Can’t able to access element from Object in ReactJs

I have 4 lines to code

console.log(Object.keys(data));
console.log(data);
console.log(data['createTs']);
console.log(data.createTs);

output for 1st line :

[
    "supplierName",
    "supplierNbr",
    "itemNbr",
    "category",
    "subCategory",
    "receivingNodesInbound",
    "whseOrderIds",
    "orderType",
    "overviewStatus",
    "fromNode",
    "orderSubTypes",
    "itemDesc",
    "importOrDomestic",
    "event",
    "systemCreatorId",
    "createBy",
    "channelMethod",
    "source",
    "freight",
    "singleCreateTs"
]

Output for 2nd line:

{
    "supplierName": "",
    "supplierNbr": "",
    "itemNbr": "",
    "category": [],
    "subCategory": [],
    "receivingNodesInbound": "",
    "orderType": [
        "PO"
    ],
    "overviewStatus": [],
    "orderSubTypes": [],
    "systemCreatorId": [],
    "createBy": "",
    "channelMethod": [],
    "source": [],
    "orderIds": [],
    "hostNbr": [],
    "lineStatuses": [],
    "orderSubTypeList": [],
    "categories": [],
    "createTs": {
        "startDate": "NaN-NaN-NaN"
    }
}

3rd and 4th line is giving “undefined”.
I couldn’t understand why its giving undefined. How can I access createTs from data object?