SampleApp
├── Model
│    └── HotpepperAPI.swift
├── ViewModel
│    └── HotpepperAPIViewModel.swift
├── View
│    └── ViewController.swift
├── AppDelegate.swift
└── Main.storyboard

import UIKit
import GoogleMaps

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

  var window: UIWindow?

  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.

    if let path = Bundle.main.path(forResource: "key", ofType: "plist") {
      if let dic = NSDictionary(contentsOfFile: path) as? [String: Any] {
        if let apiKey = dic["googleMapsApiKey"] as? String {
          GMSServices.provideAPIKey(apiKey)
        }
      }
    }

    return true
  }
  ...
}

// HotpepperAPI.swift
import Foundation
import CoreLocation
import Alamofire
import SwiftyJSON

/**
 ホットペッパーAPI
 */
class HotpepperAPI {
  /// API Key
  private var apiKey: String = String()
  /// ホットペッパーAPIのベースURL
  private let baseURL: String = "https://webservice.recruit.co.jp/hotpepper/gourmet/v1/"

  /// 初期化処理
  init() {
    if let path = Bundle.main.path(forResource: "key", ofType: "plist") {
      if let dic = NSDictionary(contentsOfFile: path) as? [String: Any] {
        if let apiKey = dic["hotpepperApiKey"] as? String {
          self.apiKey = apiKey
        }
      }
    }
  }

  /**
   ホットペッパーグルメサーチAPI

   - parameter coordinate: 位置
   - parameter completion: レストラン情報を返却するcallback
   */
  func searchRestaurant(coordinate: CLLocationCoordinate2D, completion: @escaping ((JSON) -> Void)) {
    let parameters = ["key": self.apiKey, "format": "json", "lat": coordinate.latitude, "lng": coordinate.longitude, "range": 2] as [String : Any]
    Alamofire.request(baseURL, method: .get, parameters: parameters, encoding: URLEncoding.default, headers: nil).responseJSON { response in
      let json = JSON(response.result.value as Any)
      let result = json["results"]["shop"]

      completion(result)
    }
  }
}

// HotpepperAPIViewModel.swift
import Foundation
import ReactiveKit
import Bond
import SwiftyJSON
import CoreLocation

/// 通信の各状態をEnumで表現
enum RequestState {
  case none
  case requesting
  case finish
  case error
}

/// HotpepperAPIのViewModelクラス
final class HotpepperAPIViewModel {

  var items: ObservableArray<JSON> = ObservableArray([])
  let requestState = Observable<RequestState>(.none)
  let hotpepperAPI = HotpepperAPI.init()

  var finishSearchRestaurant: Signal<[JSON]?, NoError> {
    return self.requestState.map({ (requestState) -> [JSON]? in
      if requestState == .finish {
        return self.items.array
      }
      return nil
    })
  }

  func searchRestaurant(coordinate: CLLocationCoordinate2D) {
    self.requestState.next(RequestState.requesting)
    hotpepperAPI.searchRestaurant(coordinate: coordinate, completion: { (result) in
      guard let resultArray = result.array else {
        return
      }
      self.items = ObservableArray(resultArray)
      self.requestState.next(RequestState.finish)
    })
  }
}

// ViewController.swift
import UIKit
import GoogleMaps
import SwiftyJSON
import RealmSwift

class ViewController: UIViewController {
  /// マップビュー
  @IBOutlet weak var mapView: GMSMapView!
  /// 検索ボタン
  @IBOutlet weak var searchButton: UIButton!
  /// 現在地
  internal var currentLocation: CLLocationCoordinate2D?
  /// ViewModel
  internal var hotpepperAPIVM = HotpepperAPIViewModel()

  override func viewDidLoad() {
    super.viewDidLoad()

    // データバインディング機構の設定処理
    self.setUpBind()
  }

  ...

  private func setUpBond() {
    // 検索ボタンをタップ(.touchUpInside)したときに呼び出される処理
    _ = self.searchButton.reactive.tap.observeNext { _ in
      self.hotpepperAPIVM.searchRestaurant(coordinate: self.currentLocation!)
    }
    // finishSearchRestaurantから値が返却されるときに呼び出される処理
    _ = self.hotpepperAPIVM.finishSearchRestaurant.ignoreNil().observeNext(with: { (searchShops) in
      for searchShop in searchShops {
        // Google Mapへのマッピング処理
        // 省略
      }
    })
  }
}