import { IndexedPredicate } from "../types/IndexedPredicate";
import { TypeGuardPredicate } from "../types/TypeGuardPredicate";
/**
 * Filters items from a source iterable using a predicate, optionally narrowing the element type.
 *
 * @typeParam T - Element type produced by the source iterable.
 * @typeParam S - Narrowed element type when `pred` acts as a type guard.
 * @param pred - Predicate invoked with each element and its index to determine inclusion.
 * @returns A transformer that yields every element for which `pred` returns a truthy value.
 * @throws Error Rethrows any error thrown by `pred`.
 * @example
 * ```ts
 * const odds = [
 *   ...pipeInto(
 *     [1, 2, 3, 4],
 *     filter((value) => value % 2 === 1)
 *   ),
 * ];
 * console.log(odds); // [1, 3]
 * ```
 */
export declare function filter<T, S extends T>(pred: TypeGuardPredicate<T, S>): (src: Iterable<T>) => Iterable<S>;
export declare function filter<T>(pred: IndexedPredicate<T>): (src: Iterable<T>) => Iterable<T>;
/**
 * Filters items from a source iterable using a predicate, optionally narrowing the element type.
 *
 * @typeParam T - Element type produced by the source iterable.
 * @typeParam S - Narrowed element type when `pred` acts as a type guard.
 * @param src - Source iterable evaluated synchronously.
 * @param pred - Predicate invoked with each element and its index to determine inclusion.
 * @returns A deferred iterable yielding every element for which `pred` returns a truthy value.
 * @throws Error Rethrows any error thrown by `pred`.
 * @example
 * ```ts
 * const odds = [..._filter([1, 2, 3, 4], (value) => value % 2 === 1)];
 * console.log(odds); // [1, 3]
 * ```
 */
export declare function _filter<T, S extends T>(src: Iterable<T>, pred: TypeGuardPredicate<T, S>): Iterable<S>;
export declare function _filter<T>(src: Iterable<T>, pred: IndexedPredicate<T>): Iterable<T>;