Index: node_modules/d3-array/src/maxIndex.js
===================================================================
--- node_modules/d3-array/src/maxIndex.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-array/src/maxIndex.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,22 @@
+export default function maxIndex(values, valueof) {
+  let max;
+  let maxIndex = -1;
+  let index = -1;
+  if (valueof === undefined) {
+    for (const value of values) {
+      ++index;
+      if (value != null
+          && (max < value || (max === undefined && value >= value))) {
+        max = value, maxIndex = index;
+      }
+    }
+  } else {
+    for (let value of values) {
+      if ((value = valueof(value, ++index, values)) != null
+          && (max < value || (max === undefined && value >= value))) {
+        max = value, maxIndex = index;
+      }
+    }
+  }
+  return maxIndex;
+}