feat(notifications): web push opt-in + unread nav badges

Surfaces three events without a full notification center:
- service worker (public/sw.js) gains push + notificationclick handlers
  (RTL, focuses an existing tab or opens the target URL).
- usePushNotifications hook: permission + VAPID subscribe/unsubscribe
  against the backend push endpoints.
- opt-in UI both ways: a one-time dismissible post-login banner
  (PushPermissionBanner, rendered in MyLayout) and a permanent toggle
  (PushSettingToggle) on buyer profile settings and seller store settings.
- useBadgeCounts polls /api/notif/v1/badges/; small red badges on the
  bottom-nav profile icon (chat + order updates), the profile sidebar
  (پیام‌ها / سفارش‌ها) and the seller dashboard sidebar. Visiting orders
  clears its badge.

Degrades gracefully: if the backend endpoints are absent the counts fall
back to zero and nothing throws.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/components/MyLayout.tsx

@@ -14,6 +14,8 @@ import { detectPage } from "~/utils/helpers";
 import { useRootData } from "~/hooks/use-root-data";
 import { useCartCount } from "~/requestHandler/use-cart-hooks";
 import { useSellerOrderCount } from "~/requestHandler/use-order-hooks";
+import { useBadgeCounts } from "~/hooks/useBadgeCounts";
+import { PushPermissionBanner } from "~/components/notifications/PushPermissionBanner";
 import settingIconFilled from "~/assets/icons/navbar/setting-filled.svg";
 import settingIconOutline from "~/assets/icons/navbar/setting-outline.svg";
 import documentFilled from "~/assets/icons/navbar/document-filled.svg";
@@ -73,6 +75,7 @@ const MyLayout = React.memo(({ children }: { children: React.ReactNode }) => {
           ) : (
             <MobileBottomNavigation hideOnDesktop={expandOnDesktop} />
           )}
+          <PushPermissionBanner />
         </div>
       </div>
       {isDesktopReady && <DesktopFooter />}
@@ -97,6 +100,11 @@ const MobileBottomNavigation = ({
   const { user } = useRootData();
   const [isStoreMode, setIsStoreMode] = useState(false);
   const sellerOrderCount = useSellerOrderCount(!!isStoreMode);
+  const { data: badgeCounts } = useBadgeCounts();
+  // Buyer-facing account activity (unread chats + order status changes) is
+  // surfaced on the profile icon, since both live under /profile.
+  const accountUnread =
+    (badgeCounts?.chat || 0) + (badgeCounts?.order_updates || 0);
   const [storeId, setStoreId] = useState<string | null>(null);
 
   // Initialize state from sessionStorage on mount - only once
@@ -303,6 +311,8 @@ const MobileBottomNavigation = ({
               : theme === "dark"
                 ? profileFilled
                 : profileOutline,
+          badge:
+            accountUnread > 0 && user?.access_token ? accountUnread : null,
         },
         {
           link: "/cart",
@@ -344,6 +354,7 @@ const MobileBottomNavigation = ({
     currentPage,
     cartCount,
     sellerOrderCount,
+    accountUnread,
     user?.access_token,
     isStoreMode,
     storeId,
@@ -374,11 +385,11 @@ const MobileBottomNavigation = ({
             ) : (
               item.icon
             )}
-            {item.badge && (
+            {item.badge ? (
-              <span className="absolute -top-1 -right-1  text-R12 ">
+              <span className="absolute -top-1.5 -right-1.5 min-w-[16px] h-4 px-1 rounded-full bg-RED text-white text-[10px] font-bold flex items-center justify-center leading-none">
-                {item.badge}
+                {item.badge > 99 ? "99+" : item.badge}
               </span>
-            )}
+            ) : null}
           </Link>
         ))}
       </div>

