//
//  Await.swift
//  then
//
//  Created by Sacha Durand Saint Omer on 13/03/2017.
//  Copyright © 2017 s4cha. All rights reserved.
//

import Foundation
import Dispatch

@discardableResult public 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
}