JSFiddle - React, Tailwind, and code Playground

JavaScript

var data = {    "hits": [
      {
        "_index": "selfexclusion",
        "_type": "selfexclusion",
        "_id": "leovegas,leovegas,UKGC,202724724",
        "_source": {
          "id": "leovegas,leovegas,UKGC,202724724",
          "playerKey": {
            "operator": "leovegas",
            "brand": "leovegas",
            "license": "UKGC",
            "playerUid": "202724724"
          },
          "playerDetails": {
            "firstName": "Diane",
            "lastName": "beauchamp",
            "email": "[email protected]",
            "dateOfBirth": "1946-09-12",
            "postCode": "TN38 9DE",
            "mobilePhone": "00447599210182"
          },
          "startDate": "2017-03-03 18:53:55",
          "endDate": "2067-03-03 18:53:54",
          "reason": "UK_TIMEOUT_BY_BO"
        }
      },
      {
        "_index": "selfexclusion",
        "_type": "selfexclusion",
        "_id": "leovegas,leovegas,UKGC,203660309",
        "_source": {
          "id": "leovegas,leovegas,UKGC,203660309",
          "playerKey": {
            "operator": "leovegas",
            "brand": "leovegas",
            "license": "UKGC",
            "playerUid": "203660309"
          },
          "playerDetails": {
            "firstName": "Darran",
            "lastName": "Woffinden",
            "email": "[email protected]",
            "dateOfBirth": "1969-09-27",
            "postCode": "Ts3 6jh",
            "mobilePhone": "00447453944977"
          },
          "startDate": "2017-11-18 10:20:54",
          "endDate": "2022-11-18 10:20:21",
          "reason": "REASON_2"
        }
       }
        ]};

var result = [];
getNames(data, "playerDetails");
document.write("result: " + result.join(", "));

function getNames(obj, name) {
    for (var key in obj) {
        if (obj.hasOwnProperty(key)) {
            if ("object" == typeof(obj[key])) {
                getNames(obj[key], name);
            } else if (key == name) {
      //      		result += obj[key];
...