how do you expect to use the values?

In other words, What are you doing with the data?

5

Its the answer of an "dynamic" sql query. I ask for Objectdata and get answers from a pool of different datasets.
for instance: Objecttype Tire (diamater) , Objecttype Table (H,W,D/ amount tablelegs/ color ...)

So different amount of fields and different names.

The Answer is a list of Datasets with the same search criteria.

On the list i use checkboxes to filter the objects i want to use.
After that i put them on a html document for printing.

But i only need an access to the values without valuenames. :slight_smile:
Like with an array...

Atm i build a solution with asking for all the names to use them. But i hope there is a simplier solution.

6

Then you need to map the results and grab the key values.

Look up map and Object.values() on the mdn website.

Something like below in a function node after the SQL node...

msg.payload = msg.payload.map(e=> {
  return [...Object.values(e)]
})
return msg;

(Untested/written on phone)

7

Thanks !
Didnt work with map till today. I will try and will respond after that.

8

Works like a charm, thank you!

9

Hello,

i need to go a little bit more further...

With :
werte = msg.payload.map(e=> { return [...Object.values(e)] })

And:
namen = msg.payload.map(e=> { return [... Object.keys(e)] })

i have the keys and values in different maps.

now i would like to get both in one map, so i can loop through it and get keys and values.

i tried some versions of merging the maps but nothing worked.

may be creating a new map out of the two ?

For an example of the wished structure :

From

payload: array[8]
0: object

Feldkennung: 104101
Feldname: "Projektnummer"
WertimFeld: "123 dummy"

too

payload: array[8]
0: object

0:                  104101
1:                  "Projektnummer"
2:                  "123 dummy"
3:                  "Feldkennung"
4:                  "Feldname"
5:                  "WertimFeld"
10

That seems like an odd thing to want but anyhow, it looks like you just want to join the 2 arrays.

You can easily achieve that with the spread operator...

const werte = msg.payload.map(e=> { return [...Object.values(e)] });
const namen = msg.payload.map(e=> { return [...Object.keys(e)] });
msg.payload = [...werte, ...namen];
return msg;
11

The result:
mergedmap

i could work with that solution but may be there is a solution that works not like a push?

May be there is a simplier solution for my problem, i try to formulate my problem again.

I use a SQL query. As a result i get some datasets.
These Datasets differ in amount of entrys, names of the entrys and the values.
For every dataset i want to get the sructure key:value for all entrys.

if i get everything in an array with objects like:

0:                  104101
1:                  "Projektnummer"
2:                  "123 dummy"
3:                  "Feldkennung"
4:                  "Feldname"
5:                  "WertimFeld"

i can get everything i want dynamicly and in loops without knowing what kind of objects i get from my sql query...

may be i think too complicated ?

12

My point was that format is terrible. An object or array of objects is far more suited.

Try these 3 demos - see what suits you...

[
    {
        "id": "eb890c42660627b1",
        "type": "inject",
        "z": "eb3bd3ff.33367",
        "name": "fake DB data",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "[{\"Feldkennung\":104101,\"Feldname\":\"Projektnummer\",\"WertimFeld\":\"123 dummy\"},{\"Feldkennung\":104101,\"Feldname\":\"Projektnummer\",\"WertimFeld\":\"123 dummy\",\"AnotherFeld\":\"another value\"}]",
        "payloadType": "json",
        "x": 920,
        "y": 660,
        "wires": [
            [
                "7eb4c0d1f00403b5",
                "883b851d53d857a2",
                "33aead0e2507b653"
            ]
        ]
    },
    {
        "id": "7eb4c0d1f00403b5",
        "type": "function",
        "z": "eb3bd3ff.33367",
        "name": "what you are after",
        "func": "const werte = msg.payload.map(e => { return [...Object.values(e), ...Object.keys(e)] });\nmsg.payload = werte.flat(2);\nreturn msg;\n",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 1150,
        "y": 600,
        "wires": [
            [
                "8e518250ae8f4e2f"
            ]
        ]
    },
    {
        "id": "8e518250ae8f4e2f",
        "type": "debug",
        "z": "eb3bd3ff.33367",
        "name": "",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 1510,
        "y": 600,
        "wires": []
    },
    {
        "id": "883b851d53d857a2",
        "type": "function",
        "z": "eb3bd3ff.33367",
        "name": "a better way",
        "func": "const werte = msg.payload.map(e => Object.entries(e));\nmsg.payload = werte.flat(1);\nreturn msg;\n",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 1130,
        "y": 660,
        "wires": [
            [
                "38e4234858c1392e"
            ]
        ]
    },
    {
        "id": "33aead0e2507b653",
        "type": "function",
        "z": "eb3bd3ff.33367",
        "name": "much better (keeps name+value together)",
        "func": "const data = msg.payload;\nconst result = [];\nlet rowNo = 0;\ndata.forEach(d => {\n    rowNo++;\n    let nvarr = Object.entries(d);\n    nvarr.forEach(e => {\n        const nvpair = {\n            row: rowNo,\n            field: e[0],\n            value: e[1]\n        }\n        result.push(nvpair)\n    })\n})\nmsg.payload = result;\nreturn msg;\n",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 1220,
        "y": 720,
        "wires": [
            [
                "fd54add26e56f888"
            ]
        ]
    },
    {
        "id": "38e4234858c1392e",
        "type": "debug",
        "z": "eb3bd3ff.33367",
        "name": "",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 1510,
        "y": 660,
        "wires": []
    },
    {
        "id": "fd54add26e56f888",
        "type": "debug",
        "z": "eb3bd3ff.33367",
        "name": "",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 1510,
        "y": 720,
        "wires": []
    }
]
13

i will try to understand the code and will respond after i tried that.

thanks!

14

On demo 1 & 2 i get:"werte.flat is not an function". I cant see whats wrong there.
But i learned the method .flat :slight_smile:

Demo 3 works and seems to be the solution.

I will try that solution and will respond after that. May be tomorrow.

Thanks for your time!

15

You must be on node-js V10 or below. compatibility report

I would definitely recommend upgrading as that is EOL / out of support.

V14 LTS (or even V16) is now preferable.

16

I needed to use an other option, but i learned something new.

Thanks!

17

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