Double-click on polygons wasn't zooming

inst/htmlwidgets/leaflet.js

@@ -1601,11 +1601,17 @@ methods.addPolygons = function (polygons, layerId, group, options, popup, popupO
     var df = new _dataframe2.default().col("shapes", polygons).col("layerId", layerId).col("group", group).col("popup", popup).col("popupOptions", popupOptions).col("label", label).col("labelOptions", labelOptions).col("highlightOptions", highlightOptions).cbind(options);
 
     addLayers(this, "shape", df, function (df, i) {
-      var shapes = df.get(i, "shapes");
-      shapes = shapes.map(function (polygon) {
+      // This code used to use L.multiPolygon, but that caused
+      // double-click on a multipolygon to fail to zoom in on the
+      // map. Surprisingly, putting all the rings in a single
+      // polygon seems to still work; complicated multipolygons
+      // are still rendered correctly.
+      var shapes = df.get(i, "shapes").map(function (polygon) {
         return polygon.map(_htmlwidgets2.default.dataframeToD3);
-      });
-      return _leaflet2.default.multiPolygon(shapes, df.get(i));
+      }).reduce(function (acc, val) {
+        return acc.concat(val);
+      }, []);
+      return _leaflet2.default.polygon(shapes, df.get(i));
     });
   }
 };
@@ -2290,6 +2296,7 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
 // pixel of the original image has some contribution to the downscaled image)
 // as opposed to a single-step downscaling which will discard a lot of data
 // (and with sparse images at small scales can give very surprising results).
+
 var Mipmapper = function () {
   function Mipmapper(img) {
     _classCallCheck(this, Mipmapper);

javascript/src/methods.js

@@ -535,11 +535,15 @@ methods.addPolygons = function(polygons, layerId, group, options, popup, popupOp
       .cbind(options);
 
     addLayers(this, "shape", df, function(df, i) {
-      let shapes = df.get(i, "shapes");
-      shapes = shapes.map(function(polygon) {
-        return polygon.map(HTMLWidgets.dataframeToD3);
-      });
-      return L.multiPolygon(shapes, df.get(i));
+      // This code used to use L.multiPolygon, but that caused
+      // double-click on a multipolygon to fail to zoom in on the
+      // map. Surprisingly, putting all the rings in a single
+      // polygon seems to still work; complicated multipolygons
+      // are still rendered correctly.
+      let shapes = df.get(i, "shapes")
+        .map(polygon => polygon.map(HTMLWidgets.dataframeToD3))
+        .reduce((acc, val) => acc.concat(val), []);
+      return L.polygon(shapes, df.get(i));
     });
   }
 };