Index: node_modules/d3-hierarchy/src/hierarchy/links.js
===================================================================
--- node_modules/d3-hierarchy/src/hierarchy/links.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-hierarchy/src/hierarchy/links.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,9 @@
+export default function() {
+  var root = this, links = [];
+  root.each(function(node) {
+    if (node !== root) { // Don’t include the root’s parent, if any.
+      links.push({source: node.parent, target: node});
+    }
+  });
+  return links;
+}