Spanish DNI, CIF, NIE validator

gistfile1.txt

/**
 * ValidateSpanishID. Returns the type of document and checks its validity.
 * 
 * Usage:
 *     ValidateSpanishID( str );
 * 
 *     > ValidateSpanishID( '12345678Z' );
 *     // { type: 'dni', valid: true }
 *     
 *     > ValidateSpanishID( 'B83375575' );
 *     // { type: 'cif', valid: false }
 * 
 * The algorithm is adapted from other solutions found at:
 * - http://www.compartecodigo.com/javascript/validar-nif-cif-nie-segun-ley-vigente-31.html
 * - http://es.wikipedia.org/wiki/C%C3%B3digo_de_identificaci%C3%B3n_fiscal
 */
ValidateSpanishID = (function() {
    'use strict';

    var DNI_REGEX = /^(\d{8})([A-Z])$/;
    var CIF_REGEX = /^([ABCDEFGHJKLMNPQRSUVW])(\d{7})([0-9A-J])$/;
    var NIE_REGEX = /^[XYZ]\d{7,8}[A-Z]$/;

    var ValidateSpanishID = function( str ) {
        // Ensure upcase and remove whitespace
        str = str.toUpperCase().replace(/\s/, '');

        var valid = false;
        var type = spainIdType( str );

        switch (type) {
            case 'dni':
                valid = validDNI( str );
                break;
            case 'nie':
                valid = validNIE( str );
                break;
            case 'cif':
                valid = validCIF( str );
                break;
        }

        return {
            type: type,
            valid: valid
        };
    };

    var spainIdType = function( str ) {
        if ( str.match( DNI_REGEX ) ) {
            return 'dni';
        }
        if ( str.match( CIF_REGEX ) ) {
            return 'cif';
        }
        if ( str.match( NIE_REGEX ) ) {
            return 'nie';
        }
    };

    var validDNI = function( dni ) {
        var dni_letters = "TRWAGMYFPDXBNJZSQVHLCKE";
        var letter = dni_letters.charAt( parseInt( dni, 10 ) % 23 );

        return letter == dni.charAt(8);
    };

    var validNIE = function( nie ) {
        // Change the initial letter for the corresponding number and validate as DNI
        var nie_prefix = nie.charAt( 0 );
        switch (nie_prefix) {
            case 'X': nie_prefix = 0; break;
            case 'Y': nie_prefix = 1; break;
            case 'Z': nie_prefix = 2; break;
        }
        return validDNI( nie_prefix + nie.substr(1) );
    };

    var validCIF = function( cif ) {
        var match = cif.match( CIF_REGEX );
        var letter  = match[1],
        number  = match[2],
        control = match[3];

        var even_sum = 0;
        var odd_sum = 0;
        var n;

        for ( var i = 0; i < number.length; i++) {
            n = parseInt( number[i], 10 );
            // Odd positions (Even index equals to odd position. i=0 equals first position)
            if ( i % 2 === 0 ) {
                // Odd positions are multiplied first.
                n *= 2;
                // If the multiplication is bigger than 10 we need to adjust
                odd_sum += n < 10 ? n : n - 9;
                // Even positions
                // Just sum them
            } else {
                even_sum += n;
            }
        }

        // var control_digit = (10 - (even_sum + odd_sum).toString().substr(-1) );
        var control_digit = (10 - (even_sum + odd_sum).toString().substr(-1)).toString().substr(-1) ;
        var control_letter = 'JABCDEFGHI'.substr( control_digit, 1 );

        // Control must be a digit
        if ( letter.match( /[ABEH]/ ) ) {
            return control == control_digit;
            // Control must be a letter
        } else if ( letter.match( /[KPQS]/ ) ) {
            return control == control_letter;
            // Can be either
        } else {
            return control == control_digit || control == control_letter;
        }
    };

    return ValidateSpanishID;
})();