Index: node_modules/d3-transition/src/transition/easeVarying.js
===================================================================
--- node_modules/d3-transition/src/transition/easeVarying.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-transition/src/transition/easeVarying.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,14 @@
+import {set} from "./schedule.js";
+
+function easeVarying(id, value) {
+  return function() {
+    var v = value.apply(this, arguments);
+    if (typeof v !== "function") throw new Error;
+    set(this, id).ease = v;
+  };
+}
+
+export default function(value) {
+  if (typeof value !== "function") throw new Error;
+  return this.each(easeVarying(this._id, value));
+}