Source: bemap-leaflet/bemap-map-leaflet-polygon.js

/**
 * Add a bemap.Polygon to the layer
 * @public
 * @param {bemap.Polygon} bemap.Polygon.
 * @param {object} options
 * @return {bemap.LeafletMap}
 */
bemap.LeafletMap.prototype.addPolygon = function(polygon, options) {
  if (polygon && bemap.inheritsof(polygon, bemap.Polygon)) {

    var style = polygon.getStyle();
    var fillColor = style.getFillColor();
    var borderColor = style.getBorderColor();

    polygon.native = L.polygon([polygon.getLatLonArrays()], {
      fillColor: fillColor.getHex(),
      opacity: fillColor.getAlpha(),
      color: borderColor.getHex(),
      weight: style.getBorderWidth(),
    });

    if (polygon.map === null) {
      polygon.map = this;
    }

    var opts = options || {};
    var l = null;

    if (opts.layer !== undefined && (bemap.inheritsof(opts.layer, bemap.VectorLayer))) {
      l = opts.layer;
    } else {
      l = this.getLayerByName(bemap.Map.DEFAULT_LAYER.POLYGON);
      if (l === null) {
        l = new bemap.VectorLayer({
          name: bemap.Map.DEFAULT_LAYER.POLYGON
        });
        this.addLayer(l);
      }
    }

    if (polygon.layer === null) {
      polygon.layer = l;
    }

    polygon.native.addTo(l.native);
  }
  return this;
};

/**
 * Remove a polygon from his layer.
 * @public
 * @param {bemap.Polygon} polygon the polygon object to remove.
 */
bemap.LeafletMap.prototype.removePolygon = function(polygon) {
  if (polygon && polygon.layer && polygon.layer.native && bemap.inheritsof(polygon, bemap.Polygon)) {
    polygon.map.native.removeLayer(polygon.native);
    polygon.layer = null;
    polygon.map = null;
  }
  return this;
};

/**
 * Set the listner when an specified eventType occur on bemap.Polygon.
 * @public
 * @param {bemap.Polygon} polygon
 * @param {bemap.Map.EventType} eventType Event type.
 * @param {function} callback Function will be called when the specified eventType is occur.
 * @param {object} options options.
 * @return {bemap.Listener} this.
 */
bemap.LeafletMap.prototype.onPolygon = function(polygon, eventType, callback, options) {

  var opts = options ? options : {};

  var nativeListener = polygon.native.on(eventType, function(evt) {
    var mapEvent = new bemap.MapEvent({
      native: evt,
      bemapObject: polygon,
      x: evt.containerPoint ? evt.containerPoint.x : undefined,
      y: evt.containerPoint ? evt.containerPoint.y : undefined,
      coordinate: evt.latlng ? new bemap.Coordinate(evt.latlng.lng, evt.latlng.lat) : undefined,
      properties: options,
      map: this
    });
    callback(mapEvent);
  });
  var listener = new bemap.Listener({
    native: nativeListener,
    callback: callback,
    key: eventType,
    bemapObject: polygon
  });

  return listener;
};

/**
 * Define the draggable capability for bemap.Polygon.
 * @protected
 * @param {bemap.Polygon} polygon bemap object.
 * @param {function} callback Function will be called when the specified eventType is occur.
 * @param {object} options Options.
 * @param {bemap.Layer} options.layerFilter set the bemap layer used as filter.
 * @return {bemap.Listener} bemap.listener.
 */
/*bemap.LeafletMap.prototype.draggablePolygon = function(polygon, callback, options) {
  var _this = this,
    opts = options ? options : {},
    startPixel, startCoordinate;

  polygon.native.on('mousedown', function(evt) {
    _this.native.dragging.disable();
    startPixel = evt.containerPoint;

    var latlng = polygon.native._latlng;
    var polygonStartingLat = latlng.lat;
    var polygonStartingLng = latlng.lng;

    startCoordinate = new bemap.Coordinate(polygonStartingLat, polygonStartingLng);

    latlng = evt.latlng;
    var mouseStartingLat = latlng.lat;
    var mouseStartingLng = latlng.lng;

    _this.native.on('mousemove', function(evt) {
      latlng = evt.latlng;
      var mouseNewLat = latlng.lat;
      var mouseNewLng = latlng.lng;

      var latDifference = mouseStartingLat - mouseNewLat;
      var lngDifference = mouseStartingLng - mouseNewLng;
      var center = [polygonStartingLat - latDifference, polygonStartingLng - lngDifference];
      polygon.native.setLatLng(center);
    });
  });

  this.native.on('mouseup', function(evt) {
    _this.native.dragging.enable();
    _this.native.removeEventListener('mousemove');

    var mapEvent = new bemap.MapEvent({
      native: evt,
      bemapObject: polygon,
      x: evt.containerPoint ? evt.containerPoint.x : undefined,
      y: evt.containerPoint ? evt.containerPoint.y : undefined,
      coordinate: evt.latlng ? new bemap.Coordinate(evt.latlng.lat, evt.latlng.lng) : undefined,
      //startX: startPixel.x,
      //startY: startPixel.y,
      //startCoordinate: startCoordinate,
      properties: options,
      map: this
    });

    callback(mapEvent);
  });

  this.events.dragFeature = new bemap.Listener({
    native: null,
    key: "dragFeature",
    bemapObject: polygon
  });

  return this.events.dragFeature;
};*/