[SID-2056] React SDK: back button blocked

.changeset/curvy-owls-repair.md

@@ -0,0 +1,5 @@
+---
+"@slashid/react": patch
+---
+
+Fixed: event buffer wasn't buffering events after all subscribers stopped listening for a particular event

packages/react/src/components/form/event-buffer.test.ts

@@ -85,6 +85,44 @@ describe("createEventBuffer", () => {
     expect(callback).toHaveBeenCalledTimes(1);
   });
 
+  it("should buffer events after all subscribers unsubscribe from an event and replay them to the first subscriber", () => {
+    const sdk = new MockSlashID({ analyticsEnabled: false, oid: "test" });
+    const eventBuffer = createEventBuffer({ sdk });
+    const callback = vi.fn();
+
+    // subscribe
+    eventBuffer.subscribe("authnContextUpdateChallengeReceivedEvent", callback);
+
+    sdk.mockPublish("authnContextUpdateChallengeReceivedEvent", {
+      targetOrgId: "1",
+    });
+
+    // unsubscribe
+    eventBuffer.unsubscribe(
+      "authnContextUpdateChallengeReceivedEvent",
+      callback
+    );
+    sdk.mockPublish("authnContextUpdateChallengeReceivedEvent", {
+      targetOrgId: "2",
+    });
+
+    expect(callback).toHaveBeenLastCalledWith({
+      targetOrgId: "1",
+    });
+    expect(callback).toHaveBeenCalledTimes(1);
+
+    // subscribe again
+    // there was a bug where we incorrectly managed internal state and didn't buffer events after the last subscriber unsubscribed
+    eventBuffer.subscribe("authnContextUpdateChallengeReceivedEvent", callback);
+
+    // this should replay the event that was missed
+
+    expect(callback).toHaveBeenLastCalledWith({
+      targetOrgId: "2",
+    });
+    expect(callback).toHaveBeenCalledTimes(2);
+  });
+
   it("should only let the first subscriber consume the buffered events", () => {
     const sdk = new MockSlashID({ analyticsEnabled: false, oid: "test" });
     const eventBuffer = createEventBuffer({ sdk });

packages/react/src/components/form/event-buffer.ts

@@ -26,7 +26,10 @@ export function createEventBuffer({ sdk }: CreateEventBufferArgs): EventBuffer {
   Utils.PUBLIC_READ_EVENTS.forEach((publicReadEventName: EventNames) => {
     // create an event handler
     const handler = (event: Event) => {
-      if (subscribers.has(publicReadEventName)) {
+      if (
+        subscribers.has(publicReadEventName) &&
+        subscribers.get(publicReadEventName)?.length
+      ) {
         // if there is a subscriber for this event type just ignore
         return;
       }
@@ -79,7 +82,7 @@ export function createEventBuffer({ sdk }: CreateEventBufferArgs): EventBuffer {
   function unsubscribe(eventType: EventNames, callback: EventCallback) {
     sdk.unsubscribe(eventType, callback);
 
-    if (!subscribers.has(eventType)) {
+    if (!subscribers.has(eventType) || !subscribers.get(eventType)?.length) {
       return;
     }