fix(ngResource): don't filter "$"-prefixed properties from ngResource requests/responses

ngResource no longer filters properties prefixed with a single "$" character from requests or
responses, correcting a regression introduced in 1.2.6 (cb29632a) which caused shallowCopy and
shallowClearAndCopy to ignore properties prefixed with a single "$".

Closes #5666
Closes #6080
Closes #6033

src/Angular.js

@@ -772,7 +772,7 @@ function shallowCopy(src, dst) {
   for(var key in src) {
     // shallowCopy is only ever called by $compile nodeLinkFn, which has control over src
     // so we don't need to worry about using our custom hasOwnProperty here
-    if (src.hasOwnProperty(key) && key.charAt(0) !== '$' && key.charAt(1) !== '$') {
+    if (src.hasOwnProperty(key) && !(key.charAt(0) === '$' && key.charAt(1) === '$')) {
       dst[key] = src[key];
     }
   }

src/ngResource/resource.js

@@ -35,7 +35,7 @@ function shallowClearAndCopy(src, dst) {
   });
 
   for (var key in src) {
-    if (src.hasOwnProperty(key) && key.charAt(0) !== '$' && key.charAt(1) !== '$') {
+    if (src.hasOwnProperty(key) && !(key.charAt(0) === '$' && key.charAt(1) === '$')) {
       dst[key] = src[key];
     }
   }

test/AngularSpec.js

@@ -190,7 +190,7 @@ describe('angular', function() {
       expect(copy.key).toBe(original.key);
     });
 
-    it('should not copy $$ properties nor prototype properties', function() {
+    it('should omit "$$"-prefixed properties', function() {
       var original = {$$some: true, $$: true};
       var clone = {};
 
@@ -198,6 +198,27 @@ describe('angular', function() {
       expect(clone.$$some).toBeUndefined();
       expect(clone.$$).toBeUndefined();
     });
+
+    it('should copy "$"-prefixed properties from copy', function() {
+      var original = {$some: true};
+      var clone = {};
+
+      expect(shallowCopy(original, clone)).toBe(clone);
+      expect(clone.$some).toBe(original.$some);
+    });
+
+    it('should omit properties from prototype chain', function() {
+      var original, clone = {};
+      function Func() {};
+      Func.prototype.hello = "world";
+
+      original = new Func();
+      original.goodbye = "world";
+
+      expect(shallowCopy(original, clone)).toBe(clone);
+      expect(clone.hello).toBeUndefined();
+      expect(clone.goodbye).toBe("world");
+    });
   });
 
   describe('elementHTML', function() {

test/ngResource/resourceSpec.js

@@ -94,6 +94,49 @@ describe("resource", function() {
   });
 
 
+  describe('shallow copy', function() {
+    it('should make a copy', function() {
+      var original = {key:{}};
+      var copy = shallowClearAndCopy(original);
+      expect(copy).toEqual(original);
+      expect(copy.key).toBe(original.key);
+    });
+
+
+    it('should omit "$$"-prefixed properties', function() {
+      var original = {$$some: true, $$: true};
+      var clone = {};
+
+      expect(shallowClearAndCopy(original, clone)).toBe(clone);
+      expect(clone.$$some).toBeUndefined();
+      expect(clone.$$).toBeUndefined();
+    });
+
+
+    it('should copy "$"-prefixed properties from copy', function() {
+      var original = {$some: true};
+      var clone = {};
+
+      expect(shallowClearAndCopy(original, clone)).toBe(clone);
+      expect(clone.$some).toBe(original.$some);
+    });
+
+
+    it('should omit properties from prototype chain', function() {
+      var original, clone = {};
+      function Func() {};
+      Func.prototype.hello = "world";
+
+      original = new Func();
+      original.goodbye = "world";
+
+      expect(shallowClearAndCopy(original, clone)).toBe(clone);
+      expect(clone.hello).toBeUndefined();
+      expect(clone.goodbye).toBe("world");
+    });
+  });
+
+
   it('should default to empty parameters', function() {
     $httpBackend.expect('GET', 'URL').respond({});
     $resource('URL').query();