Prevent unnecessary rerendering of not changed clusters

src/markerclusterer.ts

@@ -179,7 +179,8 @@ export class MarkerClusterer extends OverlayViewSafe {
       });
 
       // Allow algorithms to return flag on whether the clusters/markers have changed.
-      if (changed || changed == undefined) {
+      // But if the cluster amount hasnt changed dont rerender unnecessarily, since nothing has changed
+      if (clusters.length !== this.clusters.length && (changed || changed == undefined)) {
         // Accumulate the markers of the clusters composed of a single marker.
         // Those clusters directly use the marker.
         // Clusters with more than one markers use a group marker generated by a renderer.
@@ -207,15 +208,15 @@ export class MarkerClusterer extends OverlayViewSafe {
             // Delay the removal of old group markers to avoid flickering.
             groupMarkers.push(cluster.marker);
           }
-        }
 
-        this.clusters = clusters;
-        this.renderClusters();
+          this.clusters = clusters;
+          this.renderClusters();
 
-        // Delayed removal of the markers of the former groups.
-        requestAnimationFrame(() =>
-          groupMarkers.forEach((marker) => MarkerUtils.setMap(marker, null))
-        );
+          // Delayed removal of the markers of the former groups.
+          requestAnimationFrame(() =>
+            groupMarkers.forEach((marker) => MarkerUtils.setMap(marker, null))
+          );
+        }
       }
       google.maps.event.trigger(
         this,