import { Context } from "koa";
import { Checkbox } from "../controls/checkbox.js";
import { FormDataValue } from "../form-types.js";
import { FieldParseResult, FormField } from "./field.js";
import { FormControlContext } from "../controls/form-control.js";
export declare class Boolean<Required extends boolean> extends FormField<Required, boolean, Checkbox> {
    error_message: string;
    predicate: (v: unknown, w: unknown) => {
        readonly match: boolean;
        readonly wildcard: boolean;
    };
    constructor(required: Required, error_message?: string);
    isValueValid(_: Context, value: boolean): Promise<{
        valid: boolean;
        message: string;
    }>;
    parse(_: Context, value: FormDataValue): Promise<FieldParseResult<boolean>>;
    getEmptyValue(): boolean;
    getControl(): Checkbox;
    getSealiousCreateValue(fctx: FormControlContext): Promise<boolean>;
    sealiousValueToForm(_: Context, value: boolean | null): Promise<FormDataValue>;
}