1// Copyright (C) 2018 The Android Open Source Project
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15// Promise wrapper with exposed resolve and reject callbacks.
16export interface Deferred<T> extends Promise<T> {
17  readonly resolve: (value?: T|PromiseLike<T>) => void;
18  readonly reject: (reason?: any) => void;
19}
20
21// Create a promise with exposed resolve and reject callbacks.
22export function defer<T>(): Deferred<T> {
23  let resolve = null as any;
24  let reject = null as any;
25  const p = new Promise((res, rej) => [resolve, reject] = [res, rej]);
26  return Object.assign(p, {resolve, reject}) as any;
27}
28