What is a Facade pattern, and how might it be used to simplify a Node.js application's interaction with several third-party SDKs?

A Facade provides a single, simplified interface over a more complex subsystem of classes or libraries -- rather than every part of an application directly importing and configuring multiple third-party SDKs (payment, email, SMS, analytics) with their own inconsistent APIs, a Facade wraps them behind one consistent internal interface, isolating the rest of the codebase from those libraries' specific quirks and making it easier to later swap out or upgrade an underlying SDK.

class NotificationFacade {
  constructor() { this.email = new SendGridClient(); this.sms = new TwilioClient(); }
  async notifyUser(user, message) {
    if (user.prefersEmail) return this.email.send(user.email, message);
    return this.sms.send(user.phone, message);
  }
}

// Rest of the app only ever calls this simple interface
await notificationFacade.notifyUser(user, 'Your order has shipped');