Use Keyname of JSON Object

[
    {
        "id": "692f1ee1c1f78f40",
        "type": "function",
        "z": "c67cd75022d3e77b",
        "name": "function 25",
        "func": "var keys = Object.keys(msg.payload.MCP230XX_INT );\nvar varname = \"\";\n\nvar msgs = keys.map(function (key) {\n    varname = key;\n    global.set(varname, msg.payload.MCP230XX_INT[key] );\n\n    return { topic: key, payload: msg.payload.MCP230XX_INT[key] };\n});\n\nreturn [msgs];\n",
        "outputs": 1,
        "noerr": 0,
        "initialize": "",
        "finalize": "",
        "libs": [],
        "x": 510,
        "y": 280,
        "wires": [
            [
                "313c5bacb7743880"
            ]
        ]
    },
    {
        "id": "313c5bacb7743880",
        "type": "debug",
        "z": "c67cd75022d3e77b",
        "name": "debug 31",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 700,
        "y": 280,
        "wires": []
    },
    {
        "id": "5aa79583ec5b700c",
        "type": "json",
        "z": "c67cd75022d3e77b",
        "name": "",
        "property": "payload",
        "action": "",
        "pretty": false,
        "x": 350,
        "y": 280,
        "wires": [
            [
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            ]
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    },
    {
        "id": "5a8dfe0042ca16a5",
        "type": "inject",
        "z": "c67cd75022d3e77b",
        "name": "",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "{\"Time\":\"2023-08-01T12:57:00\",\"MCP230XX_INT\":{\"D14\":0,\"MS\":595440648}} ",
        "payloadType": "str",
        "x": 170,
        "y": 280,
        "wires": [
            [
                "a098936772ce6153",
                "5aa79583ec5b700c"
            ]
        ]
    },
    {
        "id": "a1890b5e956d0264",
        "type": "inject",
        "z": "c67cd75022d3e77b",
        "name": "",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": false,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "{\"Time\":\"2023-08-01T12:57:00\",\"MCP230XX_INT\":{\"D13\":1,\"MS\":595440648}} ",
        "payloadType": "str",
        "x": 170,
        "y": 180,
        "wires": [
            [
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                "a098936772ce6153",
                "5aa79583ec5b700c"
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]