Index: node_modules/d3-selection/src/selection/on.js
===================================================================
--- node_modules/d3-selection/src/selection/on.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-selection/src/selection/on.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,67 @@
+function contextListener(listener) {
+  return function(event) {
+    listener.call(this, event, this.__data__);
+  };
+}
+
+function parseTypenames(typenames) {
+  return typenames.trim().split(/^|\s+/).map(function(t) {
+    var name = "", i = t.indexOf(".");
+    if (i >= 0) name = t.slice(i + 1), t = t.slice(0, i);
+    return {type: t, name: name};
+  });
+}
+
+function onRemove(typename) {
+  return function() {
+    var on = this.__on;
+    if (!on) return;
+    for (var j = 0, i = -1, m = on.length, o; j < m; ++j) {
+      if (o = on[j], (!typename.type || o.type === typename.type) && o.name === typename.name) {
+        this.removeEventListener(o.type, o.listener, o.options);
+      } else {
+        on[++i] = o;
+      }
+    }
+    if (++i) on.length = i;
+    else delete this.__on;
+  };
+}
+
+function onAdd(typename, value, options) {
+  return function() {
+    var on = this.__on, o, listener = contextListener(value);
+    if (on) for (var j = 0, m = on.length; j < m; ++j) {
+      if ((o = on[j]).type === typename.type && o.name === typename.name) {
+        this.removeEventListener(o.type, o.listener, o.options);
+        this.addEventListener(o.type, o.listener = listener, o.options = options);
+        o.value = value;
+        return;
+      }
+    }
+    this.addEventListener(typename.type, listener, options);
+    o = {type: typename.type, name: typename.name, value: value, listener: listener, options: options};
+    if (!on) this.__on = [o];
+    else on.push(o);
+  };
+}
+
+export default function(typename, value, options) {
+  var typenames = parseTypenames(typename + ""), i, n = typenames.length, t;
+
+  if (arguments.length < 2) {
+    var on = this.node().__on;
+    if (on) for (var j = 0, m = on.length, o; j < m; ++j) {
+      for (i = 0, o = on[j]; i < n; ++i) {
+        if ((t = typenames[i]).type === o.type && t.name === o.name) {
+          return o.value;
+        }
+      }
+    }
+    return;
+  }
+
+  on = value ? onAdd : onRemove;
+  for (i = 0; i < n; ++i) this.each(on(typenames[i], value, options));
+  return this;
+}