import type { PipeStep } from './pipe$.js';
import type { AnyAsyncIterable, AnyAwaitableIterable, AnyIterable, AsyncIteratedValue, IteratedValue } from './types/inputs/MinimalIterator.js';
import type { AnySubscribable } from './types/inputs/Subscribable.js';
import type { Observable } from './types/outputs/Observable.js';
import type { SimpleAsyncIterator, SimpleIterator } from './types/outputs/SimpleIterator.js';
import type { PredicateFn } from './types/utils.js';
export type FilterOrigin<D = unknown> = AnyAwaitableIterable<D> | AnySubscribable<D>;
export type FilterOriginValue<O extends FilterOrigin> = (O extends AnyIterable ? IteratedValue<O> : O extends AnyAsyncIterable ? AsyncIteratedValue<O> : unknown) & (O extends AnySubscribable<infer D> ? D : unknown);
export type FilterResult<O, R> = (O extends AnyIterable ? SimpleIterator<R> : O extends AnyAsyncIterable ? SimpleAsyncIterator<R> : unknown) & (O extends AnySubscribable ? Observable<R> : unknown);
/**
 * Filters emitted values using given predicate
 * @param predicate
 *
 * @since 1.0.0
 * @version 2.5.0 adds support for async iterators
 */
export declare function filter$<O extends FilterOrigin, R extends FilterOriginValue<O>>(predicate: PredicateFn<FilterOriginValue<O>, R>): PipeStep<O, FilterResult<O, R>>;
/**
 * Filters emitted values using given predicate
 *
 * @since 1.0.0
 * @version 2.5.0 Add support for async iterators
 */
export declare function filter$<O extends FilterOrigin>(predicate: (val: FilterOriginValue<O>) => boolean): PipeStep<O, FilterResult<O, FilterOriginValue<O>>>;