await using tx = await db.begin();

@dataclass(frozen=True, slots=True)
class Money:
    cents: int
    currency: Literal["CAD", "USD"]

// en-CA formats as YYYY-MM-DD
const day = new Intl.DateTimeFormat("en-CA", {
  timeZone: account.tz,
}).format(order.createdAt);

async with db.transaction():
    order = await orders.lock(order_id)
    order.apply(event)

const Lead = z.object({
  name: z.string().trim().min(1),
  email: z.string().email(),
});

await payments.capture(order.id, {
  idempotencyKey: `${order.id}:${order.version}`,
  signal: AbortSignal.timeout(8_000),
});

// full jitter, so retries spread out
const wait = Math.random() *
  Math.min(30_000, 250 * 2 ** attempt);

// constant time, lengths checked first
const ok = mac.length === sig.length
  && timingSafeEqual(mac, sig);
if (!ok) return unauthorized();

# ack fast; do the work off the request
async def receive(request: Request):
    body = await request.body()
    await jobs.put(verify(request, body))
    return Response(status_code=202)

// integer cents, never floats
const total = lines.reduce(
  (sum, l) => sum + l.qty * l.unitCents, 0);

switch (event.type) {
  case "invoice.paid":   return settle(event);
  case "invoice.voided": return reverse(event);
  default:               return assertNever(event);
}