add a test for generateId option

README.md

@@ -75,7 +75,7 @@ Returns the zoom on which the cluster expands into several children (useful for
 | extent     | 512     | (Tiles) Tile extent. Radius is calculated relative to this value. |
 | nodeSize   | 64      | Size of the KD-tree leaf node. Affects performance.               |
 | log        | false   | Whether timing info should be logged.                             |
-| generateId | false   | Whether to generate unique numeric ids for input features.        |
+| generateId | false   | Whether to generate ids for input features in vector tiles.       |
 
 ### Property map/reduce options
 

index.js

@@ -9,7 +9,7 @@ const defaultOptions = {
     nodeSize: 64, // size of the KD-tree leaf node, affects performance
     log: false,   // whether to log timing info
 
-    // whether to generate numeric ids for input features
+    // whether to generate numeric ids for input features (in vector tiles)
     generateId: false,
 
     // a reduce function for calculating custom cluster properties

test/test.js

@@ -37,6 +37,13 @@ test('returns leaves of a cluster', (t) => {
     t.end();
 });
 
+test('generates unique ids with generateId option', (t) => {
+    const index = new Supercluster({generateId: true}).load(places.features);
+    const ids = index.getTile(0, 0, 0).features.filter(f => !f.tags.cluster).map(f => f.id);
+    t.same(ids, [12, 20, 21, 22, 24, 28, 30, 62, 81, 118, 119, 125, 81, 118]);
+    t.end();
+});
+
 test('getLeaves handles null-property features', (t) => {
     const index = new Supercluster().load(places.features.concat([{
         type: 'Feature',