UIControlEventPublisher.swift

UIControlEventPublisher.swift

class ActionTarget {
    let handler: () -> Void

    init(handler: @escaping () -> Void) {
        self.handler = handler
    }

    @IBAction func handle() {
        handler()
    }
}

struct AnySubscription: Subscription {
    func request(_ demand: Subscribers.Demand) {
        _request(demand)
    }

    func cancel() {
        _cancel()
    }

    var combineIdentifier: CombineIdentifier = CombineIdentifier(NSUUID())

    let _request: (Subscribers.Demand) -> Void
    let _cancel: () -> Void
}

extension UIControl {
    func eventPublisher(for event: UIControl.Event) -> AnyPublisher<UIControl, Never> {
        return AnyPublisher { subscriber in
            var target: ActionTarget?
            subscriber.receive(subscription: AnySubscription(_request: { _ in }, _cancel: {
                target = nil
            }))
            target = ActionTarget {
                _ = subscriber.receive(self)
            }

            self.addTarget(target, action: #selector(ActionTarget.handle), for: event)
        }
    }
}