fix(ngClass): remove classes already on the dom

src/ng/directive/ngClass.js

@@ -66,10 +66,26 @@ function classDirective(name, selector) {
           }
         }
 
+        function removeFalseClasses(classVal) {
+          if (isArray(classVal) || isString(classVal)) {
+            return;
+          }
+          if (isObject(classVal)) {
+            var classes = [], i = 0;
+            forEach(classVal, function(v, k) {
+              if (!v) {
+                classes = classes.concat(k.split(' '));
+              }
+            });
+            attr.$removeClass(classes);
+          }
+        }
+
         function ngClassWatchAction(newVal) {
           if (selector === true || scope.$index % 2 === selector) {
             var newClasses = arrayClasses(newVal || []);
             if (!oldVal) {
+              removeFalseClasses(newVal);
               addClasses(newClasses);
             } else if (!equals(newVal,oldVal)) {
               var oldClasses = arrayClasses(oldVal);

test/ng/directive/ngClassSpec.js

@@ -45,22 +45,26 @@ describe('ngClass', function() {
   it('should support adding multiple classes conditionally via a map of class names to boolean ' +
       'expressions', inject(function($rootScope, $compile) {
     element = $compile(
-        '<div class="existing" ' +
-            'ng-class="{A: conditionA, B: conditionB(), AnotB: conditionA&&!conditionB()}">' +
+        '<div class="existing existingTrue existingFalse" ' +
+            'ng-class="{A: conditionA, B: conditionB(), AnotB: conditionA&&!conditionB(), existingTrue: true, existingFalse: false}">' +
         '</div>')($rootScope);
     $rootScope.conditionA = true;
     $rootScope.$digest();
     expect(element.hasClass('existing')).toBeTruthy();
     expect(element.hasClass('A')).toBeTruthy();
     expect(element.hasClass('B')).toBeFalsy();
     expect(element.hasClass('AnotB')).toBeTruthy();
+    expect(element.hasClass('existingTrue')).toBeTruthy();
+    expect(element.hasClass('existingFalse')).toBeFalsy();
 
     $rootScope.conditionB = function() { return true; };
     $rootScope.$digest();
     expect(element.hasClass('existing')).toBeTruthy();
     expect(element.hasClass('A')).toBeTruthy();
     expect(element.hasClass('B')).toBeTruthy();
     expect(element.hasClass('AnotB')).toBeFalsy();
+    expect(element.hasClass('existingTrue')).toBeTruthy();
+    expect(element.hasClass('existingFalse')).toBeFalsy();
   }));