type PeriodicSyncRegistration = ServiceWorkerRegistration & {
periodicSync: { register: (tag: string, options: { minInterval: number }) => Promise<void> };
};
export const schedulePeriodicRefresh = async (tag: string, minIntervalMs: number): Promise<boolean> => {Schedule light refresh work that can survive transient network loss.
type SyncRegistration = ServiceWorkerRegistration & { sync: { register: (tag: string) => Promise<void> } };
export const scheduleOfflineAction = async (tag: string, replayNow: () => Promise<void>): Promise<void> => {
const registration = await navigator.serviceWorker.ready;
const canBackgroundSync = "sync" in registration;Replay user actions later when connectivity returns with Background Sync.
const CACHE_NAME = "app-shell-v1";
const PRECACHE_URLS = ["/", "/styles.css", "/app.js", "/offline.html"];
self.addEventListener("install", (event) => {
(event as Event & { waitUntil: (p: Promise<unknown>) => void }).waitUntil(Precache the app shell on install and serve every request from cache first, falling back to the network only on a cache miss.