/**
 * A queue to manage fetch requests with unique identification.
 *
 * Useful to deduplicate concurrent network calls to the same URL.
 *
 * @example
 * ```ts
 * const queue = new FetchQueue(fetch);
 * const [a, b] = await Promise.all([
 *   queue.addRequest('https://example.com/data'),
 *   queue.addRequest('https://example.com/data')
 * ]);
 * // only one HTTP request is performed
 * ```
 */
export default class FetchQueue {
    private queue;
    private isRunning;
    private fetchFn;
    /**
     *
     * @param {Function} fetchFn - A fetch function (e.g., node-fetch or window.fetch).
     */
    constructor(fetchFn: (url: string, options?: RequestInit) => Promise<any>);
    /**
     * Adds a fetch request to the queue.
     * @param {string} url - The URL to fetch.
     * @param {RequestInit} [options] - Optional fetch options.
     * @returns {Promise<any>} - A promise that resolves with the fetch response.
     */
    addRequest(url: string, options?: RequestInit): Promise<any>;
    /**
     * Runs the queue of fetch requests.
     */
    private runQueue;
    /**
     * Creates a hash to uniquely identify a request.
     * @param {string} url - The URL to fetch.
     * @param {RequestInit} [options] - Optional fetch options.
     * @returns {string} - A hash representing the unique request.
     */
    private createHash;
}