Feature: get zoom level where a point gets unclustered

README.md

@@ -65,6 +65,10 @@ and `offset` is the amount of points to skip (for pagination).
 
 Returns the zoom on which the cluster expands into several children (useful for "click to zoom" feature) given the cluster's `cluster_id`.
 
+#### `getPointUnclusterZoom(point)`
+
+Returns the zoom on which a point appears unclustered. The point must be provided as array with `[Lng, Lat]`.
+
 ## Options
 
 | Option     | Default | Description                                                       |

index.js

@@ -191,6 +191,28 @@ export default class Supercluster {
         return expansionZoom;
     }
 
+    getPointUnclusterZoom(point) {
+        const [lng, lat] = point;
+        const pointX = fround(lngX(lng));
+        const pointY = fround(latY(lat));
+
+        let expansionZoom = this.options.minZoom;
+        while (expansionZoom < this.options.maxZoom) {
+            const tree = this.trees[expansionZoom];
+
+            const pointIdxs = tree.within(pointX, pointY, 0);
+
+            const unclustered = pointIdxs.some(
+                idx => tree.data[idx].parentId !== -1
+            );
+            if (unclustered) return expansionZoom;
+
+            expansionZoom++;
+        }
+
+        return expansionZoom;
+    }
+
     _appendLeaves(result, clusterId, limit, offset, skipped) {
         const children = this.getChildren(clusterId);
 

test/test.js

@@ -172,3 +172,17 @@ test('makes sure unclustered point coords are not rounded', () => {
 
     assert.deepEqual(index.getTile(20, 1028744, 656754).features[0].geometry[0], [421, 281]);
 });
+
+test('returns point uncluster zoom level', () => {
+    const points = [
+        {type: 'Feature', geometry: {type: 'Point', coordinates: [173, 53]}},
+        {type: 'Feature', geometry: {type: 'Point', coordinates: [174, 54]}}
+    ];
+    const index = new Supercluster({maxZoom: 19}).load(points);
+    const cluster = index.getClusters([172, 52, 175, 55], 1)[0];
+
+    const clusterExpansionZoom = index.getClusterExpansionZoom(cluster.id);
+    const pointUnclusterZoom = index.getPointUnclusterZoom(points[0].geometry.coordinates);
+
+    assert.deepEqual(clusterExpansionZoom, pointUnclusterZoom);
+});