Combine walkthrough

underdogdev_combine.swift

import Foundation
import Combine
import UIKit
import PlaygroundSupport

struct Image: Decodable {
    let url: String
}

let stackView = UIStackView(frame: CGRect(x: 0, y: 0, width: 200, height: 600))
stackView.axis = .vertical

let images = URLSession.shared.dataTaskPublisher(for: URL(string: "https://atrinh.com/dev/images.json")!)
    .map(\.data)
    .decode(type: [Image].self, decoder: JSONDecoder())
    .flatMap { $0.publisher }
    .compactMap { URL(string: $0.url) }
    .flatMap { url in
        return URLSession.shared.dataTaskPublisher(for: url)
            .mapError { $0 as Error }
            .map { response in
                UIImage(data: response.data)
            }
    }
    .receive(on: DispatchQueue.main)
    .sink(receiveCompletion: { _ in },
          receiveValue: { image in
        let imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
        imageView.image = image
        stackView.addArrangedSubview(imageView)
    })

PlaygroundPage.current.liveView = stackView