Basic push notification system for service alerts

Co-authored-by: Copilot <copilot@github.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/frontend/app/hooks/useFavorites.ts b/src/frontend/app/hooks/useFavorites.ts
index 962ac2d..0eceba9 100644
--- a/src/frontend/app/hooks/useFavorites.ts
+++ b/src/frontend/app/hooks/useFavorites.ts
@@ -1,7 +1,10 @@
 import { useState } from "react";
+import { writeFavorites } from "~/utils/idb";
 
 /**
  * A simple hook for managing favorite items in localStorage.
+ * Also mirrors changes to IndexedDB so the service worker can filter push
+ * notifications by favourites without access to localStorage.
  * @param key LocalStorage key to use
  * @returns [favorites, toggleFavorite, isFavorite]
  */
@@ -18,6 +21,9 @@ export function useFavorites(key: string) {
         ? prev.filter((item) => item !== id)
         : [...prev, id];
       localStorage.setItem(key, JSON.stringify(next));
+      writeFavorites(key, next).catch(() => {
+        /* best-effort */
+      });
       return next;
     });
   };