Blog: ObservableObjects and Protocols - Protocol usage in UIKit

blog--observableobject+protocols--protocol-in-uikit.swift

// Copyright 2021 Expedia, Inc.
// SPDX-License-Identifier: Apache-2.0

import Combine
import UIKit

class DemoController: UIViewController {
    
    private let pricing: PriceRequesting
  
    init(pricing: PriceRequesting) {
      self.pricing = pricing
      // ...
    }
  
    // ...
  
    private func subscribe() {
        // pricing.$price.sink { newPrice in
        pricing.pricePublisher.sink { newPrice in
            guard let price = newPrice else {
                self.priceLabel.text = "Price not available"
                return
            }
            self.priceLabel.text = "\(price.amount) \(price.description)"
        }
        .store(in: &subscriptions)
    }
}