app/components/notifications/PushPermissionBanner.tsx

@@ -0,0 +1,67 @@
+import { useEffect, useState } from "react";
+import { Bell, X } from "lucide-react";
+import { useRootData } from "~/hooks/use-root-data";
+import { usePushNotifications } from "~/hooks/usePushNotifications";
+
+const DISMISS_KEY = "push_banner_dismissed";
+
+/**
+ * One-time, dismissible bar prompting logged-in users to enable web push.
+ * Shown only when: logged in, push is supported, permission not yet decided,
+ * and the user hasn't dismissed or already subscribed. A permanent toggle in
+ * settings lets them change their mind later.
+ */
+export function PushPermissionBanner() {
+  const { user } = useRootData();
+  const { supported, permission, isSubscribed, subscribe, busy } =
+    usePushNotifications();
+  const [visible, setVisible] = useState(false);
+
+  useEffect(() => {
+    if (typeof window === "undefined") return;
+    const dismissed = localStorage.getItem(DISMISS_KEY) === "1";
+    setVisible(
+      !!user?.access_token &&
+        supported &&
+        permission === "default" &&
+        !isSubscribed &&
+        !dismissed
+    );
+  }, [user?.access_token, supported, permission, isSubscribed]);
+
+  if (!visible) return null;
+
+  const dismiss = () => {
+    localStorage.setItem(DISMISS_KEY, "1");
+    setVisible(false);
+  };
+
+  const enable = async () => {
+    const ok = await subscribe();
+    // Whether granted or denied, don't nag again from the banner.
+    localStorage.setItem(DISMISS_KEY, "1");
+    setVisible(false);
+    return ok;
+  };
+
+  return (
+    <div className="fixed bottom-[calc(58px+env(safe-area-inset-bottom))] lg:bottom-4 left-1/2 -translate-x-1/2 z-40 w-[92%] max-w-md lg:max-w-sm">
+      <div className="flex items-center gap-3 rounded-2xl bg-BLACK text-white shadow-lg px-4 py-3">
+        <Bell size={20} className="shrink-0" />
+        <p className="text-[13px] leading-5 flex-1">
+          اعلان‌ها را فعال کنید تا از پیام‌ها و وضعیت سفارش‌ها باخبر شوید.
+        </p>
+        <button
+          onClick={enable}
+          disabled={busy}
+          className="shrink-0 rounded-xl bg-VITROWN_BLUE px-3 py-1.5 text-[13px] font-bold disabled:opacity-60"
+        >
+          {busy ? "..." : "فعال‌سازی"}
+        </button>
+        <button onClick={dismiss} aria-label="بستن" className="shrink-0 opacity-70">
+          <X size={18} />
+        </button>
+      </div>
+    </div>
+  );
+}

app/components/notifications/PushSettingToggle.tsx

@@ -0,0 +1,50 @@
+import { usePushNotifications } from "~/hooks/usePushNotifications";
+
+/**
+ * A settings row with a switch to enable/disable web push notifications.
+ * Mirrors the existing theme-toggle row styling on the settings pages.
+ */
+export function PushSettingToggle({ className = "" }: { className?: string }) {
+  const { supported, permission, isSubscribed, subscribe, disable, busy } =
+    usePushNotifications();
+
+  const blocked = permission === "denied";
+  const checked = isSubscribed && permission === "granted";
+
+  const onToggle = () => {
+    if (busy || blocked) return;
+    if (checked) {
+      disable();
+    } else {
+      subscribe();
+    }
+  };
+
+  return (
+    <div className={className}>
+      <div className="flex w-full items-center justify-between">
+        <div className="flex flex-col gap-1">
+          <p className="text-R12 lg:text-B16 font-bold">اعلان‌ها</p>
+          <p className="text-R10 lg:text-R12 text-GRAY">
+            {blocked
+              ? "اعلان‌ها در مرورگر مسدود شده‌اند. از تنظیمات مرورگر اجازه دهید."
+              : !supported
+                ? "مرورگر شما از اعلان پشتیبانی نمی‌کند."
+                : "دریافت اعلان برای پیام‌ها و وضعیت سفارش‌ها"}
+          </p>
+        </div>
+        <label className="relative inline-flex items-center cursor-pointer">
+          <input
+            type="checkbox"
+            checked={checked}
+            onChange={onToggle}
+            disabled={busy || blocked || !supported}
+            className="sr-only peer"
+            aria-label="اعلان‌ها"
+          />
+          <div className="w-11 h-6 bg-WHITE2 peer-focus:outline-none rounded-full peer peer-checked:after:translate-x-full peer-checked:after:border-WHITE after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-WHITE after:border-GRAY3 after:border after:rounded-full after:h-5 after:w-5 after:transition-all peer-checked:bg-VITROWN_BLUE border peer-disabled:opacity-50"></div>
+        </label>
+      </div>
+    </div>
+  );
+}

