From 3b8cf948246158966ab8b8ec2a94d49a7acac45e Mon Sep 17 00:00:00 2001
From: OJ Kwon <kwon.ohjoong@gmail.com>
Date: Wed, 25 Nov 2015 11:19:47 -0800
Subject: [PATCH] fix(expand): terminate recursive call when destination
 completes

relates to #766
---
 src/operators/expand-support.ts | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/operators/expand-support.ts b/src/operators/expand-support.ts
index 7b16b1969b..187f4f624f 100644
--- a/src/operators/expand-support.ts
+++ b/src/operators/expand-support.ts
@@ -33,12 +33,19 @@ export class ExpandSubscriber<T, R> extends OuterSubscriber<T, R> {
   }
 
   _next(value: any): void {
+    const destination = this.destination;
+
+    if (destination.isUnsubscribed) {
+      this._complete();
+      return;
+    }
+
     const index = this.index++;
     if (this.active < this.concurrent) {
-      this.destination.next(value);
+      destination.next(value);
       let result = tryCatch(this.project)(value, index);
       if (result === errorObject) {
-        this.destination.error(result.e);
+        destination.error(result.e);
       } else {
         if (result._isScalar) {
           this._next(result.value);