events-backend: proper cleanup of signal abort listeners

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/events-backend/src/service/hub/DatabaseEventBusStore.ts

@@ -109,14 +109,31 @@ class DatabaseEventBusListener {
     await this.#ensureConnection();
 
     const updatePromise = new Promise<{ topic: string }>((resolve, reject) => {
-      const listener = { topics, resolve, reject };
+      const listener = {
+        topics,
+        resolve(result: { topic: string }) {
+          resolve(result);
+          cleanup();
+        },
+        reject(err: Error) {
+          reject(err);
+          cleanup();
+        },
+      };
       this.#listeners.add(listener);
 
-      signal.addEventListener('abort', () => {
+      const onAbort = () => {
         this.#listeners.delete(listener);
         this.#maybeTimeoutConnection();
         reject(signal.reason);
-      });
+        cleanup();
+      };
+
+      function cleanup() {
+        signal.removeEventListener('abort', onAbort);
+      }
+
+      signal.addEventListener('abort', onAbort);
     });
 
     // Ignore unhandled rejections

plugins/events-backend/src/service/hub/MemoryEventBusStore.ts

@@ -115,13 +115,26 @@ export class MemoryEventBusStore implements EventBusStore {
         }
 
         return new Promise<{ topic: string }>((resolve, reject) => {
-          const listener = { topics: sub.topics, resolve };
+          const listener = {
+            topics: sub.topics,
+            resolve(result: { topic: string }) {
+              resolve(result);
+              cleanup();
+            },
+          };
           this.#listeners.add(listener);
 
-          options.signal.addEventListener('abort', () => {
+          const onAbort = () => {
             this.#listeners.delete(listener);
             reject(options.signal.reason);
-          });
+            cleanup();
+          };
+
+          function cleanup() {
+            options.signal.removeEventListener('abort', onAbort);
+          }
+
+          options.signal.addEventListener('abort', onAbort);
         });
       },
     };