chore(shallowCopy): handle arrays and primitives, and switch to using it where possible

In many cases, we want a shallow copy instead of a full copy

Closes #7618

Author: rodyhaddad

src/Angular.js

@@ -799,20 +799,26 @@ function copy(source, destination) {
 }
 
 /**
- * Create a shallow copy of an object
+ * Creates a shallow copy of an object, an array or a primitive
  */
 function shallowCopy(src, dst) {
-  dst = dst || {};
+  if (isArray(src)) {
+    dst = 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) === '$')) {
-      dst[key] = src[key];
+    for ( var i = 0; i < src.length; i++) {
+      dst[i] = src[i];
+    }
+  } else if (isObject(src)) {
+    dst = dst || {};
+
+    for (var key in src) {
+      if (hasOwnProperty.call(src, key) && !(key.charAt(0) === '$' && key.charAt(1) === '$')) {
+        dst[key] = src[key];
+      }
     }
   }
 
-  return dst;
+  return dst || src;
 }
 
 

src/ng/directive/ngClass.js

@@ -78,7 +78,7 @@ function classDirective(name, selector) {
               updateClasses(oldClasses, newClasses);
             }
           }
-          oldVal = copy(newVal);
+          oldVal = shallowCopy(newVal);
         }
       }
     };

src/ng/directive/select.js

@@ -283,7 +283,7 @@ var selectDirective = ['$compile', '$parse', function($compile,   $parse) {
         // we need to work of an array, so we need to see if anything was inserted/removed
         scope.$watch(function selectMultipleWatch() {
           if (!equals(lastView, ctrl.$viewValue)) {
-            lastView = copy(ctrl.$viewValue);
+            lastView = shallowCopy(ctrl.$viewValue);
             ctrl.$render();
           }
         });

src/ng/http.js

@@ -111,9 +111,9 @@ function $HttpProvider() {
       common: {
         'Accept': 'application/json, text/plain, */*'
       },
-      post:   copy(CONTENT_TYPE_APPLICATION_JSON),
-      put:    copy(CONTENT_TYPE_APPLICATION_JSON),
-      patch:  copy(CONTENT_TYPE_APPLICATION_JSON)
+      post:   shallowCopy(CONTENT_TYPE_APPLICATION_JSON),
+      put:    shallowCopy(CONTENT_TYPE_APPLICATION_JSON),
+      patch:  shallowCopy(CONTENT_TYPE_APPLICATION_JSON)
     },
 
     xsrfCookieName: 'XSRF-TOKEN',
@@ -946,7 +946,7 @@ function $HttpProvider() {
           } else {
             // serving from cache
             if (isArray(cachedResp)) {
-              resolvePromise(cachedResp[1], cachedResp[0], copy(cachedResp[2]), cachedResp[3]);
+              resolvePromise(cachedResp[1], cachedResp[0], shallowCopy(cachedResp[2]), cachedResp[3]);
             } else {
               resolvePromise(cachedResp, 200, {}, 'OK');
             }

src/ng/sce.js

@@ -737,7 +737,7 @@ function $SceProvider() {
         'document.  See http://docs.angularjs.org/api/ng.$sce for more information.');
     }
 
-    var sce = copy(SCE_CONTEXTS);
+    var sce = shallowCopy(SCE_CONTEXTS);
 
     /**
      * @ngdoc method

test/AngularSpec.js

@@ -219,6 +219,25 @@ describe('angular', function() {
       expect(clone.hello).toBeUndefined();
       expect(clone.goodbye).toBe("world");
     });
+
+    it('should handle arrays', function() {
+      var original = [{}, 1],
+          clone = [];
+
+      var aCopy = shallowCopy(original);
+      expect(aCopy).not.toBe(original);
+      expect(aCopy).toEqual(original);
+      expect(aCopy[0]).toBe(original[0]);
+
+      expect(shallowCopy(original, clone)).toBe(clone);
+      expect(clone).toEqual(original);
+    });
+
+    it('should handle primitives', function() {
+      expect(shallowCopy('test')).toBe('test');
+      expect(shallowCopy(3)).toBe(3);
+      expect(shallowCopy(true)).toBe(true);
+    });
   });
 
   describe('elementHTML', function() {