import { FindOptions } from '../../asynciterable/findoptions.js';
/**
 * @ignore
 */
export declare function findIndexProto<T>(this: AsyncIterable<T>, options: FindOptions<T>): Promise<number>;
declare module '../../asynciterable/asynciterablex' {
    interface AsyncIterableX<T> {
        findIndex: typeof findIndexProto;
    }
}