How to retrieve an array from within a JSON array? OpenstreetMap Nominatim Lookup

I would like to get the latitude and longitudes of an address from the OpenstreetMap Server. I use the following code:
The URI https://nominatim.openstreetmap.org/search/Keizersgracht%202,%20Amsterdam?format=json

gives me the following JSON output:

[
    {
        "place_id": 29597926,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2729940028,
        "boundingbox": [
            "52.3654887",
            "52.3655887",
            "4.8878076",
            "4.8879076"
        ],
        "lat": "52.3655387",
        "lon": "4.8878576",
        "display_name": "489B-2, Keizersgracht, Grachtengordel, Amsterdam, Noord-Holland, Nederland, 1017DM, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    },
    {
        "place_id": 29345477,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2722023917,
        "boundingbox": [
            "52.3669115",
            "52.3670115",
            "4.8842236",
            "4.8843236"
        ],
        "lat": "52.3669615",
        "lon": "4.8842736",
        "display_name": "460-2, Keizersgracht, Grachtengordel, Amsterdam, Noord-Holland, Nederland, 1016GE, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    },
    {
        "place_id": 29416200,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2729939619,
        "boundingbox": [
            "52.3664731",
            "52.3665731",
            "4.8847569",
            "4.8848569"
        ],
        "lat": "52.3665231",
        "lon": "4.8848069",
        "display_name": "470-2, Keizersgracht, Grachtengordel, Amsterdam, Noord-Holland, Nederland, 1017EG, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    },
    {
        "place_id": 29866709,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2737809901,
        "boundingbox": [
            "52.3635475",
            "52.3636475",
            "4.898591",
            "4.898691"
        ],
        "lat": "52.3635975",
        "lon": "4.898641",
        "display_name": "766-2, Keizersgracht, Grachtengordel, Amsterdam, Noord-Holland, Nederland, 1017EB, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    },
    {
        "place_id": 29285837,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2722023414,
        "boundingbox": [
            "52.3674621",
            "52.3675621",
            "4.8847902",
            "4.8848902"
        ],
        "lat": "52.3675121",
        "lon": "4.8848402",
        "display_name": "405-2, Keizersgracht, Negen Straatjes, Amsterdam, Noord-Holland, Nederland, 1016EK, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    },
    {
        "place_id": 29667468,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2729940808,
        "boundingbox": [
            "52.3647928",
            "52.3648928",
            "4.8890486",
            "4.8891486"
        ],
        "lat": "52.3648428",
        "lon": "4.8890986",
        "display_name": "523-2, Keizersgracht, Grachtengordel, Amsterdam, Noord-Holland, Nederland, 1017DP, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    },
    {
        "place_id": 30045384,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2737809134,
        "boundingbox": [
            "52.3639034",
            "52.3640034",
            "4.8977648",
            "4.8978648"
        ],
        "lat": "52.3639534",
        "lon": "4.8978148",
        "display_name": "701-2, Keizersgracht, Grachtengordel, Amsterdam, Noord-Holland, Nederland, 1017DW, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    },
    {
        "place_id": 29337731,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2721355336,
        "boundingbox": [
            "52.3756178",
            "52.3757178",
            "4.8857254",
            "4.8858254"
        ],
        "lat": "52.3756678",
        "lon": "4.8857754",
        "display_name": "172A-2, Keizersgracht, Grachtengordel, Amsterdam, Noord-Holland, Nederland, 1015CZ, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    },
    {
        "place_id": 29077463,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2721355435,
        "boundingbox": [
            "52.3791909",
            "52.3792909",
            "4.8890042",
            "4.8891042"
        ],
        "lat": "52.3792409",
        "lon": "4.8890542",
        "display_name": "18-2, Keizersgracht, Grachtengordel, Amsterdam, Noord-Holland, Nederland, 1015CP, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    },
    {
        "place_id": 29212365,
        "licence": "Data © OpenStreetMap contributors, ODbL 1.0. https://osm.org/copyright",
        "osm_type": "node",
        "osm_id": 2721354960,
        "boundingbox": [
            "52.3754143",
            "52.3755143",
            "4.8864475",
            "4.8865475"
        ],
        "lat": "52.3754643",
        "lon": "4.8864975",
        "display_name": "155-2, Keizersgracht, Grachtengordel, Amsterdam, Noord-Holland, Nederland, 1015CL, Nederland",
        "class": "place",
        "type": "house",
        "importance": 0.32100000000000006
    }
]

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This is my code to get the data:

        /**
         * @description Looks up the coordinates based on an address
         * @returns {text} coordinates of an input address
         */
        this.lookupCoordinates = function(anAddress) {
          boundingBox: [];
           var url = "http://nominatim.openstreetmap.org/search/" + encodeURI(anAddress) + "?format=json";
           /* Get the data */
           $.get(url, function (data) {
             var obj = $.parseJSON(data); // 
                 boundingBox = obj.data[0].boundingbox;
              }
           );
           console.log(boundingBox);
          };

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My code does not yet work as expected. As you can see, some addresses return more than boundingbox.

How do I get the first array item's bounding box with JavaScript so that I can return the lat/lng?