A series of extensions for future me.

Extensions.swift

import UIKit
import RxSwift
import Moya
import ObjectMapper

extension UIView {
  func loadNib<T: UIView>() -> T {
    guard let view = Bundle.main.loadNibNamed(String(describing: T.self), owner: self, options: [:])?.first as? T else {
      fatalError("Could not init NIB named: \(String(describing: T.self))")
    }
    return view
  }
}

extension UITableView {
  func dequeueReusableCell<T: UITableViewCell>(forIndexPath indexPath: IndexPath) -> T {
    guard let cell = dequeueReusableCell(withIdentifier: String(describing: T.self), for: indexPath) as? T else {
      fatalError("Could not dequeue cell with identifier: \(String(describing: T.self))")
    }
    return cell
  }
}

extension UICollectionView {
  func dequeueReusableCell<T: UICollectionViewCell>(forIndexPath indexPath: IndexPath) -> T {
    guard let cell = dequeueReusableCell(withReuseIdentifier: String(describing: T.self), for: indexPath) as? T else{
      fatalError("Could not dequeue cell with identifier: \(String(describing: T.self))")
    }
    return cell
  }
}

protocol StoryboardIdentifiable {
  static var storyboardIdentifier: String { get }
}

extension StoryboardIdentifiable where Self: UIViewController {
  static var storyboardIdentifier: String {
    return String(describing: self)
  }
}

extension UIViewController : StoryboardIdentifiable { }
extension ObservableType where E == Response {
  func mapNestedArray<T: Mappable>(type: T.Type, in key: String) -> Observable<[T]> {
    return map { response -> Response in
      guard let json = try? response.mapJSON() as? NSDictionary,
        let data = json?[key],
        let newData = try? JSONSerialization.data(withJSONObject: data, options: JSONSerialization.WritingOptions.prettyPrinted) else {
          return response
      }
      let newResponse = Response(statusCode: response.statusCode, data: newData, response: response.response)
      return newResponse
      }
      .mapArray(type)
  }
}

extension PrimitiveSequence where E == Response {
  func mapNestedArray<T: Mappable>(type: T.Type, in key: String) -> Observable<[T]> {
    return asObservable().map { response -> Response in
      guard let json = try? response.mapJSON() as? NSDictionary,
        let data = json?[key],
        let newData = try? JSONSerialization.data(withJSONObject: data, options: JSONSerialization.WritingOptions.prettyPrinted) else {
          return response
      }
      let newResponse = Response(statusCode: response.statusCode, data: newData, response: response.response)
      return newResponse
      }
      .mapArray(type)
  }
}