app/hooks/useBadgeCounts.ts

@@ -0,0 +1,67 @@
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { useAuthToken } from "./use-root-data";
+import { getApiBaseUrl } from "~/utils/api-config";
+
+export interface BadgeCounts {
+  chat: number;
+  order_updates: number;
+  seller_orders: number;
+}
+
+const EMPTY: BadgeCounts = { chat: 0, order_updates: 0, seller_orders: 0 };
+
+export const badgeKeys = {
+  all: ["notif-badges"] as const,
+};
+
+/**
+ * Polls unread counts for the nav badges (chat / buyer order updates / seller
+ * new orders). Lightweight: a single endpoint, refetched on an interval and
+ * when the tab regains focus.
+ */
+export function useBadgeCounts() {
+  const token = useAuthToken();
+  const apiBase = getApiBaseUrl();
+
+  return useQuery({
+    queryKey: badgeKeys.all,
+    enabled: !!token,
+    refetchInterval: 30000,
+    refetchOnWindowFocus: true,
+    queryFn: async (): Promise<BadgeCounts> => {
+      if (!token) return EMPTY;
+      const res = await fetch(`${apiBase}/api/notif/v1/badges/`, {
+        headers: { Authorization: `Bearer ${token}` },
+      });
+      if (!res.ok) return EMPTY;
+      return (await res.json()) as BadgeCounts;
+    },
+  });
+}
+
+/**
+ * Marks a badge category ("order_updates" | "seller_orders") as read, then
+ * refreshes the counts. Chat clears via the existing per-thread read flow.
+ */
+export function useMarkBadgeRead() {
+  const token = useAuthToken();
+  const apiBase = getApiBaseUrl();
+  const queryClient = useQueryClient();
+
+  return useMutation({
+    mutationFn: async (category: "order_updates" | "seller_orders") => {
+      if (!token) return;
+      await fetch(`${apiBase}/api/notif/v1/badges/mark-read/`, {
+        method: "POST",
+        headers: {
+          "Content-Type": "application/json",
+          Authorization: `Bearer ${token}`,
+        },
+        body: JSON.stringify({ category }),
+      });
+    },
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: badgeKeys.all });
+    },
+  });
+}

