ng:style remembers previous style and properly resets to it

src/directives.js

@@ -254,8 +254,17 @@ angularDirective("ng:hide", function(expression, element){
 
 angularDirective("ng:style", function(expression, element){
   return function(element){
+    var resetStyle = element.css();
     this.$onEval(function(){
-      element.css(this.$eval(expression) || {});
+      var style = this.$eval(expression) || {}, key, mergedStyle = {};
+      for(key in style) {
+        if (typeof resetStyle[key] == 'undefined') resetStyle[key] = null;
+        mergedStyle[key] = style[key];
+      }
+      for(key in resetStyle) {
+        mergedStyle[key] = mergedStyle[key] || resetStyle[key];
+      }
+      element.css(mergedStyle);
     }, element);
   };
 });

src/jqLite.js

@@ -175,8 +175,15 @@ JQLite.prototype = {
       } else {
         return style[name];
       }
-    } else {
+    } else if(name) {
       extend(style, name);
+    } else {
+      var current = {};
+      for (var i=0; i<style.length; i++) {
+        name = style[i];
+        current[name] = style[name];
+      }
+      return current;
     }
   },
 

test/directivesSpec.js

@@ -168,17 +168,30 @@ describe("directives", function(){
     expect(e2.hasClass('even')).toBeTruthy();
   });
 
-  it('should ng:style', function(){
-    var scope = compile('<div ng:style="{color:\'red\'}"></div>');
-    scope.$eval();
-    expect(element.css('color')).toEqual('red');
-  });
+  describe('ng:style', function(){
+    it('should set', function(){
+      var scope = compile('<div ng:style="{color:\'red\'}"></div>');
+      scope.$eval();
+      expect(element.css('color')).toEqual('red');
+    });
 
-  it('should silently ignore undefined ng:style', function() {
-    var scope = compile('<div ng:style="myStyle"></div>');
-    scope.$eval();
-    dump(sortedHtml(element));
-    expect(element.hasClass('ng-exception')).toBeFalsy();
+    it('should silently ignore undefined style', function() {
+      var scope = compile('<div ng:style="myStyle"></div>');
+      scope.$eval();
+      expect(element.hasClass('ng-exception')).toBeFalsy();
+    });
+
+    it('should preserve and remove previus style', function(){
+      var scope = compile('<div style="color:red;" ng:style="myStyle"></div>');
+      scope.$eval();
+      expect(element.css()).toEqual({color:'red'});
+      scope.myStyle = {color:'blue', width:'10px'};
+      scope.$eval();
+      expect(element.css()).toEqual({color:'blue', width:'10px'});
+      scope.myStyle = {};
+      scope.$eval();
+      expect(element.css()).toEqual({color:'red'});
+    });
   });
 
   it('should ng:show', function(){