/**
 * @license
 * Copyright 2019 Google LLC
 * SPDX-License-Identifier: BSD-3-Clause
 */
/// <reference types="node" />
/// <reference types="node" />
import { ExecFileOptions } from 'child_process';
/** Return whether the given string is a valid HTTP URL. */
export declare function isHttpUrl(str: string): boolean;
export declare function fileKind(path: string): Promise<'file' | 'dir' | undefined>;
export declare function runNpm(args: string[], options?: ExecFileOptions): Promise<string | Buffer>;
/**
 * Promisified version of setTimeout.
 */
export declare const wait: (ms: number) => Promise<unknown>;
/**
 * A function that should never be called. But if it somehow is anyway, throw an
 * exception with the given message.
 */
export declare function throwUnreachable(_unreachable: never, message: string): void;