app/hooks/usePushNotifications.ts

@@ -0,0 +1,129 @@
+import { useCallback, useEffect, useState } from "react";
+import { useAuthToken } from "./use-root-data";
+import { getApiBaseUrl } from "~/utils/api-config";
+
+/**
+ * Web Push subscription management.
+ *
+ * Flow: ask permission -> fetch VAPID public key -> subscribe via the service
+ * worker's PushManager -> POST the subscription to the backend. Disabling
+ * unsubscribes locally and tells the backend to drop the row.
+ */
+
+type PermissionState = NotificationPermission | "unsupported";
+
+function urlBase64ToUint8Array(base64String: string): Uint8Array<ArrayBuffer> {
+  const padding = "=".repeat((4 - (base64String.length % 4)) % 4);
+  const base64 = (base64String + padding).replace(/-/g, "+").replace(/_/g, "/");
+  const rawData = atob(base64);
+  // Back the array with a concrete ArrayBuffer so it satisfies BufferSource.
+  const outputArray = new Uint8Array(new ArrayBuffer(rawData.length));
+  for (let i = 0; i < rawData.length; i++) {
+    outputArray[i] = rawData.charCodeAt(i);
+  }
+  return outputArray;
+}
+
+function isPushSupported(): boolean {
+  return (
+    typeof window !== "undefined" &&
+    "serviceWorker" in navigator &&
+    "PushManager" in window &&
+    "Notification" in window
+  );
+}
+
+export function usePushNotifications() {
+  const token = useAuthToken();
+  const apiBase = getApiBaseUrl();
+
+  const [permission, setPermission] = useState<PermissionState>("default");
+  const [isSubscribed, setIsSubscribed] = useState(false);
+  const [busy, setBusy] = useState(false);
+
+  // Reflect current permission + subscription state on mount.
+  useEffect(() => {
+    if (!isPushSupported()) {
+      setPermission("unsupported");
+      return;
+    }
+    setPermission(Notification.permission);
+    navigator.serviceWorker.ready
+      .then((reg) => reg.pushManager.getSubscription())
+      .then((sub) => setIsSubscribed(!!sub))
+      .catch(() => setIsSubscribed(false));
+  }, []);
+
+  const authHeaders = useCallback(() => {
+    const headers: Record<string, string> = { "Content-Type": "application/json" };
+    if (token) headers["Authorization"] = `Bearer ${token}`;
+    return headers;
+  }, [token]);
+
+  const subscribe = useCallback(async (): Promise<boolean> => {
+    if (!isPushSupported() || !token) return false;
+    setBusy(true);
+    try {
+      const perm = await Notification.requestPermission();
+      setPermission(perm);
+      if (perm !== "granted") return false;
+
+      // Get the VAPID public key from the backend.
+      const keyRes = await fetch(`${apiBase}/api/notif/v1/push/vapid-public-key/`);
+      const { public_key: publicKey } = await keyRes.json();
+      if (!publicKey) return false;
+
+      const reg = await navigator.serviceWorker.ready;
+      let sub = await reg.pushManager.getSubscription();
+      if (!sub) {
+        sub = await reg.pushManager.subscribe({
+          userVisibleOnly: true,
+          applicationServerKey: urlBase64ToUint8Array(publicKey),
+        });
+      }
+
+      const res = await fetch(`${apiBase}/api/notif/v1/push/subscribe/`, {
+        method: "POST",
+        headers: authHeaders(),
+        body: JSON.stringify(sub.toJSON()),
+      });
+      const ok = res.ok;
+      setIsSubscribed(ok);
+      return ok;
+    } catch (e) {
+      console.error("Push subscribe failed:", e);
+      return false;
+    } finally {
+      setBusy(false);
+    }
+  }, [apiBase, token, authHeaders]);
+
+  const disable = useCallback(async (): Promise<void> => {
+    if (!isPushSupported()) return;
+    setBusy(true);
+    try {
+      const reg = await navigator.serviceWorker.ready;
+      const sub = await reg.pushManager.getSubscription();
+      if (sub) {
+        await fetch(`${apiBase}/api/notif/v1/push/unsubscribe/`, {
+          method: "POST",
+          headers: authHeaders(),
+          body: JSON.stringify({ endpoint: sub.endpoint }),
+        }).catch(() => {});
+        await sub.unsubscribe().catch(() => {});
+      }
+      setIsSubscribed(false);
+    } finally {
+      setBusy(false);
+    }
+  }, [apiBase, authHeaders]);
+
+  return {
+    supported: permission !== "unsupported",
+    permission,
+    isSubscribed,
+    busy,
+    subscribe,
+    disable,
+  };
+}

app/routes/profile.orders.tsx

@@ -27,6 +27,7 @@ import UiProvider from "~/components/UiProvider";
 import { isVideo } from "~/components/MondrianProductList";
 import SellerLogo from "~/components/SellerLogo";
 import { useRootData } from "~/hooks/use-root-data";
+import { useMarkBadgeRead } from "~/hooks/useBadgeCounts";
 // Product Modal Component
 const ProductModal = ({
   product,
@@ -79,6 +80,7 @@ const ProductModal = ({
 
 export default function Orders() {
   const { data, isLoading, isError, error, refetch } = useGetUserOrders();
+  const markBadgeRead = useMarkBadgeRead();
   const [currentData, setCurrentData] = useState<OrderList[]>([]);
   const [activeTab, setActiveTab] = useState(0);
   const [activeFactorId, setActiveFactorId] = useState("");
@@ -86,6 +88,13 @@ export default function Orders() {
   const [showModal, setShowModal] = useState(false);
   const [selectedProduct, setSelectedProduct] =
     useState<OrderItemSummary | null>(null);
+
+  // Visiting the orders page clears the "order status changed" badge.
+  useEffect(() => {
+    markBadgeRead.mutate("order_updates");
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
   // Update currentData when data or activeTab changes
   useEffect(() => {
     if (data) {

app/routes/profile.setting.tsx

@@ -13,6 +13,7 @@ import {
 import { useToast } from "~/hooks/use-toast";
 import { Loader2, Mail, Phone, User } from "lucide-react";
 import { UserProfileUpdateSexEnum } from "src/api/types";
+import { PushSettingToggle } from "~/components/notifications/PushSettingToggle";
 
