function to convert string input to date
function addTimeToArrayFromToken(token, input, config) {
        var a, datePartArray = config._a;

        switch (token) {
        // MONTH
        case 'M' : // fall through to MM
        case 'MM' :
            datePartArray[1] = (input == null) ? 0 : ~~input - 1;
            break;
        case 'MMM' : // fall through to MMMM
        case 'MMMM' :
            a = getLangDefinition(config._l).monthsParse(input);
            // if we didn't find a month name, mark the date as invalid.
            if (a != null) {
                datePartArray[1] = a;
            } else {
                config._isValid = false;
            }
            break;
        // DAY OF MONTH
        case 'D' : // fall through to DDDD
        case 'DD' : // fall through to DDDD
        case 'DDD' : // fall through to DDDD
        case 'DDDD' :
            if (input != null) {
                datePartArray[2] = ~~input;
            }
            break;
        // YEAR
        case 'YY' :
            datePartArray[0] = ~~input + (~~input > 68 ? 1900 : 2000);
            break;
        case 'YYYY' :
        case 'YYYYY' :
            datePartArray[0] = ~~input;
            break;
        // AM / PM
        case 'a' : // fall through to A
        case 'A' :
            config._isPm = getLangDefinition(config._l).isPM(input);
            break;
        // 24 HOUR
        case 'H' : // fall through to hh
        case 'HH' : // fall through to hh
        case 'h' : // fall through to hh
        case 'hh' :
            datePartArray[3] = ~~input;
            break;
        // MINUTE
        case 'm' : // fall through to mm
        case 'mm' :
            datePartArray[4] = ~~input;
            break;
        // SECOND
        case 's' : // fall through to ss
        case 'ss' :
            datePartArray[5] = ~~input;
            break;
        // MILLISECOND
        case 'S' :
        case 'SS' :
        case 'SSS' :
            datePartArray[6] = ~~ (('0.' + input) * 1000);
            break;
        // UNIX TIMESTAMP WITH MS
        case 'X':
            config._d = new Date(parseFloat(input) * 1000);
            break;
        // TIMEZONE
        case 'Z' : // fall through to ZZ
        case 'ZZ' :
            config._useUTC = true;
            config._tzm = timezoneMinutesFromString(input);
            break;
        }

        // if the input is null, the date is not valid
        if (input == null) {
            config._isValid = false;
        }
    }