feat: offline content

components/pwa/sw-register.tsx

@@ -0,0 +1,44 @@
+"use client";
+
+/**
+ * ServiceWorkerRegistrar — registers the app's service worker for everyone on
+ * load (not just when a user opts into push). The same `/sw.js` now also
+ * powers the Save-offline feature (caching page HTML + assets), so it must be
+ * active regardless of push. The `?bff=` query matches the push registration
+ * exactly (see lib/push.ts) so there's a single registration / scope, and push
+ * subscription management keeps working.
+ */
+
+import { useEffect } from "react";
+import { precacheOfflineLibrary } from "@/lib/offline";
+
+const BFF_BASE = process.env.NEXT_PUBLIC_BFF_URL || "http://localhost:8080";
+
+export function ServiceWorkerRegistrar() {
+  useEffect(() => {
+    if (typeof navigator === "undefined" || !("serviceWorker" in navigator)) {
+      return;
+    }
+    const register = () => {
+      navigator.serviceWorker
+        .register(`/sw.js?bff=${encodeURIComponent(BFF_BASE)}`)
+        .then(() => {
+          // Precache the offline library so it works as the SW navigation
+          // fallback even if the user never opens it online.
+          void precacheOfflineLibrary();
+        })
+        .catch(() => {
+          /* registration is best-effort; the app works online without it */
+        });
+    };
+    // Defer past first paint so it never competes with hydration.
+    if (document.readyState === "complete") {
+      register();
+      return;
+    }
+    window.addEventListener("load", register, { once: true });
+    return () => window.removeEventListener("load", register);
+  }, []);
+
+  return null;
+}