Multi-value map support for on.

d3.v2.js

@@ -1705,21 +1705,34 @@
     };
   }
   d3_selectionPrototype.on = function(type, listener, capture) {
-    if (arguments.length < 3) capture = false;
+    var n = arguments.length;
+    if (n < 3) {
+      if (typeof type !== "string") {
+        if (n < 2) listener = false;
+        for (capture in type) this.each(d3_selection_on(capture, type[capture], listener));
+        return this;
+      }
+      if (n < 2) return (n = this.node()["__on" + type]) && n._;
+      capture = false;
+    }
+    return this.each(d3_selection_on(type, listener, capture));
+  };
+  function d3_selection_on(type, listener, capture) {
     var name = "__on" + type, i = type.indexOf(".");
     if (i > 0) type = type.substring(0, i);
-    if (arguments.length < 2) return (i = this.node()[name]) && i._;
-    return this.each(function() {
-      var node = this, args = arguments, o = node[name];
-      if (o) {
-        node.removeEventListener(type, o, o.$);
-        delete node[name];
-      }
-      if (listener) {
-        node.addEventListener(type, node[name] = l, l.$ = capture);
-        l._ = listener;
-      }
-      function l(e) {
+    function onRemove() {
+      var wrapper = this[name];
+      if (wrapper) {
+        this.removeEventListener(type, wrapper, wrapper.$);
+        delete this[name];
+      }
+    }
+    function onAdd() {
+      var node = this, args = arguments;
+      onRemove.call(this);
+      this.addEventListener(type, this[name] = wrapper, wrapper.$ = capture);
+      wrapper._ = listener;
+      function wrapper(e) {
         var o = d3.event;
         d3.event = e;
         args[0] = node.__data__;
@@ -1729,8 +1742,9 @@
           d3.event = o;
         }
       }
-    });
-  };
+    }
+    return listener ? onAdd : onRemove;
+  }
   d3_selectionPrototype.each = function(callback) {
     return d3_selection_each(this, function(node, i, j) {
       callback.call(node, node.__data__, i, j);

src/core/selection-attr.js

@@ -12,7 +12,7 @@ d3_selectionPrototype.attr = function(name, value) {
 
     // For attr(object), the object specifies the names and values of the
     // attributes to set or remove. The values may be functions that are
-    // evaluated for each element, or nulls, or strings.
+    // evaluated for each element.
     for (value in name) this.each(d3_selection_attr(value, name[value]));
     return this;
   }

src/core/selection-on.js

@@ -1,35 +1,48 @@
-// type can be namespaced, e.g., "click.foo"
-// listener can be null for removal
 d3_selectionPrototype.on = function(type, listener, capture) {
-  if (arguments.length < 3) capture = false;
+  var n = arguments.length;
+  if (n < 3) {
 
-  // parse the type specifier
+    // For on(object) or on(object, boolean), the object specifies the event
+    // types and listeners to add or remove. The optional boolean specifies
+    // whether the listener captures events.
+    if (typeof type !== "string") {
+      if (n < 2) listener = false;
+      for (capture in type) this.each(d3_selection_on(capture, type[capture], listener));
+      return this;
+    }
+
+    // For on(string), return the listener for the first node.
+    if (n < 2) return (n = this.node()["__on" + type]) && n._;
+
+    // For on(string, function), use the default capture.
+    capture = false;
+  }
+
+  // Otherwise, a type, listener and capture are specified, and handled as below.
+  return this.each(d3_selection_on(type, listener, capture));
+};
+
+function d3_selection_on(type, listener, capture) {
   var name = "__on" + type, i = type.indexOf(".");
   if (i > 0) type = type.substring(0, i);
 
-  // if called with only one argument, return the current listener
-  if (arguments.length < 2) return (i = this.node()[name]) && i._;
+  function onRemove() {
+    var wrapper = this[name];
+    if (wrapper) {
+      this.removeEventListener(type, wrapper, wrapper.$);
+      delete this[name];
+    }
+  }
 
-  // remove the old event listener, and add the new event listener
-  return this.each(function() {
+  function onAdd() {
     var node = this,
-        args = arguments,
-        o = node[name];
-
-    // remove the old listener, if any (using the previously-set capture)
-    if (o) {
-      node.removeEventListener(type, o, o.$);
-      delete node[name];
-    }
+        args = arguments;
 
-    // add the new listener, if any (remembering the capture flag)
-    if (listener) {
-      node.addEventListener(type, node[name] = l, l.$ = capture);
-      l._ = listener; // stash the unwrapped listener for get
-    }
+    onRemove.call(this);
+    this.addEventListener(type, this[name] = wrapper, wrapper.$ = capture);
+    wrapper._ = listener;
 
-    // wrapped event listener that propagates data changes
-    function l(e) {
+    function wrapper(e) {
       var o = d3.event; // Events can be reentrant (e.g., focus).
       d3.event = e;
       args[0] = node.__data__;
@@ -39,5 +52,7 @@ d3_selectionPrototype.on = function(type, listener, capture) {
         d3.event = o;
       }
     }
-  });
-};
+  }
+
+  return listener ? onAdd : onRemove;
+}

src/core/selection-style.js

@@ -4,7 +4,8 @@ d3_selectionPrototype.style = function(name, value, priority) {
 
     // For style(object) or style(object, string), the object specifies the
     // names and values of the attributes to set or remove. The values may be
-    // functions that are evaluated for each element.
+    // functions that are evaluated for each element. The optional string
+    // specifies the priority.
     if (typeof name !== "string") {
       if (n < 2) value = "";
       for (priority in name) this.each(d3_selection_style(priority, name[priority], value));

test/core/selection-on-test.js

@@ -48,11 +48,21 @@ suite.addBatch({
     "observes the specified namespace": function(body) {
       var form = body.append("form"), foo = 0, bar = 0;
       form.on("submit.foo", function() { ++foo; });
-      form.on("submit.bar", function() { ++bar; });
+      form.on({"submit.bar": function() { ++bar; }});
       form.append("input").attr("type", "submit").node().click();
       assert.equal(foo, 1);
       assert.equal(bar, 1);
     },
+    "can register listeners as a map": function(body) {
+      var form = body.append("form"), count = 0, fail = 0;
+      form.on({submit: function() { ++fail; }});
+      form.on({submit: function() { ++count; }});
+      form.append("input").attr("type", "submit").node().click();
+      assert.equal(count, 1);
+      assert.equal(fail, 0);
+      form.on({submit: null});
+      assert.isUndefined(form.on("submit"));
+    },
     /* Not really sure how to test this one…
     "observes the specified capture flag": function(body) {
     },