From af32e48bffec2f909f184c365323bd7115d43f6f Mon Sep 17 00:00:00 2001
From: Ben Lesh <ben@benlesh.com>
Date: Fri, 4 Feb 2022 17:13:12 -0600
Subject: [PATCH] fix(subscribe): allows functions where bind has been patched
 to be weird

Apparently, code exists in the wild that will patch function bind to do something other than return a function that will execute the function instance, so we cannot rely on bind.

Resolves #6783
---
 spec/Observable-spec.ts    | 28 ++++++++++++++++++++++++++++
 src/internal/Subscriber.ts |  6 +++---
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/spec/Observable-spec.ts b/spec/Observable-spec.ts
index 630cd5085d..672a724c6b 100644
--- a/spec/Observable-spec.ts
+++ b/spec/Observable-spec.ts
@@ -191,6 +191,34 @@ describe('Observable', () => {
   });
 
   describe('subscribe', () => {
+    it('should work with handlers with hacked bind methods', () => {
+      const source = of('Hi');
+      const results: any[] = [];
+      const next = function (value: string) {
+        results.push(value);
+      }
+      next.bind = () => { /* lol */};
+      
+      const complete = function () {
+        results.push('done');
+      }
+      complete.bind = () => { /* lol */};
+
+      source.subscribe({ next, complete });
+      expect(results).to.deep.equal(['Hi', 'done']);
+    });
+
+    it('should work with handlers with hacked bind methods, in the error case', () => {
+      const source = throwError(() => 'an error');
+      const results: any[] = [];
+      const error = function (value: string) {
+        results.push(value);
+      }
+
+      source.subscribe({ error });
+      expect(results).to.deep.equal(['an error']);
+    });
+
     it('should be synchronous', () => {
       let subscribed = false;
       let nexted: string;
diff --git a/src/internal/Subscriber.ts b/src/internal/Subscriber.ts
index de010710d3..5413f40e01 100644
--- a/src/internal/Subscriber.ts
+++ b/src/internal/Subscriber.ts
@@ -166,9 +166,9 @@ export class SafeSubscriber<T> extends Subscriber<T> {
       } else {
         context = observerOrNext;
       }
-      next = next?.bind(context);
-      error = error?.bind(context);
-      complete = complete?.bind(context);
+      next = next && ((value: T) => context.next(value));
+      error = error && ((err: any) => context.error(err));
+      complete = complete && (() => context.complete());
     }
 
     // Once we set the destination, the superclass `Subscriber` will