/**
 * @author
 * @see https://github.com/herlandio
 *
 * Class to validate Brazilian CNPJ (Cadastro Nacional da Pessoa Jurídica).
 */
export declare class CNPJValidator {
    private readonly cnpj;
    /**
     * Constructor to initialize the CNPJ value.
     * @param cnpj - The CNPJ string to validate.
     */
    constructor(cnpj: string);
    /**
     * Validates the CNPJ.
     * @returns `true` if the CNPJ is valid; otherwise, `false`.
     */
    isValid(): boolean;
    /**
     * Checks if the CNPJ has the correct length of 14 digits.
     * @returns `true` if the length is valid; otherwise, `false`.
     */
    private isValidLength;
    /**
     * Checks if the CNPJ matches known invalid patterns, such as repeated sequences.
     * @returns `true` if the CNPJ is invalid; otherwise, `false`.
     */
    private isKnownInvalid;
    /**
     * Calculates a single check digit for a CNPJ based on the provided weights.
     * @param base - The numeric base string to validate against.
     * @param weights - The weights used in the calculation.
     * @returns The calculated check digit as a string.
     */
    private calculateCheckDigit;
}