/**
 * @license
 * Copyright 2017 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
export interface Resolver<R> {
    (value?: R | Promise<R>): void;
}
export interface Rejecter {
    (reason?: Error): void;
}
export interface CancelablePromise<T> {
    then<TResult1 = T, TResult2 = never>(onfulfilled?: ((value: T) => TResult1 | PromiseLike<TResult1>) | undefined | null, onrejected?: // eslint-disable-next-line @typescript-eslint/no-explicit-any
    ((reason: any) => TResult2 | PromiseLike<TResult2>) | undefined | null): Promise<TResult1 | TResult2>;
    catch<TResult = never>(onrejected?: // eslint-disable-next-line @typescript-eslint/no-explicit-any
    ((reason: any) => TResult | PromiseLike<TResult>) | undefined | null): Promise<T | TResult>;
    cancel(): void;
}
export declare class Deferred<R> {
    promise: Promise<R>;
    resolve: Resolver<R>;
    reject: Rejecter;
    constructor();
}
/**
 * Takes an array of values and a function from a value to a Promise. The function is run on each
 * value sequentially, waiting for the previous promise to resolve before starting the next one.
 * The returned promise resolves once the function has been run on all values.
 */
export declare function sequence<T>(values: T[], fn: (value: T) => Promise<void>): Promise<void>;
