What is the Saga pattern, and how does it manage distributed transactions across multiple Node.js microservices?

Because distributed systems typically can't use a single ACID database transaction spanning multiple services, the Saga pattern manages a multi-step business process as a sequence of local transactions, each in its own service, with a corresponding compensating action defined for each step to undo it if a later step fails -- implemented either as choreography (each service listens for events and reacts, fully decentralized) or orchestration (a central coordinator explicitly calls each step and triggers compensations on failure).

// Orchestration-style saga (simplified)
async function bookTripSaga(trip) {
  const flight = await bookFlight(trip);
  try {
    const hotel = await bookHotel(trip);
    try {
      return await bookCar(trip);
    } catch (err) { await cancelHotel(hotel); throw err; }
  } catch (err) { await cancelFlight(flight); throw err; }
}