/** returns boolean */
export declare type CallBackFindIndex<T> = (value: T, index?: number, collection?: T[]) => Promise<boolean>;
/**
 * Async FindIndex function
 *
 * @export
 * @template T
 * @param {T[]} elements
 * @param {CallBackFind<T>} cb
 * @returns {Promise<number>}
 */
export declare function aFindIndex<T>(elements: T[], cb: CallBackFindIndex<T>): Promise<number>;