/**
 * Copyright (c) 2017-present A. Matías Quezada <amatiasq@gmail.com>
 */
/**
 * Decorates a promise-returning-function to cache the last returned value.
 * The returned function will have a `cached` method which will return the
 *   value used to fulfill the last successful call.
 *
 * @example
 * getServerStatus = syncVersion(getServerStatus);
 * getServerStatus()
 * // later...
 * // if the promise has been fulfilled this will return the value
 * getServerStatus.cached()
 *
 * @param {Function} fn Function to decorate.
 * @returns {Function} Decorated function
 */
export default function syncVersion<T>(fn: (...args: any[]) => Promise<T>): ICached<typeof fn, T>;
export declare type ICached<T extends () => Promise<U>, U> = T & {
    cached(): U;
};