code: function (layer, targetCenter, targetZoom) {
                          map._stop();
  
                          var startZoom = map._zoom;
  
                          targetCenter = L.latLng(targetCenter);
                          targetZoom = targetZoom === undefined ? startZoom : targetZoom;
                          targetZoom = Math.min(targetZoom, map.getMaxZoom()); // don't go past max zoom
  
                          var start = Date.now(),
                              duration = 75;
  
                          function frame() {
                              var t = (Date.now() - start) / duration;
  
                              if (t <= 1) {
                                  // reuse internal flyTo frame to ensure these animations are canceled like others
                                  map._flyToFrame = L.Util.requestAnimFrame(frame, map);
                                  setZoomAroundNoMoveEnd(layer, targetCenter, startZoom + (targetZoom - startZoom) * t);
                              } else {
                                  setZoomAroundNoMoveEnd(layer, targetCenter, targetZoom)
                                      ._moveEnd(true);
                              }
                          }
  
                          map._moveStart(true);
  
                          frame.call(map);
                          return map;
                      }
docs: Simplified version of Leaflet's flyTo, for short animations zooming around a point