/**
 * Lock all concurrent calls to a resource to one promise for a set duration of time.
 * @param {string} key - Unique key to identify the promise.
 * @param {() => Promise<T>} promiseFunc - Function that will return the promise to be run only once.
 * @param {number} duration - Duration to hold on to the promise result. (default=1)
 * @returns {Promise<T>} Returns the single promise that will be fullfilled for all promises with the same key.
 * @example
 * // returns Promise<string>
 * var initTests = await promiseLock<string>("initTests", async () => { ... }, 2);
 */
export declare function promiseLock<T>(key: string, promiseFunc: () => Promise<T>, duration?: number): Promise<T>;
/**
 * Ensures that a promise runs only once
 * @param {string} key - Unique key to identify the promise.
 * @param {() => Promise<T>} promiseFunc - Function that will return the promise to be run only once.
 * @param {(result: T) => Promise<boolean>} isValidResult - Optional function that returns boolean to indicate if the result returned
 * by the promise is valid and should be kepy in memory.
 * @returns {Promise<T>} Returns the single promise that will be fullfilled for all promises with the same key.
 * @example
 * // returns Promise<string>
 * var initTests = await promiseOnce<string>("initTests", async () => { ... });
 */
export declare function promiseOnce<T>(key: string, promiseFunc: () => Promise<T>, isValidResult?: (result: T) => Promise<boolean>): Promise<T>;
/**
 * Runs all promises in sequential order.
 * @param {(() => Promise<T>)[]} asyncFuncs - Array of functions that return the promises to fullfill.
 * @returns {Promise<T[]>} Returns a single promise with a merged array of results that are in the same order as the
 * provided promise functions
 */
export declare function promiseAllSequential<T = any>(asyncFuncs: (() => Promise<T>)[]): Promise<T[]>;
/**
 * Runs N promises in parallel.
 * @param {(() => Promise<T>)[]} asyncFuncs - Array of functions that return the promises to fullfill.
 * @param {number} [maxParallel] - Max number of promises to run in parallel (default=8).
 * @returns {Promise<T[]>} Returns a single promise with a merged array of results that are in the same order as the
 * provided promise functions
 */
export declare function promiseNParallel<T>(asyncFuncs: (() => Promise<T>)[], maxParallel?: number): Promise<T[]>;
/**
 * Provides an asnyc sleep function that allows you to delay async/wait calls.
 * @param {number} [seconds] - Time to sleep in seconds.
 */
export declare function sleepAsync(seconds?: number): Promise<void>;
/**
 * Provides the ability to retry an async function n times with a optional delay between calls
 * @param {(...args) => Promise<T>} fn - Function to retry,
 * @param {number} numberOfRetries - Number of times to retry.
 * @param {number} [seconds] - Delay between retries in seconds (default=1).
 */
export declare function retryAsync<T>(fn: (...args: any[]) => Promise<T>, numberOfRetries: number, seconds?: number): Promise<T>;