fix(WebSocketSubject): prevent early close (#1831)

spec/observables/dom/webSocket-spec.ts

@@ -436,5 +436,56 @@ describe('Observable.webSocket', () => {
 
       expect(results).to.deep.equal(['sub', 'unsub', 'sub', error, 'unsub']);
     });
+
+    it('should not close the socket until all subscriptions complete', () => {
+      const socketSubject = Rx.Observable.webSocket(<any>{url: 'ws://mysocket'});
+      const results = [];
+      const socketMessages = [
+        {id: 'A'},
+        {id: 'B'},
+        {id: 'A', complete: true},
+        {id: 'B'},
+        {id: 'B', complete: true},
+      ];
+
+      socketSubject.multiplex(
+        () => 'no-op',
+        () => results.push('A unsub'),
+        (req: any) => req.id === 'A')
+        .takeWhile((req: any) => !req.complete)
+        .subscribe(
+          () => results.push('A next'),
+          (e) => results.push('A error ' + e),
+          () => results.push('A complete')
+        );
+
+      socketSubject.multiplex(
+        () => 'no-op',
+        () => results.push('B unsub'),
+        (req: any) => req.id === 'B')
+        .takeWhile((req: any) => !req.complete)
+        .subscribe(
+          () => results.push('B next'),
+          (e) => results.push('B error ' + e),
+          () => results.push('B complete')
+        );
+
+      // Setup socket and send messages
+      let socket = MockWebSocket.lastSocket;
+      socket.open();
+      socketMessages.forEach((msg) => {
+        socket.triggerMessage(JSON.stringify(msg));
+      });
+
+      expect(results).to.deep.equal([
+        'A next',
+        'B next',
+        'A complete',
+        'A unsub',
+        'B next',
+        'B complete',
+        'B unsub',
+      ]);
+    });
   });
-});
+});

src/observable/dom/WebSocketSubject.ts

@@ -203,7 +203,7 @@ export class WebSocketSubject<T> extends AnonymousSubject<T> {
     subscription.add(this._output.subscribe(subscriber));
     subscription.add(() => {
       const { socket } = this;
-      if (socket && socket.readyState === 1) {
+      if (this._output.observers.length === 0 && socket && socket.readyState === 1) {
         socket.close();
         this.socket = null;
       }