From 7559b9ec714b8714bf3f24cc4164b94b6877e3ab Mon Sep 17 00:00:00 2001
From: "JiaLi.Passion" <JiaLi.Passion@gmail.com>
Date: Sat, 28 Apr 2018 13:26:47 +0800
Subject: [PATCH] fix(core): use then directly when promise is not patchable

---
 lib/zone.ts | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lib/zone.ts b/lib/zone.ts
index 9cbd04fdc..f39cc4c2d 100644
--- a/lib/zone.ts
+++ b/lib/zone.ts
@@ -1272,7 +1272,13 @@ const Zone: ZoneType = (function(global: any) {
         }
       }
       if (nativeMicroTaskQueuePromise) {
-        nativeMicroTaskQueuePromise[symbolThen](drainMicroTaskQueue);
+        let nativeThen = nativeMicroTaskQueuePromise[symbolThen];
+        if (!nativeThen) {
+          // native Promise is not patchable, we need to use `then` directly
+          // issue 1078
+          nativeThen = nativeMicroTaskQueuePromise['then'];
+        }
+        nativeThen.call(nativeMicroTaskQueuePromise, drainMicroTaskQueue);
       } else {
         global[symbolSetTimeout](drainMicroTaskQueue, 0);
       }