import type { TypeError } from '@traversable/registry';
import type * as t from './schema.js';
export type Target<S> = S extends Guard<infer T> ? T : S extends Predicate<infer T> ? T : never;
export type $<S> = [keyof S] extends [never] ? unknown : S;
export interface Predicate<T = unknown> {
    (value: T): boolean;
    (value?: T): boolean;
}
export type InvalidItem = never | TypeError<'A required element cannot follow an optional element.'>;
export type Guard<T = unknown> = {
    (u: unknown): u is T;
};
export interface Typeguard<T = unknown> {
    (u: unknown): u is this['_type'];
    readonly _type: T;
}
export type { TypePredicate_ as TypePredicate };
type TypePredicate_<I = unknown, O = unknown> = never | TypePredicate<[I, O]>;
interface TypePredicate<T extends [unknown, unknown]> {
    (u: T[0]): u is T[1];
    (u: T[1]): boolean;
}
export type ValidateTuple<T extends readonly unknown[], LowerBound = t.optional<any>, V = ValidateOptionals<[...T], LowerBound>> = [V] extends [['ok']] ? T : V;
export type ValidateOptionals<S extends unknown[], LowerBound = t.optional<any>, Acc extends unknown[] = []> = LowerBound extends S[number] ? S extends [infer H, ...infer T] ? LowerBound extends H ? T[number] extends LowerBound ? ['ok'] : [...Acc, H, ...{
    [Ix in keyof T]: T[Ix] extends LowerBound ? T[Ix] : InvalidItem;
}] : ValidateOptionals<T, LowerBound, [...Acc, H]> : ['ok'] : ['ok'];
//# sourceMappingURL=types.d.ts.map