过滤mapbox markcluster

Question

我正在尝试使用markerclustergroup中的自定义图标过滤地图框标记。我似乎无法让过滤器在markerclustergroup上运行。以下是代码的相关部分：

var filters = document.getElementById(‘filters’);
var checkboxes = document.getElementsByClassName(‘filter’);

var markers = L.mapbox.featureLayer()
   .setGeoJSON(geojson);

var markercluster = new L.MarkerClusterGroup();

markers.on(‘layeradd’, function(e) {

// Create custom markers

   var marker = e.layer,
   feature = marker.feature;
   marker.setIcon(L.icon(feature.properties.icon));

 function change() {
 // Find all checkboxes that are checked and build a list of their values
    var on = [];
    for (var i = 0; i < checkboxes.length; i++) {
        if (checkboxes[i].checked) on.push(checkboxes[i].value);
    }
    // The filter function takes a GeoJSON feature object
    // and returns true to show it or false to hide it.
    markers.setFilter(function (f) {
        // check each marker’s symbol to see if its value is in the list
        // of symbols that should be on, stored in the ‘on’ array
        return on.indexOf(f.properties[‘marker-symbol’]) !== -1;
    });
    return false;
}

// When the form is touched, re-filter markers
filters.onchange = change;
// Initially filter the markers
change();

 markercluster.addLayer(markers);
 map.addLayer(markercluster);