fix: skip clustering for when list of markers is empty (#1014)

Running the supercluster algorithm fails when there are no markers.

Fixes: #991

Author: usefulthink

src/algorithms/supercluster.ts

@@ -68,13 +68,10 @@ export class SuperClusterAlgorithm extends AbstractAlgorithm {
         const position = MarkerUtils.getPosition(marker);
         const coordinates = [position.lng(), position.lat()];
         return {
-          type: "Feature" as const,
-          geometry: {
-            type: "Point" as const,
-            coordinates,
-          },
+          type: "Feature",
+          geometry: { type: "Point", coordinates },
           properties: { marker },
-        };
+        } as const;
       });
       this.superCluster.load(points);
     }
@@ -87,6 +84,13 @@ export class SuperClusterAlgorithm extends AbstractAlgorithm {
 
     this.state = state;
 
+    // when input is empty, return right away
+    if (input.markers.length === 0) {
+      this.clusters = [];
+
+      return { clusters: this.clusters, changed };
+    }
+
     if (changed) {
       this.clusters = this.cluster(input);
     }