flatmap usage

flatmap usage.swift

            let sdevices = devices.flatMap({ (device: Device) -> String in
                return "\(device.brand)-\(device.hostname)-\(device.ipAddress)-\(device.macAddress)\n"
            }).flatMap({$0}).joined()
            
            DispatchQueue.main.async {
                JDAlert(title: "Found \(devices.count) Device(s).", message: sdevices, preferredStyle: .alert)
                    .addAction(title: "OK", style: .default) { _ in }
                    .show()
            }