Index: node_modules/d3-array/src/reduce.js
===================================================================
--- node_modules/d3-array/src/reduce.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-array/src/reduce.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,14 @@
+export default function reduce(values, reducer, value) {
+  if (typeof reducer !== "function") throw new TypeError("reducer is not a function");
+  const iterator = values[Symbol.iterator]();
+  let done, next, index = -1;
+  if (arguments.length < 3) {
+    ({done, value} = iterator.next());
+    if (done) return;
+    ++index;
+  }
+  while (({done, value: next} = iterator.next()), !done) {
+    value = reducer(value, next, ++index, values);
+  }
+  return value;
+}