import type { AbstractIterator } from 'abstract-level';
import { AsyncIterator } from 'asynciterator';
export type MappingFn<I, O> = (val: I) => O;
export declare class LevelIterator<K, V, T> extends AsyncIterator<T> {
    #private;
    constructor(source: AbstractIterator<any, K, V>, mapper: MappingFn<[K, V], T>, maxBufferSize?: number);
    read(): T | null;
}