fix: advanced marker position can be null

src/algorithms/grid.ts

@@ -115,12 +115,18 @@ export class GridAlgorithm extends AbstractViewportAlgorithm {
   ): void {
     let maxDistance = this.maxDistance; // Some large number
     let cluster: Cluster = null;
+    const position = MarkerUtils.getPosition(marker);
+
+    if (position === null) {
+      // Marker has no position, which makes it invisible and not part of the cluster
+      return;
+    }
 
     for (let i = 0; i < this.clusters.length; i++) {
       const candidate = this.clusters[i];
       const distance = distanceBetweenPoints(
         candidate.bounds.getCenter().toJSON(),
-        MarkerUtils.getPosition(marker).toJSON()
+        position.toJSON()
       );
 
       if (distance < maxDistance) {
@@ -135,7 +141,7 @@ export class GridAlgorithm extends AbstractViewportAlgorithm {
         cluster.bounds,
         projection,
         this.gridSize
-      ).contains(MarkerUtils.getPosition(marker))
+      ).contains(position)
     ) {
       cluster.push(marker);
     } else {

src/algorithms/supercluster.ts

@@ -59,6 +59,10 @@ export class SuperClusterAlgorithm extends AbstractAlgorithm {
 
       const points = this.markers.map((marker) => {
         const position = MarkerUtils.getPosition(marker);
+        if (!position) {
+          return null;
+        }
+
         const coordinates = [position.lng(), position.lat()];
         return {
           type: "Feature" as const,
@@ -69,7 +73,7 @@ export class SuperClusterAlgorithm extends AbstractAlgorithm {
           properties: { marker },
         };
       });
-      this.superCluster.load(points);
+      this.superCluster.load(points.filter((p) => p != null));
     }
 
     if (!changed) {

src/algorithms/superviewport.ts

@@ -85,6 +85,10 @@ export class SuperClusterViewportAlgorithm extends AbstractViewportAlgorithm {
 
       const points = this.markers.map((marker) => {
         const position = MarkerUtils.getPosition(marker);
+        if (!position) {
+          return null;
+        }
+
         const coordinates = [position.lng(), position.lat()];
         return {
           type: "Feature" as const,
@@ -95,7 +99,7 @@ export class SuperClusterViewportAlgorithm extends AbstractViewportAlgorithm {
           properties: { marker },
         };
       });
-      this.superCluster.load(points);
+      this.superCluster.load(points.filter((p) => p != null));
     }
 
     if (changed) {

src/algorithms/utils.ts

@@ -36,9 +36,10 @@ export const filterMarkersToPaddedViewport = (
     mapCanvasProjection,
     viewportPaddingPixels
   );
-  return markers.filter((marker) =>
-    extendedMapBounds.contains(MarkerUtils.getPosition(marker))
-  );
+  return markers.filter((marker) => {
+    const position = MarkerUtils.getPosition(marker);
+    return position ? extendedMapBounds.contains(position) : false;
+  });
 };
 
 /**

src/cluster.ts

@@ -45,7 +45,10 @@ export class Cluster {
 
     const bounds = new google.maps.LatLngBounds(this._position, this._position);
     for (const marker of this.markers) {
-      bounds.extend(MarkerUtils.getPosition(marker));
+      const position = MarkerUtils.getPosition(marker);
+      if (position) {
+        bounds.extend(position);
+      }
     }
     return bounds;
   }

src/marker-utils.ts

@@ -50,7 +50,7 @@ export class MarkerUtils {
     }
   }
 
-  public static getPosition(marker: Marker): google.maps.LatLng {
+  public static getPosition(marker: Marker): google.maps.LatLng | null {
     // SuperClusterAlgorithm.calculate expects a LatLng instance so we fake it for Adv Markers
     if (this.isAdvancedMarker(marker)) {
       if (marker.position) {
@@ -65,21 +65,22 @@ export class MarkerUtils {
           );
         }
       }
-      return new google.maps.LatLng(null);
+      return null;
     }
     return marker.getPosition();
   }
 
   public static getVisible(marker: Marker) {
     if (this.isAdvancedMarker(marker)) {
       /**
-       * Always return true for Advanced Markers because the clusterer
-       * uses getVisible as a way to count legacy markers not as an actual
-       * indicator of visibility for some reason. Even when markers are hidden
-       * Marker.getVisible returns `true` and this is used to set the marker count
-       * on the cluster. See the behavior of Cluster.count
+       * As per google.maps.marker.AdvancedMarkerElement documentation:
+       * An AdvancedMarkerElement may be constructed without a position,
+       * but will not be displayed until its position is provided.
+       *
+       * The same goes for the map property. But in case of clustering this
+       * is always set to null as we don't want to show the marker on the map.
        */
-      return true;
+      return marker.position !== null;
     }
     return marker.getVisible();
   }