Implemented a fix for the setTimeout unsubscribe thing

src/core/ObservableQuery.ts

@@ -103,18 +103,37 @@ export class ObservableQuery<T> extends Observable<ApolloQueryResult<T>> {
   }
 
   public result(): Promise<ApolloQueryResult<T>> {
+    const that = this;
     return new Promise((resolve, reject) => {
-      const subscription = this.subscribe({
+      let subscription: (Subscription | null) = null;
+      const observer: Observer<ApolloQueryResult<T>> = {
         next(result) {
           resolve(result);
+
+          // Stop the query within the QueryManager if we can before
+          // this function returns.
+          //
+          // We do this in order to prevent observers piling up within
+          // the QueryManager. Notice that we only fully unsubscribe
+          // from the subscription in a setTimeout(..., 0)  call. This call can
+          // actually be handled by the browser at a much later time. If queries
+          // are fired in the meantime, observers that should have been removed
+          // from the QueryManager will continue to fire, causing an unnecessary
+          // performance hit.
+          const selectedObservers = that.observers.filter((obs: Observer<ApolloQueryResult<T>>) => obs !== observer);
+          if (selectedObservers.length === 0) {
+            that.queryManager.removeQuery(that.queryId);
+          }
+
           setTimeout(() => {
-            subscription.unsubscribe();
+            (subscription as Subscription).unsubscribe();
           }, 0);
         },
         error(error) {
           reject(error);
         },
-      });
+      };
+      subscription = that.subscribe(observer);
     });
   }
 

src/core/QueryManager.ts

@@ -884,11 +884,15 @@ export class QueryManager {
     });
   }
 
+  public removeQuery(queryId: string) {
+    delete this.queryListeners[queryId];
+    delete this.queryDocuments[queryId];
+  }
+
   public stopQuery(queryId: string) {
     // XXX in the future if we should cancel the request
     // so that it never tries to return data
-    delete this.queryListeners[queryId];
-    delete this.queryDocuments[queryId];
+    this.removeQuery(queryId);
     this.stopQueryInStore(queryId);
   }