Include points that lie on the getClusters bbox edge

index.js

@@ -159,7 +159,13 @@ export default class Supercluster {
         }
 
         const tree = this.trees[this._limitZoom(zoom)];
-        const ids = tree.range(encode(lngX(minLng)), encode(latY(maxLat)), encode(lngX(maxLng)), encode(latY(minLat)));
+        // Stored coords are Int32 truncations of encode(). Truncate the query the same way
+        // so a point that lies on the bbox edge is not pushed just outside.
+        const ids = tree.range(
+            Math.trunc(encode(lngX(minLng))),
+            Math.trunc(encode(latY(maxLat))),
+            Math.trunc(encode(lngX(maxLng))),
+            Math.trunc(encode(latY(minLat))));
         const data = tree.data;
         const clusters = [];
         for (const id of ids) clusters.push(this._featureJSON(data, this.stride * id));

test/test.js

@@ -253,3 +253,17 @@ test('does not throw on zero items', () => {
         assert.deepEqual(index.getClusters([-180, -85, 180, 85], 0), []);
     });
 });
+
+test('includes a point that lies on the bbox edge', () => {
+    const sw = [-123.245515, 43.9150233333333];
+    const ne = [-123.192528333333, 44.0307166666667];
+    const features = [
+        {type: 'Feature', properties: {id: 'sw'}, geometry: {type: 'Point', coordinates: sw}},
+        {type: 'Feature', properties: {id: 'ne'}, geometry: {type: 'Point', coordinates: ne}},
+        {type: 'Feature', properties: {id: 'in'}, geometry: {type: 'Point', coordinates: [-123.211605, 43.972615]}},
+        {type: 'Feature', properties: {id: 'out'}, geometry: {type: 'Point', coordinates: [-124, 43]}}
+    ];
+    const index = new Supercluster({radius: 0}).load(features);
+    const ids = index.getClusters([sw[0], sw[1], ne[0], ne[1]], 16).map(f => f.properties.id).sort();
+    assert.deepEqual(ids, ['in', 'ne', 'sw']);
+});