fix(jqLite): addClass should ignore falsy values

Author: IgorMinar

src/jqLite.js

@@ -162,8 +162,8 @@ function JQLiteRemoveClass(element, selector) {
   );
 }
 
-function JQLiteAddClass(element, selector ) {
-  if (!JQLiteHasClass(element, selector)) {
+function JQLiteAddClass(element, selector) {
+  if (selector && !JQLiteHasClass(element, selector)) {
     element.className = trim(element.className + ' ' + selector);
   }
 }

test/jqLiteSpec.js

@@ -197,6 +197,20 @@ describe('jqLite', function(){
         expect(jqLite(a).hasClass('abc')).toEqual(true);
         expect(jqLite(b).hasClass('abc')).toEqual(true);
       });
+
+      it('should ignore falsy values', function() {
+        var jqA = jqLite(a);
+        expect(jqA[0].className).toBe('');
+
+        jqA.addClass(undefined);
+        expect(jqA[0].className).toBe('');
+
+        jqA.addClass(null);
+        expect(jqA[0].className).toBe('');
+
+        jqA.addClass(false);
+        expect(jqA[0].className).toBe('');
+      });
     });