Refactor isJson()

src/Angular.js

@@ -141,6 +141,11 @@ function isElement(node) {
   return node && (node.nodeName || node instanceof JQLite || (jQuery && node instanceof jQuery));
 }
 
+function isJson(value) {
+  return isString(value) && (/^\s*\{/.test(value) && /\}\s*$/.test(value) || 
+      /^\s*\[/.test(value) && /\]\s*$/.test(value));
+}
+
 function HTML(html) {
   this.html = html;
 }

src/services.js

@@ -417,7 +417,7 @@ angularServiceInject('$xhr', function($browser, $error, $log){
     }
     $browser.xhr(method, url, post, function(code, response){
       try {
-        if (isString(response) && /^\s*[\[\{]/.exec(response) && /[\}\]]\s*$/.exec(response)) {
+        if (isJson(response)) {
           response = fromJson(response);
         }
         if (code == 200) {

test/AngularSpec.js

@@ -250,3 +250,24 @@ describe('angularJsConfig', function() {
                                           ie_compat_id: 'ng-ie-compat'});
   });
 });
+
+describe('isJson', function() {
+  it('should return false on non-string', function() {
+    expect(isJson()).toBeFalsy();
+    expect(isJson({})).toBeFalsy();
+    expect(isJson([])).toBeFalsy();
+    expect(isJson(10)).toBeFalsy();
+  });
+
+  it('should return true on strings starting and ending with curly or square brackets', function() {
+    expect(isJson('{a: "b"}')).toBeTruthy();
+    expect(isJson('[1, 2, 3]')).toBeTruthy();
+    expect(isJson('\t\n{a: "b"} ')).toBeTruthy();
+    expect(isJson(' [1, 2, 3] ')).toBeTruthy();
+  });
+
+  it('should return false on other strings', function() {
+    expect(isJson('{ ]')).toBeFalsy();
+    expect(isJson(' abc ')).toBeFalsy();
+  });
+});