/**
 * Class for queuing promises to be executed one after the other.
 * This is useful for tasks that should not be executed in parallel.
 * @example
 * const queue = new PromiseQueue();
 * queue.add(() => fetch('https://example.com/api/endpoint1'));
 * queue.add(() => fetch('https://example.com/api/endpoint2'));
 * // The second fetch will only be executed after the first one is done.
 */
export default class PromiseQueue {
    private queue;
    private pendingPromise;
    /**
     * Method to add a new promise to the queue and returns a promise that resolves when this task is done
     * @param task Function that returns a promise that will be added to the queue
     * @returns Promise that resolves when the task is done
     */
    add(task: () => Promise<any>): Promise<void>;
    /**
     * Method to check if there is a pending promise in the queue
     * @returns True if there is a pending promise, false otherwise
     */
    hasPendingPromise(): boolean;
    /**
     * Method to process the queue
     */
    private dequeue;
}