interface-segregation-1.ts

interface CanBroadcast {
  send(event: Event, user: User)
  trackReads(track: boolean)
}

class EmailBroadcaster implements CanBroadcast {
  send(event: Event, user: User) {
    emailService.send({ to: user.email, subject: event.name })
  }
  trackReads(track: boolean) {
    emailService.setConfig({ trackOpens: track ? "always" : "never" })
  }
}

class PushBroadcaster implements CanBroadcast {
  send(event: Event, user: User) {
    const description = `New event ${event.name} occured!`
    pushService.push({ token: user.pushKey, body: description })
  }
  trackReads(track: boolean) {
    throw new Error("PushBroadcaster does not support tracking reads.");
  }
}