cancel-publisher.swift

extension Publisher {
  func cancellable<Id: Hashable>(id: Id) -> AnyPublisher<Output, Failure> {
    return Deferred { () -> PassthroughSubject<Output, Failure> in
      cancellables[id]?.cancel()
      let subject = PassthroughSubject<Output, Failure>()
      cancellables[id] = self.subscribe(subject)
      return subject
    }
    .eraseToAnyPublisher()
  }
}

private var cancellables: [AnyHashable: AnyCancellable] = [:]