feat(tagging compiler): Support comments

Author: jbdeboer

lib/core_dom/tagging_compiler.dart

@@ -68,7 +68,9 @@ class TaggingCompiler implements Compiler {
       } else if (node.nodeType == 3 || node.nodeType == 8) {
         elementBinder = node.nodeType == 3 ? directives.selector.matchText(node) : elementBinder;
 
-        if (elementBinder.hasDirectives && (node.parentNode != null && templateCursor.current.parentNode != null)) {
+        if (elementBinder != null &&
+            elementBinder.hasDirectives &&
+            (node.parentNode != null && templateCursor.current.parentNode != null)) {
           if (directParentElementBinder == null) {
 
             directParentElementBinder = new TaggedElementBinder(null, parentElementBinderOffset);
@@ -84,10 +86,8 @@ class TaggingCompiler implements Compiler {
         } else if(!(node.parentNode != null && templateCursor.current.parentNode != null)) {  // Always add an elementBinder for top-level text.
           elementBinders.add(new TaggedElementBinder(elementBinder, parentElementBinderOffset));
         }
-    //  } else if (node.nodeType == 8) { // comment
-
       } else {
-        throw "wtf";
+        throw "Unsupported node type for $node: [${node.nodeType}]";
       }
     } while (templateCursor.moveNext() && domCursor.moveNext());
 

test/core_dom/compiler_spec.dart

@@ -67,6 +67,18 @@ void main() {
       $compile([], directives);
     }));
 
+    it('should compile a comment with no directives around', inject(() {
+      var element = $('<div><!-- comment --></div>');
+      $compile(element, directives);
+      expect(element.html()).toEqual('<!-- comment -->');
+    }));
+
+    it('should compile a comment when the parent has a directive', inject(() {
+      var element = $('<div ng-show="true"><!-- comment --></div>');
+      $compile(element, directives);
+      expect(element.html()).toEqual('<!-- comment -->');
+    }));
+
     it('should compile a directive in a child', inject(() {
       var element = $('<div><div ng-bind="name"></div></div>');
       var template = $compile(element, directives);