extract promise

 def get(docId: String, options: js.UndefOr[GetOptions] = GetOptions()) : Future[js.Dynamic] = {
    val promise = Promise[js.Dynamic]
    pouchDBJS.getWithCallback(docId,options,callback = (err : js.UndefOr[js.Dynamic], response :js.UndefOr[js.Dynamic]) => {
      if(js.isUndefined(err) || err == null) promise.success(response.get)
      else promise.failure(PouchDBException(err.get))
    })
    promise.future
  }

  def destroy(options: js.UndefOr[js.Dynamic] = js.undefined): Future[js.Dynamic] = {
    val promise = Promise[js.Dynamic]
    pouchDBJS.destroy((err : js.UndefOr[js.Dynamic], response :js.UndefOr[js.Dynamic]) => {
      if(js.isUndefined(err) || err == null) promise.success(response.get)
      else promise.failure(PouchDBException(err.get))
    })
    promise.future
  }

  def put(doc: js.Object, docId: js.UndefOr[String] = js.undefined, docRev: js.UndefOr[String] = js.undefined, options: js.UndefOr[js.Object] = js.undefined): Future[js.Dynamic] = {
    val promise = Promise[js.Dynamic]
    pouchDBJS.put(doc,docId,docRev,options,(err : js.UndefOr[js.Dynamic], response :js.UndefOr[js.Dynamic]) => {
      if(js.isUndefined(err) || err == null) promise.success(response.get)
      else promise.failure(PouchDBException(err.get))
    })
    promise.future
  }

  def post(doc: js.Object, options: js.UndefOr[js.Object] = js.undefined): Future[js.Dynamic] = {
    val promise = Promise[js.Dynamic]
    pouchDBJS.post(doc,options,(err : js.UndefOr[js.Dynamic], response :js.UndefOr[js.Dynamic]) => {
      if(js.isUndefined(err) || err == null) promise.success(response.get)
      else promise.failure(PouchDBException(err.get))
    })
    promise.future
  }

  def remove(doc: js.Object, options: UndefOr[js.Dynamic] = js.undefined): Future[js.Dynamic] = {
    val promise = Promise[js.Dynamic]
    pouchDBJS.remove(doc,options,(err : js.UndefOr[js.Dynamic], response :js.UndefOr[js.Dynamic]) => {
      if(js.isUndefined(err) || err == null) promise.success(response.get)
      else promise.failure(PouchDBException(err.get))
    })
    promise.future
  }