Consider supporting Async/Await ? about then HOT 7 CLOSED

// Classic
getPhotos()
  .then(fetchPhotosInfo)
  .then(syncPhotos)

//Async/Await
let photos = try! await(getPhotos())
try! await(fetchPhotosInfo(photos))
try! await(syncPhotos())

//Async Await + error Handling
do {
  let user = try await(getPhotos()))
  try await(fetchPhotosInfo(photos)) 
  try await(syncPhotos())
} catch {
  print(error)
}

typealias Async<T> = Promise<T>
typealias AsyncTask = Async<Void>

func async<T>(block:@escaping () throws -> T) -> Async<T> {
    return Promise { resolve, reject in
        do {
            let t = try block()
            resolve(t)
        } catch {
            reject(error)
        }
    }
}

func await<T>(_ promise:Promise<T>) throws -> T {
    var result: T?
    var error: Error?
    let group = DispatchGroup()
    group.enter()
    promise.then { t in
        result = t
        group.leave()
    }.onError { e in
        error = e
        group.leave()
    }
    group.wait()
    if let e = error {
        throw e
    }
    return result!
}

func getPhotos() -> Async<[Photo]> {
    return async {
        // Do something
        return [Photo(), Photo(), Photo()]
    }
}

// then
let photos = try! await(getPhotos())

func async<T>(block:@escaping () throws -> T) -> Async<T> {
    return Promise { resolve, reject in
        DispatchQueue(label: "testqueue", attributes: .concurrent).async {
            do {
                let t = try block()
                resolve(t)
            } catch {
                reject(error)
            }
        }
    }
}