import type { Data } from "../util/data.js";
import type { Validator } from "../util/validate.js";
/** Options allowed by a `Schema` instance. */
export type SchemaOptions = {
    /** String for one of this thing, e.g. `product` or `item` or `sheep` */
    readonly one?: string;
    /** String for several of this thing, e.g. `products` or `items` or `sheep` (defaults to `one` + "s") */
    readonly many?: string;
    /** Title of the schema, e.g. for using as the title of a corresponding field. */
    readonly title?: string | undefined;
    /** Description of the schema, e.g. for using as a description in a corresponding field. */
    readonly description?: string | undefined;
    /** Placeholder of the schema, e.g. for using as a placeholder in a corresponding field. */
    readonly placeholder?: string | undefined;
    /** Default value for the schema if `validate()` is called with an `undefined` value. */
    readonly value?: unknown;
};
/**
 * Schema is an object instance with a `validate()` method.
 * - Type `T` represents the type of value `validate()` returns.
 * - `validate()` returns `Invalid` if value was not valid.
 */
export declare abstract class Schema<T = unknown> implements Validator<T> {
    /** String for one of this thing, e.g. `product` or `item` or `sheep` */
    readonly one: string;
    /** String for several of this thing, e.g. `products` or `items` or `sheep` (defaults to `one` + "s") */
    readonly many: string;
    /** Title of the schema, e.g. for using as the title of a corresponding field. */
    readonly title: string | undefined;
    /** Description of the schema, e.g. for using as a description in a corresponding field. */
    readonly description: string | undefined;
    /** Placeholder of the schema, e.g. for using as a placeholder in a corresponding field. */
    readonly placeholder: string | undefined;
    /** Default value for the schema if `validate()` is called with an `undefined` value. */
    readonly value: unknown;
    constructor({ one, many, title, description, placeholder, value }: SchemaOptions);
    /** Every schema must implement a `validate()` method. */
    abstract validate(unsafeValue: unknown): T;
    /** Format a validated value of this type as a string. */
    format(value: T): string;
}
/** Extract the type from a schema. */
export type SchemaType<X> = X extends Schema<infer Y> ? Y : never;
/** A set of named schemas in `{ name: schema }` format. */
export type Schemas<T extends Data = Data> = {
    readonly [K in keyof T]: Schema<T[K]>;
};
export declare const UNKNOWN: Schema<unknown>;
export declare const UNDEFINED: Schema<undefined>;
export declare const NULL: Schema<null>;