interface Options {
    /**
     * Setting this option true makes 0 regarded as a natural number.
     */
    includeZero: boolean;
}

/**
 * Rreturns true if the first argument is one of the natural numbers.
 * If not, or the argument is not a number, it returns false.
 */
declare function isNaturalNumber(number: number | string, option?: Options): boolean;

export = isNaturalNumber;