Index: node_modules/d3-shape/src/curve/catmullRomOpen.js
===================================================================
--- node_modules/d3-shape/src/curve/catmullRomOpen.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-shape/src/curve/catmullRomOpen.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,62 @@
+import {CardinalOpen} from "./cardinalOpen.js";
+import {point} from "./catmullRom.js";
+
+function CatmullRomOpen(context, alpha) {
+  this._context = context;
+  this._alpha = alpha;
+}
+
+CatmullRomOpen.prototype = {
+  areaStart: function() {
+    this._line = 0;
+  },
+  areaEnd: function() {
+    this._line = NaN;
+  },
+  lineStart: function() {
+    this._x0 = this._x1 = this._x2 =
+    this._y0 = this._y1 = this._y2 = NaN;
+    this._l01_a = this._l12_a = this._l23_a =
+    this._l01_2a = this._l12_2a = this._l23_2a =
+    this._point = 0;
+  },
+  lineEnd: function() {
+    if (this._line || (this._line !== 0 && this._point === 3)) this._context.closePath();
+    this._line = 1 - this._line;
+  },
+  point: function(x, y) {
+    x = +x, y = +y;
+
+    if (this._point) {
+      var x23 = this._x2 - x,
+          y23 = this._y2 - y;
+      this._l23_a = Math.sqrt(this._l23_2a = Math.pow(x23 * x23 + y23 * y23, this._alpha));
+    }
+
+    switch (this._point) {
+      case 0: this._point = 1; break;
+      case 1: this._point = 2; break;
+      case 2: this._point = 3; this._line ? this._context.lineTo(this._x2, this._y2) : this._context.moveTo(this._x2, this._y2); break;
+      case 3: this._point = 4; // falls through
+      default: point(this, x, y); break;
+    }
+
+    this._l01_a = this._l12_a, this._l12_a = this._l23_a;
+    this._l01_2a = this._l12_2a, this._l12_2a = this._l23_2a;
+    this._x0 = this._x1, this._x1 = this._x2, this._x2 = x;
+    this._y0 = this._y1, this._y1 = this._y2, this._y2 = y;
+  }
+};
+
+export default (function custom(alpha) {
+
+  function catmullRom(context) {
+    return alpha ? new CatmullRomOpen(context, alpha) : new CardinalOpen(context, 0);
+  }
+
+  catmullRom.alpha = function(alpha) {
+    return custom(+alpha);
+  };
+
+  return catmullRom;
+})(0.5);