RxAlamofire usage with Codable protocol for object mapping. Inspired by: https://gist.github.com/kciter/e6f13119cbf8ad0963a68a5ebc421069

RxAlamofire+Codable.swift

// Model
import Foundation

class Post: Codable {
	var id = 0
	var userId = 0
	var title = ""
	var body = ""
}

// ObservableType Extension
import RxSwift

extension ObservableType {
	
	public func mapObject<T: Codable>(type: T.Type) -> Observable<T> {
		return flatMap { data -> Observable<T> in
			let responseTuple = data as? (HTTPURLResponse, Data)

			guard let jsonData = responseTuple?.1 else {
				throw NSError(
					domain: "",
					code: -1,
					userInfo: [NSLocalizedDescriptionKey: "Could not decode object"]
				)
			}
			
			let decoder = JSONDecoder()
			let object = try decoder.decode(T.self, from: jsonData)
			
			return Observable.just(object)
		}
	}
	
	public func mapArray<T: Codable>(type: T.Type) -> Observable<[T]> {
		return flatMap { data -> Observable<[T]> in
			let responseTuple = data as? (HTTPURLResponse, Data)
			
			guard let jsonData = responseTuple?.1 else {
				throw NSError(
					domain: "",
					code: -1,
					userInfo: [NSLocalizedDescriptionKey: "Could not decode object"]
				)
			}
			
			let decoder = JSONDecoder()
			let objects = try decoder.decode([T].self, from: jsonData)
			
			return Observable.just(objects)
		}
	}
}

// View controller
import UIKit
import RxSwift
import RxAlamofire

class ViewController: UIViewController {

	let disposeBag = DisposeBag()
	
	override func viewDidLoad() {
		super.viewDidLoad()

		RxAlamofire.requestData(.get, "https://jsonplaceholder.typicode.com/posts")
			.mapArray(type: Post.self)
			.subscribe(onNext: { posts in
				_ = posts.map { print($0.title) }
			})
			.disposed(by: disposeBag)
	}
}