Index: node_modules/d3-chord/src/ribbon.js
===================================================================
--- node_modules/d3-chord/src/ribbon.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-chord/src/ribbon.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,134 @@
+import {path} from "d3-path";
+import {slice} from "./array.js";
+import constant from "./constant.js";
+import {abs, cos, epsilon, halfPi, sin} from "./math.js";
+
+function defaultSource(d) {
+  return d.source;
+}
+
+function defaultTarget(d) {
+  return d.target;
+}
+
+function defaultRadius(d) {
+  return d.radius;
+}
+
+function defaultStartAngle(d) {
+  return d.startAngle;
+}
+
+function defaultEndAngle(d) {
+  return d.endAngle;
+}
+
+function defaultPadAngle() {
+  return 0;
+}
+
+function defaultArrowheadRadius() {
+  return 10;
+}
+
+function ribbon(headRadius) {
+  var source = defaultSource,
+      target = defaultTarget,
+      sourceRadius = defaultRadius,
+      targetRadius = defaultRadius,
+      startAngle = defaultStartAngle,
+      endAngle = defaultEndAngle,
+      padAngle = defaultPadAngle,
+      context = null;
+
+  function ribbon() {
+    var buffer,
+        s = source.apply(this, arguments),
+        t = target.apply(this, arguments),
+        ap = padAngle.apply(this, arguments) / 2,
+        argv = slice.call(arguments),
+        sr = +sourceRadius.apply(this, (argv[0] = s, argv)),
+        sa0 = startAngle.apply(this, argv) - halfPi,
+        sa1 = endAngle.apply(this, argv) - halfPi,
+        tr = +targetRadius.apply(this, (argv[0] = t, argv)),
+        ta0 = startAngle.apply(this, argv) - halfPi,
+        ta1 = endAngle.apply(this, argv) - halfPi;
+
+    if (!context) context = buffer = path();
+
+    if (ap > epsilon) {
+      if (abs(sa1 - sa0) > ap * 2 + epsilon) sa1 > sa0 ? (sa0 += ap, sa1 -= ap) : (sa0 -= ap, sa1 += ap);
+      else sa0 = sa1 = (sa0 + sa1) / 2;
+      if (abs(ta1 - ta0) > ap * 2 + epsilon) ta1 > ta0 ? (ta0 += ap, ta1 -= ap) : (ta0 -= ap, ta1 += ap);
+      else ta0 = ta1 = (ta0 + ta1) / 2;
+    }
+
+    context.moveTo(sr * cos(sa0), sr * sin(sa0));
+    context.arc(0, 0, sr, sa0, sa1);
+    if (sa0 !== ta0 || sa1 !== ta1) {
+      if (headRadius) {
+        var hr = +headRadius.apply(this, arguments), tr2 = tr - hr, ta2 = (ta0 + ta1) / 2;
+        context.quadraticCurveTo(0, 0, tr2 * cos(ta0), tr2 * sin(ta0));
+        context.lineTo(tr * cos(ta2), tr * sin(ta2));
+        context.lineTo(tr2 * cos(ta1), tr2 * sin(ta1));
+      } else {
+        context.quadraticCurveTo(0, 0, tr * cos(ta0), tr * sin(ta0));
+        context.arc(0, 0, tr, ta0, ta1);
+      }
+    }
+    context.quadraticCurveTo(0, 0, sr * cos(sa0), sr * sin(sa0));
+    context.closePath();
+
+    if (buffer) return context = null, buffer + "" || null;
+  }
+
+  if (headRadius) ribbon.headRadius = function(_) {
+    return arguments.length ? (headRadius = typeof _ === "function" ? _ : constant(+_), ribbon) : headRadius;
+  };
+
+  ribbon.radius = function(_) {
+    return arguments.length ? (sourceRadius = targetRadius = typeof _ === "function" ? _ : constant(+_), ribbon) : sourceRadius;
+  };
+
+  ribbon.sourceRadius = function(_) {
+    return arguments.length ? (sourceRadius = typeof _ === "function" ? _ : constant(+_), ribbon) : sourceRadius;
+  };
+
+  ribbon.targetRadius = function(_) {
+    return arguments.length ? (targetRadius = typeof _ === "function" ? _ : constant(+_), ribbon) : targetRadius;
+  };
+
+  ribbon.startAngle = function(_) {
+    return arguments.length ? (startAngle = typeof _ === "function" ? _ : constant(+_), ribbon) : startAngle;
+  };
+
+  ribbon.endAngle = function(_) {
+    return arguments.length ? (endAngle = typeof _ === "function" ? _ : constant(+_), ribbon) : endAngle;
+  };
+
+  ribbon.padAngle = function(_) {
+    return arguments.length ? (padAngle = typeof _ === "function" ? _ : constant(+_), ribbon) : padAngle;
+  };
+
+  ribbon.source = function(_) {
+    return arguments.length ? (source = _, ribbon) : source;
+  };
+
+  ribbon.target = function(_) {
+    return arguments.length ? (target = _, ribbon) : target;
+  };
+
+  ribbon.context = function(_) {
+    return arguments.length ? ((context = _ == null ? null : _), ribbon) : context;
+  };
+
+  return ribbon;
+}
+
+export default function() {
+  return ribbon();
+}
+
+export function ribbonArrow() {
+  return ribbon(defaultArrowheadRadius);
+}