codice_fiscale.js

'use strict';

var REGEX_CODICEFISCALE =/^([A-Za-z]{6}[0-9lmnpqrstuvLMNPQRSTUV]{2}[abcdehlmprstABCDEHLMPRST]{1}[0-9lmnpqrstuvLMNPQRSTUV]{2}[A-Za-z]{1}[0-9lmnpqrstuvLMNPQRSTUV]{3}[A-Za-z]{1})|([0-9]{11})$/;

var listDecOmocodia = {'A':'!','B':'!','C':'!','D':'!','E':'!','F':'!','G':'!','H':'!','I':'!','J':'!','K':'!','L':'0','M':'1','N':'2','O':'!','P':'3','Q':'4','R':'5','S':'6','T':'7','U':'8','V':'9','W':'!','X':'!','Y':'!','Z':'!'};

var listSostOmocodia = [6,7,9,10,12,13,14];

var listEvenChar = {'0':0,'1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9,'A':0,'B':1,'C':2,'D':3,'E':4,'F':5,'G':6,'H':7,'I':8,'J':9,'K':10,'L':11,'M':12,'N':13,'O':14,'P':15,'Q':16,'R':17,'S':18,'T':19,'U':20,'V':21,'W':22,'X':23,'Y':24,'Z':25};

var listOddChar = {'0':1,'1':0,'2':5,'3':7,'4':9,'5':13,'6':15,'7':17,'8':19,'9':21,'A':1,'B':0,'C':5,'D':7,'E':9,'F':13,'G':15,'H':17,'I':19,'J':21,'K':2,'L':4,'M':18,'N':20,'O':11,'P':3,'Q':6,'R':8,'S':12,'T':14,'U':16,'V':10,'W':22,'X':25,'Y':24,'Z':23};

var listCtrlCode = ['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'];

var listError = { 0 : 'Empty code', 1 : 'Len error', 2 : 'Code with wrong char', 3 : 'Code with wrong char in omocodia', 4 : 'Wrong code'};

module.exports = function checkCf(codiceFiscale){


    if(!codiceFiscale){
        throw new Error(listError[0]);
    }

    if(codiceFiscale.length !== 16){
        throw new Error(listError[1]);
    }

    if(! codiceFiscale.match(REGEX_CODICEFISCALE) ){
        throw new Error(listError[2]);
    }

    var cfCharList = codiceFiscale.toUpperCase().split('');

    listSostOmocodia.forEach(function(omocodiaIndex){
        var charAtIndex = cfCharList[omocodiaIndex];

        if ( isNaN(charAtIndex)  && listDecOmocodia[charAtIndex] ==='!'){
            throw new Error(listError[3]);
        }
    });

    var pari = 0;

    var dispari = listOddChar[cfCharList[14]];

    for(var i=0; i<13; i+=2){
        dispari += listOddChar[cfCharList[i]];
        pari += listEvenChar[cfCharList[i+1]];
    }

    var checksum = listCtrlCode[ (pari+dispari) % 26 ];

    if( checksum !== cfCharList[15] ){
        throw new Error(listError[4]);
    }

    return true;
};