declare module 'gulp-yarn' {
  interface IGulpYarnOptions {
    /**
     * Using the `--production` flag, or when the NODE_ENV environment variable is set to production, Yarn will not install any package
     * listed in devDependencies.
     */
    production?: boolean;
    /**
     * Yarn will only install listed devDependencies.
     */
    dev?: boolean;
    /**
     * Only allow one version of a package. On the first run this will prompt you to choose a single version for each package that is
     * depended on at multiple version ranges.
     */
    flat?: boolean;
    /**
     * This refetches all packages, even ones that were previously installed.
     */
    force?: boolean;
    /**
     * Ignore all the required engines force by some packages.
     */
    ignoreEngines?: boolean;
    /**
     * None of `node_module` bin links getting created.
     */
    noBinLinks?: boolean;
    /**
     * Disable progress bar
     */
    noProgress?: boolean;
    /**
     * Don't read or generate a lockfile
     */
    noLockfile?: boolean;
    /**
     * Don't run npm scripts during installation
     */
    ignoreScripts?: boolean;
    /**
     * Using the `--non-interactive` flag of yarn to avoid that during the resolution (yarn install) a user input is needed.
     */
    nonInteractive?: boolean;
    /**
     * Pass any argument with `--` to execute with yarn
     */
    args?: string | string[];
  }

  const gulpYarn: (options?: IGulpYarnOptions) => NodeJS.ReadStream;

  export = gulpYarn;
}