Index: node_modules/d3-selection/src/selector.js
===================================================================
--- node_modules/d3-selection/src/selector.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-selection/src/selector.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,7 @@
+function none() {}
+
+export default function(selector) {
+  return selector == null ? none : function() {
+    return this.querySelector(selector);
+  };
+}