feature: poll and render open orders

app.js

@@ -0,0 +1,37 @@
+// Kitchen display: poll open orders and render them oldest-first so the
+// pass works the tickets in the order they landed. Kiosk mode, no input.
+const POLL_MS = 2000;
+const root = document.getElementById("orders");
+
+function ageClass(placedAt) {
+  const mins = (Date.now() - new Date(placedAt).getTime()) / 60000;
+  if (mins > 8) return "ticket late";
+  if (mins > 4) return "ticket warn";
+  return "ticket";
+}
+
+function render(orders) {
+  orders.sort((a, b) => new Date(a.placed_at) - new Date(b.placed_at));
+  root.innerHTML = "";
+  for (const o of orders) {
+    const el = document.createElement("div");
+    el.className = ageClass(o.placed_at);
+    el.innerHTML =
+      `<h2>#${o.number}</h2>` +
+      o.items.map((i) => `<span>${i.qty}x ${i.name}</span>`).join("");
+    root.appendChild(el);
+  }
+}
+
+async function tick() {
+  try {
+    const res = await fetch("/api/orders?state=open", { cache: "no-store" });
+    if (res.ok) render(await res.json());
+  } catch (err) {
+    // A blip on the pass network is not worth clearing the board over.
+    console.warn("orders poll failed", err);
+  }
+}
+
+tick();
+setInterval(tick, POLL_MS);