handleData.swift

func handleData() {
    let jsonData: [String: Any]
    let text = String(describing: self.data)
    // JSON serialisation can fail, use do-catch (like try-catch in
    // to cope with possible failuresJava/C)
    do {
        // JSON data is copied into a key/value dictionary
        jsonData = try JSONSerialization.jsonObject(with: self.data, options: [.mutableContainers]) as! [String: Any]
    } catch {
        return debugPrint("Error occurred: \(error.localizedDescription)")
    }

    // Extract the core element main
    guard let main = jsonData["main"] as? [String: Any] else { return }
    // Interpret the JSON elements temp as Double value
    guard let tempKelvin = main["temp"] as? Double else { return }
    // Calculate Kelvin into Celsius
    let tempCelsius = tempKelvin - 273.15

    // Copy the temperature into the corresponding UI label
    self.temperatureLabel.text = String(format: "%.1f °C", tempCelsius) as String

    // Copy description text into the corresponding label of the UI
    self.descriptionLabel.text = description

    // Same for the city name
    guard let name = jsonData["name"] as? String else { return }
    self.cityLabel.text = name

    // next step show location in map
    // handleMap()
}