Fix a bug in enter selection's empty.

Due to the ordering in which the prototypes are defined, it was still undefined!
Also, the empty method depends on the node method being defined. Added a test.

Makefile

@@ -94,8 +94,6 @@ d3.core.js: \
 	src/core/selection-insert.js \
 	src/core/selection-remove.js \
 	src/core/selection-data.js \
-	src/core/selection-enter.js \
-	src/core/selection-enter-select.js \
 	src/core/selection-filter.js \
 	src/core/selection-map.js \
 	src/core/selection-sort.js \
@@ -106,6 +104,8 @@ d3.core.js: \
 	src/core/selection-node.js \
 	src/core/selection-transition.js \
 	src/core/selection-root.js \
+	src/core/selection-enter.js \
+	src/core/selection-enter-select.js \
 	src/core/transition.js \
 	src/core/transition-select.js \
 	src/core/transition-selectAll.js \

d3.js

@@ -10,7 +10,7 @@ try {
     d3_style_setProperty.call(this, name, value + "", priority);
   };
 }
-d3 = {version: "2.4.4"}; // semver
+d3 = {version: "2.4.5"}; // semver
 var d3_array = d3_arraySlice; // conversion for NodeLists
 
 function d3_arrayCopy(pseudoarray) {
@@ -1666,40 +1666,6 @@ d3_selectionPrototype.data = function(data, join) {
 function d3_selection_dataNode(data) {
   return {__data__: data};
 }
-function d3_selection_enter(selection) {
-  d3_arraySubclass(selection, d3_selection_enterPrototype);
-  return selection;
-}
-
-var d3_selection_enterPrototype = [];
-
-d3_selection_enterPrototype.append = d3_selectionPrototype.append;
-d3_selection_enterPrototype.insert = d3_selectionPrototype.insert;
-d3_selection_enterPrototype.empty = d3_selectionPrototype.empty;
-d3_selection_enterPrototype.select = function(selector) {
-  var subgroups = [],
-      subgroup,
-      subnode,
-      upgroup,
-      group,
-      node;
-
-  for (var j = -1, m = this.length; ++j < m;) {
-    upgroup = (group = this[j]).update;
-    subgroups.push(subgroup = []);
-    subgroup.parentNode = group.parentNode;
-    for (var i = -1, n = group.length; ++i < n;) {
-      if (node = group[i]) {
-        subgroup.push(upgroup[i] = subnode = selector.call(group.parentNode, node.__data__, i));
-        subnode.__data__ = node.__data__;
-      } else {
-        subgroup.push(null);
-      }
-    }
-  }
-
-  return d3_selection(subgroups);
-};
 // TODO preserve null elements to maintain index?
 d3_selectionPrototype.filter = function(filter) {
   var subgroups = [],
@@ -1844,6 +1810,41 @@ d3.selectAll = function(selector) {
       ? d3_selectionRoot.selectAll(selector)
       : d3_selection([d3_array(selector)]); // assume node[]
 };
+function d3_selection_enter(selection) {
+  d3_arraySubclass(selection, d3_selection_enterPrototype);
+  return selection;
+}
+
+var d3_selection_enterPrototype = [];
+
+d3_selection_enterPrototype.append = d3_selectionPrototype.append;
+d3_selection_enterPrototype.insert = d3_selectionPrototype.insert;
+d3_selection_enterPrototype.empty = d3_selectionPrototype.empty;
+d3_selection_enterPrototype.node = d3_selectionPrototype.node;
+d3_selection_enterPrototype.select = function(selector) {
+  var subgroups = [],
+      subgroup,
+      subnode,
+      upgroup,
+      group,
+      node;
+
+  for (var j = -1, m = this.length; ++j < m;) {
+    upgroup = (group = this[j]).update;
+    subgroups.push(subgroup = []);
+    subgroup.parentNode = group.parentNode;
+    for (var i = -1, n = group.length; ++i < n;) {
+      if (node = group[i]) {
+        subgroup.push(upgroup[i] = subnode = selector.call(group.parentNode, node.__data__, i));
+        subnode.__data__ = node.__data__;
+      } else {
+        subgroup.push(null);
+      }
+    }
+  }
+
+  return d3_selection(subgroups);
+};
 function d3_transition(groups, id, time) {
   d3_arraySubclass(groups, d3_transitionPrototype);
 

package.json

 {
   "name": "d3",
-  "version": "2.4.4",
+  "version": "2.4.5",
   "description": "A small, free JavaScript library for manipulating documents based on data.",
   "keywords": [
     "dom",

src/core/core.js

-d3 = {version: "2.4.4"}; // semver
+d3 = {version: "2.4.5"}; // semver

src/core/selection-enter.js

@@ -8,3 +8,4 @@ var d3_selection_enterPrototype = [];
 d3_selection_enterPrototype.append = d3_selectionPrototype.append;
 d3_selection_enterPrototype.insert = d3_selectionPrototype.insert;
 d3_selection_enterPrototype.empty = d3_selectionPrototype.empty;
+d3_selection_enterPrototype.node = d3_selectionPrototype.node;

test/core/selection-data-test.js

@@ -109,6 +109,7 @@ suite.addBatch({
     },
     "defines an enter selection for entering data": function(span) {
       var enter = span.data(d3.range(4)).enter();
+      assert.isFalse(enter.empty());
       assert.equal(enter.length, 2);
       assert.equal(enter[0].length, 4);
       assert.equal(enter[1].length, 4);
@@ -123,6 +124,7 @@ suite.addBatch({
     },
     "defines an exit selection for exiting data": function(span) {
       var exit = span.data(d3.range(1)).exit();
+      assert.isFalse(exit.empty());
       assert.equal(exit.length, 2);
       assert.equal(exit[0].length, 2);
       assert.equal(exit[1].length, 2);
@@ -133,6 +135,7 @@ suite.addBatch({
     },
     "observes the specified key function": function(span) {
       var update = span.data([1, 2], Number);
+      assert.isFalse(update.empty());
       assert.equal(update.length, 2);
       assert.equal(update[0].length, 2);
       assert.equal(update[1].length, 2);