import { AsyncPredicate, Predicate } from '@naturalcycles/js-lib';
import { TransformOptions, TransformTyped } from '../stream.model';
/**
 * Note, that currently it's NOT concurrent! (concurrency = 1)
 * So, it's recommended to use transformMap instead, that is both concurrent and has
 * filtering feature by default.
 */
export declare function transformFilter<IN = any>(predicate: AsyncPredicate<IN>, opt?: TransformOptions): TransformTyped<IN, IN>;
/**
 * Sync version of `transformFilter`
 */
export declare function transformFilterSync<IN = any>(predicate: Predicate<IN>, opt?: TransformOptions): TransformTyped<IN, IN>;