 export default function Setting() {
   const { data: dataProfile, isFetching: isFetchingProfile } =
@@ -115,6 +116,7 @@ export default function Setting() {
           inputOnChange={() => {}}
           disabled={true}
         />
+        <PushSettingToggle className="border border-WHITE3 rounded-2xl p-4" />
       </div>
       <Divider className={"my-10"} />
       <div className="flex flex-col gap-12 w-full px-5">

app/routes/profile.tsx

@@ -13,10 +13,11 @@ import {
 } from "lucide-react";
 import { useServiceGetProfile } from "~/utils/RequestHandler";
 import { useRootData } from "~/hooks/use-root-data";
+import { useBadgeCounts } from "~/hooks/useBadgeCounts";
 
 const NAV = [
-  { label: "سفارش‌ها", to: "/profile/orders", icon: ShoppingBag },
+  { label: "سفارش‌ها", to: "/profile/orders", icon: ShoppingBag, badgeKey: "order_updates" as const },
-  { label: "پیام‌ها", to: "/profile/threads", icon: MessageCircle },
+  { label: "پیام‌ها", to: "/profile/threads", icon: MessageCircle, badgeKey: "chat" as const },
   { label: "دنبال‌شده‌ها", to: "/profile/following", icon: CircleFadingPlus },
   { label: "ذخیره‌شده‌ها", to: "/profile/bookmarks", icon: BookmarkMinus },
   { label: "ست‌های من", to: "/profile/sets", icon: Layers },
@@ -34,6 +35,7 @@ export default function ProfileLayout() {
   const location = useLocation();
   const { user } = useRootData();
   const { data: profile } = useServiceGetProfile();
+  const { data: badges } = useBadgeCounts();
 
   const isActive = (to: string) =>
     location.pathname === to || location.pathname.startsWith(to + "/");
@@ -56,21 +58,29 @@ export default function ProfileLayout() {
           ) : null}
         </div>
         <nav className="p-2.5 flex flex-col gap-0.5">
-          {NAV.map((n) => (
+          {NAV.map((n) => {
-            <Link
+            const count = n.badgeKey ? badges?.[n.badgeKey] || 0 : 0;
-              key={n.to}
+            return (
-              to={n.to}
+              <Link
-              prefetch="intent"
+                key={n.to}
-              className={`flex items-center gap-3 px-3.5 py-3 rounded-xl text-[14.5px] font-semibold transition-colors ${
+                to={n.to}
-                isActive(n.to)
+                prefetch="intent"
-                  ? "bg-BLACK text-white"
+                className={`flex items-center gap-3 px-3.5 py-3 rounded-xl text-[14.5px] font-semibold transition-colors ${
-                  : "text-BLACK2 hover:bg-WHITE2"
+                  isActive(n.to)
-              }`}
+                    ? "bg-BLACK text-white"
-            >
+                    : "text-BLACK2 hover:bg-WHITE2"
-              <n.icon size={20} />
+                }`}
-              {n.label}
+              >
-            </Link>
+                <n.icon size={20} />
-          ))}
+                {n.label}
+                {count > 0 ? (
+                  <span className="ml-auto min-w-[18px] h-[18px] px-1 rounded-full bg-RED text-white text-[10px] font-bold flex items-center justify-center leading-none">
+                    {count > 99 ? "99+" : count}
+                  </span>
+                ) : null}
+              </Link>
+            );
+          })}
           {user?.access_token ? (
             <Link
               to="/logout"

app/routes/store.$storeId.setting.tsx

@@ -18,6 +18,7 @@ import { useStoreOwnership } from "../hooks/useStoreOwnership";
 import { useState } from "react";
 import { SunMoonToggle } from "~/components/SunMoonToggle";
 import { useRootData } from "~/hooks/use-root-data";
+import { PushSettingToggle } from "~/components/notifications/PushSettingToggle";
 
 // Import the InstagramSyncDrawer component
 import { InstagramSyncDrawer } from "./store.$storeId._index";
@@ -149,7 +150,7 @@ export default function StoreSetting() {
       </h2>
 
