vialyx

[
  "https://images.pexels.com/photos/67636/rose-blue-flower-rose-blooms-67636.jpeg",
  "https://cdn5.img.ria.ru/images/148839/96/1488399690.jpg",
  "https://i.pinimg.com/564x/36/a1/bd/36a1bdea08a849595fd00ae49d6e7c87.jpg",
  "https://developer.apple.com/swift/images/swift-og.png",
  "https://cdnimg.rg.ru/img/content/128/35/27/Geofiziki_predupredili_ob_izverzhenii_supervulkana_d_850.jpg",
  "https://images.pexels.com/photos/67636/rose-blue-flower-rose-blooms-67636.jpeg",
  "https://cdn5.img.ria.ru/images/148839/96/1488399690.jpg",
  "https://i.pinimg.com/564x/36/a1/bd/36a1bdea08a849595fd00ae49d6e7c87.jpg",
  "https://developer.apple.com/swift/images/swift-og.png",

vialyx

let group = DispatchGroup()

let workItemFirst = DispatchWorkItem {
    print("exec 1st WI")
    // 1
    group.leave()
}

let workItemSecond = DispatchWorkItem {
    print("exec 2nd WI")

vialyx

let workItemFirst = DispatchWorkItem {
    print("exec 1st WI")
    // 2
}

let workItemSecond = DispatchWorkItem {
    print("exec 1st WI")
    // Not called
}

vialyx

let background = DispatchQueue.init(label: "background", qos: .background)
// Work takes significant time, such as minutes or hours.

let utility = DispatchQueue.init(label: "utility", qos: .utility)
// Work takes a few seconds to a few minutes.

let `default` = DispatchQueue.init(label: "default", qos: .default)
// The priority level of this QoS falls between user-initiated and utility. This QoS is not intended to be used by developers to classify work. Work that has no QoS information assigned is treated as default, and the GCD global queue runs at this level.

let userInitiated = DispatchQueue.init(label: "userInitiated", qos: .userInitiated)

vialyx

DispatchQueue.init(label: "defaultQos").async {
    print("async defaultQos exec")
    // 2
    DispatchQueue.main.async {
        print("async main exec")
        // 3
    }
}

print("sync main exec")

vialyx

let concurent = DispatchQueue.init(label: "defaultQos", attributes: .concurrent)

concurent.sync {
    print("sync defaultQos exec")
    // 1
}
concurent.sync {
    print("sync defaultQos exec")
    // 2
}

vialyx

DispatchQueue.init(label: "defaultQos").sync {
    print("sync defaultQos exec")
    // 1
}

DispatchQueue.init(label: "defaultQos").async {
    print("async defaultQos exec")
    // 3
}

vialyx

<JsonCoddableUrlSession.ViewController: 0x7fc17051ac40> retrive flights: [JsonCoddableUrlSession.FlightData(Airline: "AEROFLOT", Flight: "SU1834", ActualTime: ""), JsonCoddableUrlSession.FlightData(Airline: "AEROFLOT", Flight: "SU1838", ActualTime: ""), JsonCoddableUrlSession.FlightData(Airline: "BELAVIA", Flight: "B2776", ActualTime: ""), JsonCoddableUrlSession.FlightData(Airline: "BELAVIA", Flight: "B2936", ActualTime: ""), JsonCoddableUrlSession.FlightData(Airline: "BELAVIA", Flight: "B2736", ActualTime: ""), JsonCoddableUrlSession.FlightData(Airline: "BELAVIA", Flight: "B2848", ActualTime: ""), JsonCoddableUrlSession.FlightData(Airline: "BELAVIA", Flight: "B2944", ActualTime: ""), JsonCoddableUrlSession.FlightData(Airline: "BELAVIA", Flight: "B2954", ActualTime: "")

vialyx

      ...
      repository.getFlights(.remote) { (result) in
            switch result {
      ...

vialyx

      ...
      let repository = Repository(apiClient: APIClient(), database: Database())
      ...