Push Notifications: Examples & Troubleshooting

Examples

Notify when something is created (DB trigger)

New repair request: tell the landlord

addDbTrigger("set", ["repairs", "$id"], (context) => {
  if (context.dataBefore !== undefined) return;          // only brand-new requests
  const repair = context.dataAfter;
  const landlord = get(["buildings", repair.building, "owner"]).data;
  sendPush(["users", landlord, "pushTokens"], {
    title: `New repair: ${repair.flat}`,
    body: repair.summary,
    url: `/repairs/${context.path[1]}`,
    tag: `repair-${context.path[1]}`
  });
});

A whole team

Team run moved: tell everyone on the team

addDbTrigger("update", ["teams", "$teamId", "nextRun"], (context) => {
  const teamId = context.path[1];
  sendPush(["teams", teamId, "pushTokens"], {
    title: "Saturday's run has changed",
    body: `Now ${context.dataAfter.time} at ${context.dataAfter.place}`,
    url: `/teams/${teamId}`,
    topic: "next-run"                                  // a newer change replaces an undelivered older one
  });
});

Reminders at a set time

There's no built-in scheduler. Store the time on the record and check every minute. Mark each reminder as sent before sending, so a restart can never send it twice.

Booking reminders, 24 hours ahead

setInterval(() => {
  const soon = Date.now() + 24 * 60 * 60 * 1000;
  const due = query({ path: ["bookings"], query: `child.at <= ${soon} && !child.reminded` }).data || {};
  for (const [id, b] of Object.entries(due)) {
    update(["bookings", id], { reminded: true });         // mark first: never send twice
    sendPush(["users", b.uid, "pushTokens"], {
      title: "Appointment tomorrow",
      body: `${new Date(b.at).toLocaleTimeString([], { hour: "2-digit", minute: "2-digit" })} with ${b.groomer}`,
      url: `/bookings/${id}`
    });
  }
}, 60 * 1000);

Staff notify a customer (callable)

"Your order is ready" button for staff

addCallable("orderReady", async (data, admin) => {
  if (!admin.claims?.staff) return { status: "Failed", message: "Staff only" };
  const order = get(["orders", data.orderId]).data;
  if (!order) return { status: "Failed", message: "No such order" };
  update(["orders", data.orderId], { status: "ready" });
  // The server picks the target from the order, never from the caller.
  return sendPush(["users", order.customerUid, "pushTokens"], { title: "Your order is ready", url: `/orders/${data.orderId}` });
});

Everyone, or fans without accounts

New show announced

// Browser, no sign-in (uses rule 3 above):
await client.push.enable(["fans"]);

// Server: every fan device, plus every signed-in user
addDbTrigger("set", ["shows", "$id"], (context) => {
  if (context.dataBefore !== undefined) return;
  sendPush([["fans"], ["users", "$uid", "pushTokens"]], {
    title: "New show announced",
    body: context.dataAfter.venue,
    url: "/shows"
  });
});

Troubleshooting

Symptom	Likely cause	Fix
The button does nothing on iPhone	The page is open in Safari, not installed.	Show the `"install-first"` hint: Share, then Add to Home Screen.
`enable()` returns `"not-saved"`	Your rules refused the write, often because the user isn't signed in.	Check the write rule for that path.
`sendPush` returns `sent: 0`	The target points one level too high, for example `["users"]`.	Point at the map of devices itself, or use a wildcard: `["users", "$uid", "pushTokens"]`.
`status()` is `"unsupported"` on a phone	The link was opened inside Facebook or Instagram.	Ask the user to open the page in Safari or Chrome.
`sent: 1` but nothing appears	Notifications are off for the app in the phone's settings, or Focus mode is on.	Check Settings, Notifications, then your app.
Everyone had to turn notifications on again	The keys changed (a different or removed `configurePush` pair, or `_nukebase/pushKeys` replaced or removed), `/sw.js` moved, or the app's address changed.	Keep all three stable. A lost key pair can only be recovered from a backup.
`sendPush` rejects "payload too large"	Over 3 KB of JSON.	Send a short message plus a `url`.