Add complete handler to Subscription, to handle the case when the ser…

src/Subscriptions.tsx

@@ -29,6 +29,7 @@ export interface SubscriptionProps<TData = any, TVariables = OperationVariables>
   shouldResubscribe?: any;
   client?: ApolloClient<Object>;
   onSubscriptionData?: (options: OnSubscriptionDataOptions<TData>) => any;
+  onSubscriptionComplete?: () => any;
   children?: (result: SubscriptionResult<TData>) => React.ReactNode;
 }
 
@@ -55,6 +56,7 @@ class Subscription<TData = any, TVariables = any> extends React.Component<
     variables: PropTypes.object,
     children: PropTypes.func,
     onSubscriptionData: PropTypes.func,
+    onSubscriptionComplete: PropTypes.func,
     shouldResubscribe: PropTypes.oneOfType([PropTypes.func, PropTypes.bool]),
   };
 
@@ -136,6 +138,7 @@ class Subscription<TData = any, TVariables = any> extends React.Component<
     this.querySubscription = this.queryObservable!.subscribe({
       next: this.updateCurrentData,
       error: this.updateError,
+      complete: this.completeSubscription
     });
   };
 
@@ -165,6 +168,15 @@ class Subscription<TData = any, TVariables = any> extends React.Component<
     });
   };
 
+  private completeSubscription = () => {
+    const {
+      client,
+      props: { onSubscriptionComplete },
+    } = this;
+    if (onSubscriptionComplete) onSubscriptionComplete();
+    this.endSubscription();
+  };
+
   private endSubscription = () => {
     if (this.querySubscription) {
       this.querySubscription.unsubscribe();