Swift 4 introduces a new Codable protocol that lets you serialize and deserialize custom data types without writing any special code and without having to worry about losing your value types. 
  
Awesome, isn't it? And this library helps you write less code! It's an extension for Alamofire that converts JSON data into Decodable object.
Useful Resources:
- Encoding and Decoding Custom Types - Article by Apple
 - Using JSON with Custom Types - Swift Playground
 - Also there is a special session from 
WWDC2017that covers this new feature - What's New in Foundation 
Usage
Let's decode a simple json file:
{
    "result": {
        "libraries": [
            {
                "name": "Alamofire",
                "stars": 23857,
                "url": "https://github.com/Alamofire/Alamofire",
                "random_date_commit": 1489276800
            },
            {
                "name": "RxSwift",
                "stars": 9600,
                "url": "https://github.com/ReactiveX/RxSwift",
                "random_date_commit": 1494547200
            }	
        ]
    }
}
 
with the following Swift model:
private struct Repo: Decodable {
    let name: String
    let stars: Int
    let url: URL
    let randomDateCommit: Date
    
    private enum CodingKeys: String, CodingKey {
        case name
        case stars
        case url
        case randomDateCommit = "random_date_commit"
    }
} 
There is a similar method to responseData, responseJSON - responseDecodableObject:
func responseDecodableObject<T: Decodable>(queue: DispatchQueue? = nil, keyPath: String? = nil, decoder: JSONDecoder = JSONDecoder(), completionHandler: @escaping (AFDataResponse<T>) -> Void) 
queue- The queue on which the completion handler is dispatched.keyPath- The keyPath where object decoding should be performed.decoder- The decoder that performs the decoding of JSON into semanticDecodabletype.
let url = URL(string: "https://raw.githubusercontent.com/otbivnoe/CodableAlamofire/master/keypathArray.json")!
let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .secondsSince1970 // It is necessary for correct decoding. Timestamp -> Date.
AF.request(url).responseDecodableObject(keyPath: "result.libraries", decoder: decoder) { (response: AFDataResponse<[Repo]>) in
    let repo = response.value
    print(repo)
} 
Note:
- For array: 
DataResponse<[Repo]> - For single object: 
DataResponse<Repo> 
Requirements
- Swift 4+
 - Xcode 9+
 
Installation 
   🔥 
  
 
CocoaPods
CocoaPods is a dependency manager for Swift and Objective-C Cocoa projects. It has over eighteen thousand libraries and can help you scale your projects elegantly. You can install it with the following command:
$ sudo gem install cocoapods 
To integrate CodableAlamofire, simply add the following line to your Podfile:
target 'Test' do
  use_frameworks!
  pod 'CodableAlamofire'
  
end 
Carthage
Carthage is a decentralized dependency manager that builds your dependencies and provides you with binary frameworks.
You can install Carthage with Homebrew using the following command:
$ brew update
$ brew install carthage 
To integrate CodableAlamofire into your Xcode project using Carthage, specify it in your Cartfile:
github "Otbivnoe/CodableAlamofire"
 
Run carthage update to build the framework and drag the built CodableAlamofire.framework into your Xcode project.
