diff --git a/client-ts/Microsoft.AspNetCore.SignalR.Client.TS.Tests/HubConnection.spec.ts b/client-ts/Microsoft.AspNetCore.SignalR.Client.TS.Tests/HubConnection.spec.ts
index fc9cd990f9..32f7deda38 100644
--- a/client-ts/Microsoft.AspNetCore.SignalR.Client.TS.Tests/HubConnection.spec.ts
+++ b/client-ts/Microsoft.AspNetCore.SignalR.Client.TS.Tests/HubConnection.spec.ts
@@ -390,6 +390,32 @@ describe("HubConnection", () => {
             connection.receive({ type: 3, invocationId: connection.lastInvocationId });
             expect(await observer.completed).toEqual([1, 2, 3]);
         });
+
+        it("does not require error function registered", async () => {
+            let connection = new TestConnection();
+
+            let hubConnection = new HubConnection(connection);
+            let observer = hubConnection.stream("testMethod").subscribe({
+                next: val => { }
+            });
+
+            // Typically this would be called by the transport
+            // triggers observer.error()
+            connection.onclose(new Error("Connection lost"));
+        });
+
+        it("does not require complete function registered", async () => {
+            let connection = new TestConnection();
+
+            let hubConnection = new HubConnection(connection);
+            let observer = hubConnection.stream("testMethod").subscribe({
+                next: val => { }
+            });
+
+            // Send completion to trigger observer.complete()
+            // Expectation is connection.receive will not to throw
+            connection.receive({ type: 3, invocationId: connection.lastInvocationId });
+        });
     });
 
     describe("onClose", () => {
diff --git a/client-ts/Microsoft.AspNetCore.SignalR.Client.TS.Tests/JasmineUtils.ts b/client-ts/Microsoft.AspNetCore.SignalR.Client.TS.Tests/JasmineUtils.ts
index be452ac96f..c2d3368556 100644
--- a/client-ts/Microsoft.AspNetCore.SignalR.Client.TS.Tests/JasmineUtils.ts
+++ b/client-ts/Microsoft.AspNetCore.SignalR.Client.TS.Tests/JasmineUtils.ts
@@ -7,7 +7,10 @@ export function asyncit(expectation: string, assertion?: () => Promise<any>, tim
         testFunction = done => {
             assertion()
                 .then(() => done())
-                .catch(() => fail());
+                .catch((err) => {
+                    fail(err);
+                    done();
+                });
         };
     }
 
diff --git a/client-ts/Microsoft.AspNetCore.SignalR.Client.TS/Observable.ts b/client-ts/Microsoft.AspNetCore.SignalR.Client.TS/Observable.ts
index 105b01b8d4..e2ea7cb11e 100644
--- a/client-ts/Microsoft.AspNetCore.SignalR.Client.TS/Observable.ts
+++ b/client-ts/Microsoft.AspNetCore.SignalR.Client.TS/Observable.ts
@@ -6,8 +6,8 @@
 export interface Observer<T> {
     closed?: boolean;
     next: (value: T) => void;
-    error: (err: any) => void;
-    complete: () => void;
+    error?: (err: any) => void;
+    complete?: () => void;
 }
 
 export interface Observable<T> {
@@ -30,13 +30,17 @@ export class Subject<T> implements Observable<T> {
 
     public error(err: any): void {
         for (let observer of this.observers) {
-            observer.error(err);
+            if (observer.error) {
+                observer.error(err);
+            }
         }
     }
 
     public complete(): void {
         for (let observer of this.observers) {
-            observer.complete();
+            if (observer.complete) {
+                observer.complete();
+            }
         }
     }