       {/* Status + Theme cards */}
-      <div className="lg:grid lg:grid-cols-2 lg:gap-4 lg:mb-6">
+      <div className="lg:grid lg:grid-cols-3 lg:gap-4 lg:mb-6">
         {/* Store Status */}
         <div className="p-4 bg-WHITE border-b border-inner-border lg:border lg:border-WHITE3 lg:rounded-2xl lg:p-6">
           <div className="flex w-full items-center justify-between">
@@ -190,6 +191,9 @@ export default function StoreSetting() {
             <SunMoonToggle theme={initialTheme} />
           </div>
         </div>
+
+        {/* Push notifications */}
+        <PushSettingToggle className="p-4 bg-WHITE border-b border-inner-border lg:border lg:border-WHITE3 lg:rounded-2xl lg:p-6" />
       </div>
 
       {/* Menu Items */}

app/routes/store.$storeId.tsx

@@ -11,6 +11,7 @@ import {
 } from "lucide-react";
 import { useSellerData } from "~/requestHandler/use-seller-hooks";
 import SellerLogo from "~/components/SellerLogo";
+import { useBadgeCounts } from "~/hooks/useBadgeCounts";
 
 /**
  * Desktop layout for the seller dashboard. Renders a sticky admin sidebar
@@ -21,15 +22,26 @@ export default function StoreLayout() {
   const { storeId } = useParams();
   const location = useLocation();
   const { data } = useSellerData(storeId);
+  const { data: badges } = useBadgeCounts();
   const base = `/store/${storeId}`;
 
   const NAV = [
     { label: "فروشگاه", to: base, icon: LayoutGrid, exact: true },
     { label: "محصولات", to: `${base}/products`, icon: Package },
-    { label: "سفارش‌ها", to: `${base}/orders`, icon: ClipboardList },
+    {
+      label: "سفارش‌ها",
+      to: `${base}/orders`,
+      icon: ClipboardList,
+      badge: badges?.seller_orders || 0,
+    },
     { label: "مالی", to: `${base}/financial-dashboard`, icon: Wallet },
     { label: "روش ارسال", to: `${base}/shipping-method`, icon: Truck },
-    { label: "پیام‌ها", to: `${base}/threads`, icon: MessageCircle },
+    {
+      label: "پیام‌ها",
+      to: `${base}/threads`,
+      icon: MessageCircle,
+      badge: badges?.chat || 0,
+    },
     { label: "تنظیمات", to: `${base}/setting`, icon: Settings },
   ];
 
@@ -65,6 +77,11 @@ export default function StoreLayout() {
             >
               <n.icon size={20} />
               {n.label}
+              {n.badge && n.badge > 0 ? (
+                <span className="ml-auto min-w-[18px] h-[18px] px-1 rounded-full bg-RED text-white text-[10px] font-bold flex items-center justify-center leading-none">
+                  {n.badge > 99 ? "99+" : n.badge}
+                </span>
+              ) : null}
             </Link>
           ))}
           <Link

public/sw.js

@@ -142,3 +142,55 @@ self.addEventListener("message", (event) => {
     self.skipWaiting();
   }
 });
+
+// ---- Web Push ----
+// Show a notification when a push arrives. Payload is JSON:
+// { title, body, url, tag, notification_id }
+self.addEventListener("push", (event) => {
+  let data = {};
+  try {
+    data = event.data ? event.data.json() : {};
+  } catch (e) {
+    data = { title: "ویترون", body: event.data ? event.data.text() : "" };
+  }
+
+  const title = data.title || "ویترون";
+  const options = {
+    body: data.body || "",
+    icon: "/icon-192x192.png",
+    badge: "/icon-96x96.png",
+    dir: "rtl",
+    lang: "fa",
+    tag: data.tag || "vitrown",
+    renotify: true,
+    data: { url: data.url || "/", notificationId: data.notification_id },
+  };
+
+  event.waitUntil(self.registration.showNotification(title, options));
+});
+
+// Focus an existing tab (or open a new one) on the target URL when clicked.
+self.addEventListener("notificationclick", (event) => {
+  event.notification.close();
+  const targetUrl = (event.notification.data && event.notification.data.url) || "/";
+
+  event.waitUntil(
+    clients
+      .matchAll({ type: "window", includeUncontrolled: true })
+      .then((clientList) => {
+        for (const client of clientList) {
+          // If a tab is already open, navigate it and focus.
+          if ("focus" in client) {
+            client.focus();
+            if ("navigate" in client) {
+              client.navigate(targetUrl).catch(() => {});
+            }
+            return;
+          }
+        }
+        if (clients.openWindow) {
+          return clients.openWindow(targetUrl);
+        }
+      })
+  );
+});