/**
 * @license
 * Copyright (c) 2020 The Polymer Project Authors. All rights reserved.
 * This code may only be used under the BSD style license found at
 * http://polymer.github.io/LICENSE.txt The complete set of authors may be found
 * at http://polymer.github.io/AUTHORS.txt The complete set of contributors may
 * be found at http://polymer.github.io/CONTRIBUTORS.txt Code distributed by
 * Google as part of the polymer project is also subject to an additional IP
 * rights grant found at http://polymer.github.io/PATENTS.txt
 */
export declare type OnDemandDependencies = Map<string, string>;
/**
 * Asynchronously checks to see if a module is resolvable. This gives the
 * invoker information that is similar to what they would get from using
 * require.resolve. However, require.resolve is backed by an unclearable
 * internal cache, which this helper bypasses via a child process.
 *
 * @see https://github.com/nodejs/node/issues/31803
 */
export declare const assertResolvable: (id: string) => Promise<void>;
export interface ContainsOnDemandDependencies {
    [index: string]: unknown;
    installsOnDemand?: string[];
}
export declare const getPackageJSONPath: () => Promise<string | null>;
export declare const getPackageRoot: () => Promise<string | null>;
/**
 * Extract a map of allowed "on-demand" dependencies from a given
 * package.json-shaped object.
 */
export declare const onDemandDependenciesFromPackageJSON: (packageJSON: ContainsOnDemandDependencies) => OnDemandDependencies;
/**
 * So-called "on-demand" dependencies are any packages that match the
 * following requirements:
 *
 *  - They are enumerated in the non-normative package.json field
 *    "installsOnDemand"
 *
 * This function resolves a map of package names and semver ranges including all
 * packages that match these requirements.
 */
export declare const getOnDemandDependencies: () => Promise<OnDemandDependencies>;
/**
 * Install an "on-demand" package, resolving after the package has been
 * installed. Only packages designated as installable on-demand can be
 * installed this way (see documentation for "getOnDemandDependenies" for more
 * details). An attempt to install any other package this way will be rejected.
 *
 * On-demand packages are installed to this package's node_modules directory.
 * Any package that can already be resolved from this package's root directory
 * will be skipped.
 */
export declare const installOnDemand: (packageName: string) => Promise<void>;