Leafletのマーカーをポップアップで表示したい

やりたいこと

いくつかのa要素があって、そのa要素をクリックすると該当のLeaflet内のマーカーが反応し、ポップアップで出るようにしたいです。

###現在、Leafletの仕様
外部のgeoJsonを読み込んでそこに緯度経度、popup、マーカー画像の名前等を保存しています。

###現状のソースコード

html
1<a href="#" id="hoge">東京</a>
2<a href="#" id="fuga">京都</a>

javascript
1
2$('#map').each(function () {
3
4    var tiles = L.tileLayer('https://{s}.tile.osm.org/{z}/{x}/{y}.png', {
5        maxZoom: 20,
6        attribution: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
7    });
8
9    var map = L.map('map')
10            .addLayer(tiles);
11
12    var markers = L.markerClusterGroup({
13      showCoverageOnHover: true,
14      spiderfyOnMaxZoom: false,
15      removeOutsideVisibleBounds: true,
16      disableClusteringAtZoom: 8
17    });
18
19
20
21httpObj = new XMLHttpRequest();
22httpObj.open("GET", "./geojson/hoge.geojson", true);
23httpObj.addEventListener('load', function(res){
24     const data = JSON.parse(res.currentTarget.response);
25
26    var geoJsonLayer = L.geoJson(data, {
27            onEachFeature: function (feature, layer) {
28                layer.bindPopup(feature.properties.popup);
29            },
30            pointToLayer: function(feature, latlng) {
31                var iconChange = L.icon({
32                    iconUrl: './geojson/'+ feature.properties.iconName +'.png',
33                    iconRetinaUrl: './geojson/'+ feature.properties.iconName2x +'.png',
34                    iconSize: [25, 41]
35                });
36                var iconDefalut = L.icon({
37                    iconUrl: './geojson/marker-icon-blue.png',
38                    iconRetinaUrl: './geojson/marker-icon-blue-2x.png',
39                    iconSize: [25, 41]
40                    //popupAnchor: [0, 20],
41                });
42
43
44             var m = L.marker(latlng, {icon: iconChange});
45             data.push(m);
46             return m;
47
48
49              if(feature.properties.iconName){
50                return L.marker(latlng, {icon: iconChange});
51              } else {
52                return L.marker(latlng, {icon: iconDefalut});
53              }
54            },
55            style: function (feature) {
56                return {
57                    color: feature.properties['stroke'],
58                    weight: feature.properties['stroke-width'],
59                    opacity: feature.properties['stroke-opacity']
60                };
61            }
62        });
63        markers.addLayer(geoJsonLayer);
64        map.addLayer(markers);
65        map.fitBounds(markers.getBounds());
66
67        function markerFunction(id){
68            for (var i in data){
69                var markerID = data[i].options.popup;
70                if (markerID == id){
71                    data[i].openPopup();
72                }
73            }
74        }
75
76        $("a").click(function(){
77            markerFunction($(this)[0].id);
78        });
79
80        map.addControl(new L.Control.Fullscreen({
81        title: {
82          'false': '最大化',
83          'true': '元に戻す'
84        }
85      }));
86
87        });
88
89        httpObj.send(null);
90        });

geojson
1{
2  "type": "FeatureCollection",
3  "features": [
4    {
5      "type": "Feature",
6        "title": "hoge",
7      "properties": {
8        "name": "あああ",
9        "popup": "<a href='' target='_blank'>hoge<br>fuga</a>",
10        "iconName": "marker-icon",
11        "iconName2x": "marker-icon-2x"
12      },
13      "geometry": {
14        "type": "Point",
15        "coordinates": [
16          138.922909,
17          37.135942
18        ]
19      }
20    },
21    {
22      "type": "Feature",
23        "title": "fuga",
24      "properties": {
25        "name": "いいい",
26        "popup": "<a href='' target='_blank'>hoge<br>fuga</a>",
27        "iconName": "marker-icon",
28        "iconName2x": "marker-icon-2x"
29      },
30      "geometry": {
31        "type": "Point",
32        "coordinates": [
33          138.914036,
34          37.114555
35        ]
36      }
37    }
38  ]
39}

###起きているエラー
現在は、aタグをクリックしても反応しない状態です。
コンソールエラーは、こんな感じででました。
Uncaught TypeError: Cannot read property 'popup' of undefined
at markerFunction ((index):974)
at HTMLAnchorElement.<anonymous> ((index):982)
at HTMLAnchorElement.dispatch (jquery-2.2.4.min.js:3)
at HTMLAnchorElement.r.handle (jquery-2.2.4.min.js:3)