fix: observables were not emitting properly when the number of subscr…

…ibers changed mid-emit
simontonsoftware · Jul 15, 2019 · 4ad91fa · 4ad91fa
1 parent 7fd2733
commit 4ad91fa
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Showing 2 changed files with 14 additions and 1 deletion.
diff --git a/projects/ng-app-state/src/lib/store-object.spec.ts b/projects/ng-app-state/src/lib/store-object.spec.ts
@@ -190,6 +190,19 @@ describe("StoreObject", () => {
       counterStore.$.subscribe(spy);
       expectSingleCallAndReset(spy, 3);
     });
+
+    it("works when the number of subscribers changes mid-emit (production bug)", () => {
+      const spy = jasmine.createSpy();
+
+      store("counter")
+        .$.pipe(take(2))
+        .subscribe();
+      store("counter").$.subscribe(spy);
+      expectSingleCallAndReset(spy, 0);
+
+      store("counter").set(1);
+      expectSingleCallAndReset(spy, 1);
+    });
   });
 
   describe(".batch()", () => {

diff --git a/projects/ng-app-state/src/lib/tree-based-observable/observable-node.ts b/projects/ng-app-state/src/lib/tree-based-observable/observable-node.ts
@@ -74,7 +74,7 @@ export class ObservableNode extends Observable<any> {
   }
 
   private emit() {
-    for (const subscriber of this.subscribers) {
+    for (const subscriber of this.subscribers.slice()) {
       subscriber.next(this.value);
     }
   }