import { type MapOrigin, type MapOriginValue, type MapResult } from './map$.js';
import type { PipeStep } from './pipe$.js';
import type { AssertionFn, PredicateFn } from './types/utils.js';
/**
 * Uses given assertion to validate emitted values.
 *
 * @since 1.0.0
 */
export declare function validate$<O extends MapOrigin, R extends MapOriginValue<O>>(assert: AssertionFn<MapOriginValue<O>, R>): PipeStep<O, MapResult<O, R>>;
/**
 * Uses given predicate to validate emitted values.
 * Use `onMiss` to customize default error, when predicated returns false.
 *
 * @since 1.0.0
 */
export declare function validate$<O extends MapOrigin, R extends MapOriginValue<O>>(predicate: PredicateFn<MapOriginValue<O>, R>, opts?: ValidatePredicateOpts<MapOriginValue<O>>): PipeStep<O, MapResult<O, R>>;
export interface ValidatePredicateOpts<in D = unknown> {
    /**
     * Called when predicate returns false. Should throw a meaningful error.
     */
    readonly onMiss?: (data: D) => never;
}
/**
 * Error thrown by validate$ on predicate miss.
 */
export declare class ValidateError<D = unknown> extends Error {
    readonly data: D;
    constructor(data: D);
}