feat(router): allow async routes to be defined with "loader"

modules/angular2/src/router/route_config_nomalizer.ts

@@ -13,10 +13,13 @@ export function normalizeRouteConfig(config: RouteDefinition): RouteDefinition {
     return <RouteDefinition>config;
   }
 
-  if ((!config.component) == (!config.redirectTo)) {
+  if ((+!!config.component) + (+!!config.redirectTo) + (+!!config.loader) != 1) {
     throw new BaseException(
         `Route config should contain exactly one "component", "loader", or "redirectTo" property.`);
   }
+  if (config.loader) {
+    return new AsyncRoute({path: config.path, loader: config.loader, as: config.as});
+  }
   if (config.component) {
     if (typeof config.component == 'object') {
       let componentDefinitionObject = <ComponentDefinition>config.component;

modules/angular2/test/router/route_config_spec.ts

@@ -100,6 +100,22 @@ export function main() {
        }));
 
 
+    it('should work in an app with async components defined with "loader"',
+       inject([AsyncTestCompleter], (async) => {
+         bootstrap(ConciseAsyncAppCmp,
+                   [bind(ROUTER_PRIMARY_COMPONENT).toValue(AsyncAppCmp), testBindings])
+             .then((applicationRef) => {
+               var router = applicationRef.hostComponent.router;
+               router.subscribe((_) => {
+                 expect(el).toHaveText('root { hello }');
+                 expect(applicationRef.hostComponent.location.path()).toEqual('/hello');
+                 async.done();
+               });
+               router.navigateByUrl('/hello');
+             });
+       }));
+
+
     it('should work in an app with a constructor component',
        inject([AsyncTestCompleter], (async) => {
          bootstrap(
@@ -187,6 +203,15 @@ class AsyncAppCmp {
   constructor(public router: Router, public location: LocationStrategy) {}
 }
 
+@Component({selector: 'app-cmp'})
+@View({template: `root { <router-outlet></router-outlet> }`, directives: ROUTER_DIRECTIVES})
+@RouteConfig([
+  {path: '/hello', loader: HelloLoader},
+])
+class ConciseAsyncAppCmp {
+  constructor(public router: Router, public location: LocationStrategy) {}
+}
+
 @Component({selector: 'app-cmp'})
 @View({template: `root { <router-outlet></router-outlet> }`, directives: ROUTER_DIRECTIVES})
 @RouteConfig([