notfication-center-subscription-exp-4

import UIKit
import Combine

extension Notification.Name {
    static let newEvent = Notification.Name("new_event")
}

struct Event {
    let title: String
    let scheduledOn: Date
}

let eventPublisher = NotificationCenter.Publisher(center: .default, name: .newEvent, object: nil)
    .map { (notification) -> String? in
        return (notification.object as? Event)?.title ?? ""
    }

let theEventTitleLabel = UILabel()

let newEventLabelSubscriber = Subscribers.Assign(object: theEventTitleLabel, keyPath: \.text)
eventPublisher.subscribe(newEventLabelSubscriber)

let event = Event(title: "Introduction to Combine Framework", scheduledOn: Date())
NotificationCenter.default.post(name: .newEvent, object: event)
print("Recent event notified is: \(theEventTitleLabel.text!)")