NSURLSession POST request - Swift 4.2

NSURLSession POST request

        guard let urlEncodedString = (AppConstants.URL.sendDeviceTokekn).addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed) else {
            return
        }
        let url = URL(string: urlEncodedString)!
        let urlRequest = NSMutableURLRequest(url: url, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 60.0)
        urlRequest.setValue("Application/json", forHTTPHeaderField: "Content-Type")
        urlRequest.setValue("Application/json", forHTTPHeaderField: "Accept")
        urlRequest.httpMethod = "POST"
        
        let params: [String : Any] = ["txDeviceToken":token, "tDeviceOs":2]
        guard let httpBody = try? JSONSerialization.data(withJSONObject: params, options: []) else {
            return
        }
        urlRequest.httpBody = httpBody

        let task = URLSession.shared.dataTask(with: urlRequest as URLRequest) { (data, response, error) in
            guard let data = data, error == nil else {
                print("error=\(error ?? "Could not save Device Token" as! Error)")
                return
            }
            do {
                let tokenResponse = try JSONDecoder().decode(TokenResponse.self, from: data)
                print(tokenResponse.message)
            } catch {
                print("json error: \(error)")
            }
        }
        task.resume()

TokenResponse.swift

import Foundation
struct TokenResponse: Codable {
    var message:String    
}