Personnummer.js

'use strict';

(function (root, factory) {
  if (typeof define === 'function' && define.amd) {
    define(['moment'], factory);
  } else if (typeof module !== 'undefined' && module.exports) {
    module.exports = factory(require('moment'));
  } else {
    root.Personnummer = factory(root.moment);
  }
})(this, function (moment) {

    var COORDINATION_NUMBER_OFFSET = 60;
    var FORMAT_TRADITIONAL = "yymmdd-nnnx";
    var FORMAT_MODERN = "yyyymmddnnnx";

    var mockDate = null;

    function mod10(number) {
        var total = 0;
        for (var i = 0; i < number.length; i++) {
            var num = ((i % 2 === 0) ? (2 * number[i]) : number[i]).toString();
            for (var j = 0; j < num.length; j++) {
                total += parseInt(num[j], 10);
            }
        }

        return total % 10;
    }

    function getMod10Checksum(number) {
      var total = mod10(number);
      return (10 - total === 10) ? 0 : 10 - total;
    }

    function isMod10(number) {
      return mod10(number) === 0;
    }

    function tryParse(data) {
        var regex = /^(([0-9]{2})?([0-9]{2}))([0-9]{2})([0-9]{2})(-|\+)?([0-9]{3})([0-9])$/,
            match = regex.exec(data);

        if (!match) {
            return false;
        }

        this.personnummer = data;
        this.century = match[2];
        this.year = match[3];
        this.month = match[4];
        this.day = match[5];
        this.separator = match[6];
        this.number = match[7];
        this.checksum = match[8];

        if (!isMod10([this.year, this.month, this.day, this.number, this.checksum].join(""))) {
            return false;
        }

        if (!this.separator) {
          this.separator = this.getAge() >= 100 ? '+' : '-';
        }

        return true;
    }

    function getNow() {
        if (mockDate instanceof Date) {
            return mockDate;
        }

        return new Date();
    }

    function diffYears(dateA, dateB) {
        return Math.floor(moment(dateA).diff(dateB, "years"));
    }

    var Personnummer = function Personnummer (data) {
        var self = this;

        self.personnummer = undefined;
        self.century = undefined;
        self.year = undefined;
        self.month = undefined;
        self.day = undefined;
        self.separator = undefined;
        self.number = undefined;
        self.checksum = undefined;

        self.getDateOfBirth = function () {
            var year = parseInt(self.year, 10),
                month = parseInt(self.month, 10) - 1,
                day = parseInt(self.day, 10),
                now = getNow();

            if (day > COORDINATION_NUMBER_OFFSET) {
                day -= COORDINATION_NUMBER_OFFSET;
            }

            if (self.century) {
                year += parseInt(self.century, 10) * 100;
            } else {
                year += Math.floor(now.getFullYear() / 100) * 100;
                if (new Date(year, month, day) >= now) {
                    year -= 100;
                }

                if (self.separator === "+") {
                    year -= 100;
                }
            }

            return new Date(year, month, day);
        };

        self.format = function (format) {
            if (!format) {
                format = FORMAT_TRADITIONAL;
            }

            var dateOfBirth = self.getDateOfBirth(),
                formatSpecifiers = {
                    'yyyy': dateOfBirth.getFullYear(),
                    'yy': self.year,
                    'mm': self.month,
                    'dd': self.day,
                    '-': self.separator,
                    'nnn': self.number,
                    'x': self.checksum
                },
                result = '';

            for (var i=0; i < format.length; i++) {
                var c = format[i];

                if (c === "\\" && i + 1 < format.length) {
                    i++;
                    result += format[i];
                    continue;
                }

                for (var specifier in formatSpecifiers) {
                    if (formatSpecifiers.hasOwnProperty(specifier)) {
                        if (i + specifier.length - 1 < format.length && format.substr(i, specifier.length) === specifier) {
                            i += specifier.length - 1;
                            result += formatSpecifiers[specifier];
                            break;
                        }
                    }
                }
            }

            return result;
        };

        self.toString = function (format) {
            return self.format(format);
        };

        self.toModernString = function () {
            return self.toString(FORMAT_MODERN);
        };

        self.toTraditionalString = function () {
            return self.toString(FORMAT_TRADITIONAL);
        };

        self.getAge = function (now) {
            if (!(now instanceof Date)) {
                now = getNow();
            }

            return diffYears(now, self.getDateOfBirth());
        };

        if (typeof data !== "undefined") {
            if (!tryParse.call(self, data)) {
                throw new Error("Invalid personnummer: " + data);
            }
        }
    };

    Personnummer.FORMAT_MODERN = FORMAT_MODERN;
    Personnummer.FORMAT_TRADITIONAL = FORMAT_TRADITIONAL;
    Personnummer.COORDINATION_NUMBER_OFFSET = COORDINATION_NUMBER_OFFSET;

    Personnummer.parse = function (data) {
        return new Personnummer(data);
    };

    Personnummer.tryParse = function (data) {
        var personnummer = new Personnummer();
        if (!tryParse.call(personnummer, data)) {
            return false;
        }

        return personnummer;
    };

    Personnummer.isValid = function (data) {
        return !!Personnummer.tryParse(data);
    };

    Personnummer.getDateOfBirth = function (data) {
        return (new Personnummer(data)).getDateOfBirth();
    };

    Personnummer.format = function (data, format) {
        return (new Personnummer(data)).toString(format);
    };

    Personnummer.getAge = function (data, now) {
        return (new Personnummer(data)).getAge(now);
    };

    Personnummer.generate = function (dateOfBirth, numbers) {
        function padLeft(s, padWidth, padCharacter) {
          s = s + '';
          return s.length >= padWidth ? s : new Array(padWidth - s.length + 1).join(padCharacter || '0') + s;
        }

        if (!numbers) {
          numbers = "000";
        }

        var data;        
        data = dateOfBirth.getFullYear().toString().substr(-2);
        data += padLeft(dateOfBirth.getMonth() + 1, 2);
        data += padLeft(dateOfBirth.getDate(), 2);
        data += numbers;

        return Personnummer.tryParse(data + getMod10Checksum(data));
    };

    Personnummer.mockDate = function (date) {
        mockDate = date;
    };

    return Personnummer;
});