Fix isDict when type is missing in dictionary.

src/util.js

@@ -441,7 +441,14 @@ function isCmd(v, cmd) {
 }
 
 function isDict(v, type) {
-  return v instanceof Dict && (!type || v.get('Type').name == type);
+  if (!(v instanceof Dict)) {
+    return false;
+  }
+  if (!type) {
+    return true;
+  }
+  var dictType = v.get('Type');
+  return isName(dictType) && dictType.name == type;
 }
 
 function isArray(v) {

test/unit/util_spec.js

@@ -63,5 +63,18 @@ describe('util', function() {
     });
   });
 
+  describe('isDict', function() {
+    it('handles empty dictionaries with type check', function() {
+      var dict = new Dict();
+      expect(isDict(dict, 'Page')).toEqual(false);
+    });
+
+    it('handles dictionaries with type check', function() {
+      var dict = new Dict();
+      dict.set('Type', new Name('Page'));
+      expect(isDict(dict, 'Page')).toEqual(true);
+    });
+  });
+
 });