feat($state): allowing transition to replace URL

Closes #409

Author: nateabele

src/state.js

@@ -388,6 +388,10 @@ function $StateProvider(   $urlRouterProvider,   $urlMatcherFactory,           $
         var toNav = to.navigable;
         if (options.location && toNav) {
           $location.url(toNav.url.format(toNav.locals.globals.$stateParams));
+
+          if (options.location === 'replace') {
+            $location.replace();
+          }
         }
 
         $rootScope.$broadcast('$stateChangeSuccess', to.self, toParams, from.self, fromParams);

test/stateSpec.js

@@ -608,6 +608,38 @@ describe('state', function () {
       $rootScope.$apply();
       expect($state.current.name).toBe('');
     }));
+
+    it('should replace browser history when "replace" enabled', inject(function ($state, $rootScope, $location, $q) {
+      var originalReplaceFn = $location.replace, replaceWasCalled = false;
+
+      // @todo Replace this with a spy
+      var decoratedReplaceFn = function() {
+        replaceWasCalled = true;
+        originalReplaceFn.call($location);
+      };
+      $location.replace = decoratedReplaceFn;
+
+      $state.transitionTo('about', {}, { location: 'replace' });
+      $q.flush();
+
+      expect(replaceWasCalled).toEqual(true);
+    }));
+
+    it('should not replace history normally', inject(function ($state, $rootScope, $location, $q) {
+      var originalReplaceFn = $location.replace, replaceWasCalled = false;
+
+      // @todo Replace with spy
+      var decoratedReplaceFn = function() {
+        replaceWasCalled = true;
+        originalReplaceFn.call($location);
+      };
+      $location.replace = decoratedReplaceFn;
+
+      $state.transitionTo('about');
+      $q.flush();
+
+      expect(replaceWasCalled).toEqual(false);
+    }));
   });
 
   describe('default properties', function() {