Check Device Model in Swift

CurrentDevice.swift

public extension UIDevice {
    
    var modelName: String {
        #if (arch(i386) || arch(x86_64)) && os(iOS)
            let DEVICE_IS_SIMULATOR = true
        #else
            let DEVICE_IS_SIMULATOR = false
        #endif
        
        var machineString : String = ""
        
        if DEVICE_IS_SIMULATOR == true
        {
            
            if let dir = NSProcessInfo().environment["SIMULATOR_MODEL_IDENTIFIER"] {
                machineString = dir
            }
        }
        else {
            var systemInfo = utsname()
            uname(&systemInfo)
            let machineMirror = Mirror(reflecting: systemInfo.machine)
            machineString = machineMirror.children.reduce("") { identifier, element in
                guard let value = element.value as? Int8 where value != 0 else { return identifier }
                return identifier + String(UnicodeScalar(UInt8(value)))
            }
        }
        switch machineString {
        case "iPod5,1":                                 return "iPod Touch 5"
        case "iPod7,1":                                 return "iPod Touch 6"
        case "iPhone3,1", "iPhone3,2", "iPhone3,3":     return "iPhone 4"
        case "iPhone4,1":                               return "iPhone 4s"
        case "iPhone5,1", "iPhone5,2":                  return "iPhone 5"
        case "iPhone5,3", "iPhone5,4":                  return "iPhone 5c"
        case "iPhone6,1", "iPhone6,2":                  return "iPhone 5s"
        case "iPhone7,2":                               return "iPhone 6"
        case "iPhone7,1":                               return "iPhone 6 Plus"
        case "iPhone8,1":                               return "iPhone 6s"
        case "iPhone8,2":                               return "iPhone 6s Plus"
        case "iPad2,1", "iPad2,2", "iPad2,3", "iPad2,4":return "iPad 2"
        case "iPad3,1", "iPad3,2", "iPad3,3":           return "iPad 3"
        case "iPad3,4", "iPad3,5", "iPad3,6":           return "iPad 4"
        case "iPad4,1", "iPad4,2", "iPad4,3":           return "iPad Air"
        case "iPad5,3", "iPad5,4":                      return "iPad Air 2"
        case "iPad2,5", "iPad2,6", "iPad2,7":           return "iPad Mini"
        case "iPad4,4", "iPad4,5", "iPad4,6":           return "iPad Mini 2"
        case "iPad4,7", "iPad4,8", "iPad4,9":           return "iPad Mini 3"
        case "iPad5,1", "iPad5,2":                      return "iPad Mini 4"
        case "iPad6,7", "iPad6,8":                      return "iPad Pro"
        case "AppleTV5,3":                              return "Apple TV"
        default:                                        return machineString
        }
    }
}

//Usage
func isiPhone4Screen() -> Bool {
    return UIDevice.currentDevice().modelName.lowercaseString.rangeOfString("iphone 4") != nil
}