Index: node_modules/d3-interpolate/src/hsl.js
===================================================================
--- node_modules/d3-interpolate/src/hsl.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-interpolate/src/hsl.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,21 @@
+import {hsl as colorHsl} from "d3-color";
+import color, {hue} from "./color.js";
+
+function hsl(hue) {
+  return function(start, end) {
+    var h = hue((start = colorHsl(start)).h, (end = colorHsl(end)).h),
+        s = color(start.s, end.s),
+        l = color(start.l, end.l),
+        opacity = color(start.opacity, end.opacity);
+    return function(t) {
+      start.h = h(t);
+      start.s = s(t);
+      start.l = l(t);
+      start.opacity = opacity(t);
+      return start + "";
+    };
+  }
+}
+
+export default hsl(hue);
+export var hslLong = hsl(color);