import AllValidator from "./AllValidator";
import { ValidateFunction } from "./types";
/**
 * Validator for String parameters, which includes multiple String validation methods.
 */
declare class StringValidator<O extends boolean = false, N extends boolean = false> extends AllValidator<string, O, N> {
    #private;
    output: string;
    constructor();
    custom(fn: ValidateFunction): this;
    optional(): StringValidator<true>;
    /**
     * Set minimum length of a string.
     * Returns true if string length >= min.
     * This method will be tested when StringValidator.result() is called.
     * @param {number} min minimum length
     * @returns {StringValidator} StringValidator
     */
    minLength(min: number): this;
    /**
     * Set maximum length of a string.
     * Returns true if string length <= max.
     * This method will be tested when StringValidator.result() is called.
     * @param {number} max maximum length
     * @returns {StringValidator} StringValidator
     */
    maxLength(max: number): this;
    /**
     * Check if string is numeric.
     * Returns true if string is numeric.
     * This method will be tested when StringValidator.result() is called.
     * @returns {StringValidator} StringValidator
     */
    numeric(): this;
    /**
     * Set fixed length of a numeric string.
     * Returns true if the fixed length equals.
     * This method will be tested when StringValidator.result() is called.
     * @param {number} len fixed length
     * @returns {StringValidator} StringValidator
     */
    toFixed(len: number): this;
    /**
     * Use customized Regular Expression.
     * Returns true if the Regular Expression matches.
     * This method will be tested when StringValidator.result() is called.
     * @param {RegExp} re self defined Regular Expression
     * @returns {StringValidator} StringValidator
     */
    useRE(re: RegExp): this;
    /**
     * Check if string is an email.
     * Returns true if the (default) Regular Expression matches.
     * This method will be tested when StringValidator.result() is called.
     * @param {?RegExp} emailRE self defined email-checking Regular Expression
     * @returns {StringValidator} StringValidator
     */
    email(emailRE?: RegExp): this;
    /**
     * Check if string is a phone number.
     * Returns true if the (default) Regular Expression matches.
     * This method will be tested when StringValidator.result() is called.
     * @param {?RegExp} phoneRE self defined phone-checking Regular Expression
     * @returns {StringValidator} StringValidator
     */
    phone(phoneRE?: RegExp): this;
    /**
     * Check if string is a boolean string.
     * Returns true if string === 'true'.
     * This method will be tested when StringValidator.result() is called.
     * @returns {StringValidator} StringValidator
     */
    booleanStr(): this;
    /**
     * Check if string is one of the array elements.
     * Returns true if the string is in the array.
     * This method will be tested when StringValidator.result() is called.
     * @param {string[]} arr string set
     * @returns {StringValidator} StringValidator
     */
    oneof(arr: string[]): this;
    test(p?: any): boolean;
}
export default StringValidator;