Clustering GeoJson Points about ui-leaflet HOT 8 OPEN

        L.GeoJSON = L.GeoJSON.extend({
            addTo: function(map) {
                var self = this;
                map.addLayer(this.markers);
                var parentRemove = L.GeoJSON.prototype.onRemove;
                L.GeoJSON.prototype.onRemove = function (map) {
                    self.markers.removeLayer(self);
                    delete self.markers;
                    parentRemove(map);
                };
                return this;
            }
        });
        L.geoJson = function (geojson, options) {
            var geoJSON = new L.GeoJSON(geojson, options);
            var markers = new L.MarkerClusterGroup({
                spiderfyOnMaxZoom: false,
                showCoverageOnHover: true,
                zoomToBoundsOnClick: true,
                disableClusteringAtZoom: 18
            });
            markers.setGeoJSON = function(data) {
                geoJSON.setGeoJSON(data);
            };
            markers.addLayer(geoJSON);
            geoJSON.markers = markers;
            return  markers;
        };