diff --git a/src/geom/quadtree.js b/src/geom/quadtree.js
index b3fe1d081eece..59f4dc8b089bb 100644
--- a/src/geom/quadtree.js
+++ b/src/geom/quadtree.js
@@ -150,7 +150,9 @@ function d3_geom_quadtreeNode() {
   return {
     leaf: true,
     nodes: [],
-    point: null
+    point: null,
+    x: null,
+    y: null
   };
 }