From 269b89603485a83cc58a44bef9bdfe830918789c Mon Sep 17 00:00:00 2001
From: JiaLiPassion <JiaLi.Passion@gmail.com>
Date: Mon, 30 Apr 2018 12:24:55 +0800
Subject: [PATCH] fix unpatch bug

---
 lib/common/utils.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/common/utils.ts b/lib/common/utils.ts
index 8ebc98524..2955e4318 100644
--- a/lib/common/utils.ts
+++ b/lib/common/utils.ts
@@ -459,7 +459,8 @@ export function generateUnPatchAndRePatch(patches: [{target: any, methods: strin
     unPatchFn: () => {
       patches.forEach(patch => {
         patch.methods.forEach(m => {
-          const originalDelegate = patch.target[zoneSymbol(m)];
+          const method = patch.target[m];
+          const originalDelegate = method && (method as any)[zoneSymbol('OriginalDelegate')];
           if (originalDelegate) {
             patch.target[m] = originalDelegate;
           }