Index: node_modules/d3-shape/src/curve/basisClosed.js
===================================================================
--- node_modules/d3-shape/src/curve/basisClosed.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-shape/src/curve/basisClosed.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,52 @@
+import noop from "../noop.js";
+import {point} from "./basis.js";
+
+function BasisClosed(context) {
+  this._context = context;
+}
+
+BasisClosed.prototype = {
+  areaStart: noop,
+  areaEnd: noop,
+  lineStart: function() {
+    this._x0 = this._x1 = this._x2 = this._x3 = this._x4 =
+    this._y0 = this._y1 = this._y2 = this._y3 = this._y4 = NaN;
+    this._point = 0;
+  },
+  lineEnd: function() {
+    switch (this._point) {
+      case 1: {
+        this._context.moveTo(this._x2, this._y2);
+        this._context.closePath();
+        break;
+      }
+      case 2: {
+        this._context.moveTo((this._x2 + 2 * this._x3) / 3, (this._y2 + 2 * this._y3) / 3);
+        this._context.lineTo((this._x3 + 2 * this._x2) / 3, (this._y3 + 2 * this._y2) / 3);
+        this._context.closePath();
+        break;
+      }
+      case 3: {
+        this.point(this._x2, this._y2);
+        this.point(this._x3, this._y3);
+        this.point(this._x4, this._y4);
+        break;
+      }
+    }
+  },
+  point: function(x, y) {
+    x = +x, y = +y;
+    switch (this._point) {
+      case 0: this._point = 1; this._x2 = x, this._y2 = y; break;
+      case 1: this._point = 2; this._x3 = x, this._y3 = y; break;
+      case 2: this._point = 3; this._x4 = x, this._y4 = y; this._context.moveTo((this._x0 + 4 * this._x1 + x) / 6, (this._y0 + 4 * this._y1 + y) / 6); break;
+      default: point(this, x, y); break;
+    }
+    this._x0 = this._x1, this._x1 = x;
+    this._y0 = this._y1, this._y1 = y;
+  }
+};
+
+export default function(context) {
+  return new BasisClosed(context);
+}