import { Constraint } from '@xh/hoist/data';
import { LocalDate } from '@xh/hoist/utils/datetime';
/**
 * A set of validation functions to assist in form field validation.
 */
/**
 * Validate that a value is not null or undefined.
 * For strings this validation will fail if empty or containing only whitespace.
 * For arrays (e.g. Select w/multiple values) this validation will fail if empty.
 */
export declare const required: Constraint;
/**
 * Validate a single email address in a field that expects only one email address.
 */
export declare const validEmail: Constraint<string>;
/**
 * Validate all email addresses in a field that allows multiple email addresses
 * separated by a semicolon - the separator used by Outlook for multiple email addresses.
 * All email addresses must be unique.
 */
export declare function validEmails(c?: ValidEmailsOptions): Constraint<string>;
export interface ValidEmailsOptions {
    /** Require at least N email addresses. */
    minCount?: number;
    /** Require no more than N email addresses. */
    maxCount?: number;
}
/** Validate length of a string.*/
export declare function lengthIs(c: LengthIsOptions): Constraint<string>;
export interface LengthIsOptions {
    min?: number;
    max?: number;
}
/** Validate amount of a number */
export declare function numberIs(c: NumberIsOptions): Constraint<number>;
export interface NumberIsOptions {
    /** Minimum value (value must be gte).*/
    min?: number;
    /** Maximum value (value must be lte).*/
    max?: number;
    gt?: number;
    lt?: number;
    /** True to disallow 0. */
    notZero?: boolean;
}
/** Validate a date or LocalDate against allowed min/max boundaries. */
export declare function dateIs(c: DateIsOptions): Constraint<Date | LocalDate>;
export interface DateIsOptions {
    /**
     * Earliest allowed value for the date to be checked.
     * Supports values 'now' (instant rule is run) and 'today' (any time on the current day).
     */
    min?: Date | LocalDate | 'now' | 'today';
    /**
     * Latest allowed value for the date to be checked.
     * Supports values 'now' (instant rule is run) and 'today' (any time on the current day).
     */
    max?: Date | LocalDate | 'now' | 'today';
    /** Custom date format to be used in validation message. */
    fmt?: string;
}
/**
 * Apply a constraint to an array of values, e.g values coming from a tag picker.
 *
 * @param constraint - the executed constraint function to use on each individual value.
 * @returns a constraint appropriate for an array of values.
 */
export declare function constrainAll<T>(constraint: Constraint<T>): Constraint<T[]>;
/**
 * Validate that a value does not contain specific strings or characters.
 * @param excludeVals - one or more strings to exclude
 */
export declare function stringExcludes(...excludeVals: string[]): Constraint<string>;
/** Validate that a value is JSON. */
export declare const isValidJson: Constraint;