add expiry push notifications

static/push-sw.js

@@ -0,0 +1,33 @@
+/* global self */
+self.addEventListener("push", (event) => {
+  let message = {
+    title: "HotFridge",
+    body: "You have food expiring soon.",
+    url: "/app/list",
+  };
+  try {
+    message = { ...message, ...JSON.parse(event.data?.text() ?? "{}") };
+  } catch {
+    // Keep the generic notification when a payload cannot be decoded.
+  }
+
+  event.waitUntil(
+    self.registration.showNotification(message.title, {
+      body: message.body,
+      tag: "near-expiry",
+      renotify: true,
+      data: { url: message.url },
+    }),
+  );
+});
+
+self.addEventListener("notificationclick", (event) => {
+  event.notification.close();
+  const url = event.notification.data?.url ?? "/app/list";
+  event.waitUntil(
+    self.clients.matchAll({ type: "window", includeUncontrolled: true }).then((clients) => {
+      const existing = clients.find((client) => new URL(client.url).pathname === url);
+      return existing ? existing.focus() : self.clients.openWindow(url);
+    }),
+  );
+});