diff --git a/modules/@angular/router/src/router_config_loader.ts b/modules/@angular/router/src/router_config_loader.ts
index 1643068ab69c..fe27915e261a 100644
--- a/modules/@angular/router/src/router_config_loader.ts
+++ b/modules/@angular/router/src/router_config_loader.ts
@@ -44,10 +44,13 @@ export class RouterConfigLoader {
     if (typeof loadChildren === 'string') {
       return fromPromise(this.loader.load(loadChildren));
     } else {
-      const offlineMode = this.compiler instanceof Compiler;
-      return mergeMap.call(
-          wrapIntoObservable(loadChildren()),
-          (t: any) => offlineMode ? of (<any>t) : fromPromise(this.compiler.compileModuleAsync(t)));
+      return mergeMap.call(wrapIntoObservable(loadChildren()), (t: NgModuleFactory<any>| any) => {
+        if (t instanceof NgModuleFactory) {
+          return of (t);
+        } else {
+          return fromPromise(this.compiler.compileModuleAsync(t));
+        }
+      });
     }
   }
 }