Apples and Bananas but no Fruit

General
1

So I've made this simple setup.
I inject a Json msg "A" and this results in Global TEST "A". When I inject Json msg "B" I get the Global TEST "B" as result.
But what if I only wanted to change the amount Apples & Bananas without changing the payload "Fruit".
How would one change only one item in the TEST json msg without changing any of the other items? Can this be done directly?

NR_Fruit_Example
NR_Fruit_Example1346×252 122 KB

2

I don't understand what you mean. Please select those three nodes, Export them, and Paste them here, using the </> button at the top of the forum entry window when pasting. Then your question may make more sense.

3 
[
    {
        "id": "2cb8209b8102f7f2",
        "type": "inject",
        "z": "ada58d9a.2eab9",
        "name": "{\"payload\":\"fruit\",\"apples\":1,\"bananas\":2}",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "{\"payload\":\"fruit\",\"apples\":1,\"bananas\":2}",
        "payloadType": "json",
        "x": 2460,
        "y": 1500,
        "wires": [
            [
                "9a6bdd2aa2b28a0d"
            ]
        ]
    },
    {
        "id": "9a6bdd2aa2b28a0d",
        "type": "function",
        "z": "ada58d9a.2eab9",
        "name": "Set Payload to Global Set \"TEST\"",
        "func": "global.set(\"TEST\",msg.payload);\nreturn msg;",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 2840,
        "y": 1520,
        "wires": [
            []
        ]
    },
    {
        "id": "11a18762e4b937f5",
        "type": "inject",
        "z": "ada58d9a.2eab9",
        "name": "{\"apples\":4,\"bananas\":5}",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "{\"apples\":4,\"bananas\":5}",
        "payloadType": "json",
        "x": 2410,
        "y": 1540,
        "wires": [
            [
                "9a6bdd2aa2b28a0d"
            ]
        ]
    }
]
4

I sort of would like to do the same like a Dictionary in Python.
I have several items in a dictionary and I want to change only one item of the dictionary without changing any of the other items.

5

This should do what you want I think

// fetch previous object, default to empty object
let data = global.get("TEST") || {}
//merge old object into new
data = Object.assign(data, msg.payload);
// save it
global.set("TEST",data);
return msg;
6

Thanks Colin that is exactly what I needed.

7

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