import { IterableX } from '../../iterable/iterablex';
/**
 * @ignore
 */
export declare function findIndexProto<T>(this: IterableX<T>, fn: (value: T, index: number) => boolean, thisArg?: any): number;
declare module '../../iterable/iterablex' {
    interface IterableX<T> {
        findIndex: typeof findIndexProto;
    }
}