diff --git a/lib/zone.ts b/lib/zone.ts
index 4edfad99d..4ca3384f2 100644
--- a/lib/zone.ts
+++ b/lib/zone.ts
@@ -665,7 +665,9 @@ const Zone: ZoneType = (function(global: any) {
   }
 
   const detectAsyncFunction = async function() {};
-  const AsyncFunction = (detectAsyncFunction.constructor as any).name === 'AsyncFunction' ? detectAsyncFunction.constructor : null;
+  const AsyncFunction = (detectAsyncFunction.constructor as any).name === 'AsyncFunction' ?
+      detectAsyncFunction.constructor :
+      null;
 
   class Zone implements AmbientZone {
     static __symbol__: (name: string) => string = __symbol__;