index.js

        d  : 'a day',
        dd : '%d days',
        M  : 'a month',
        MM : '%d months',
        y  : 'a year',
        yy : '%d years'
    };

    function relativeTime (number, withoutSuffix, string, isFuture) {
        var output = this._relativeTime[string];
        return (isFunction(output)) ?
            output(number, withoutSuffix, string, isFuture) :
            output.replace(/%d/i, number);
    }

    function pastFuture (diff, output) {
        var format = this._relativeTime[diff > 0 ? 'future' : 'past'];
        return isFunction(format) ? format(output) : format.replace(/%s/i, output);
    }

    var aliases = {};

    function addUnitAlias (unit, shorthand) {
        var lowerCase = unit.toLowerCase();
        aliases[lowerCase] = aliases[lowerCase + 's'] = aliases[shorthand] = unit;
    }

    function normalizeUnits(units) {
        return typeof units === 'string' ? aliases[units] || aliases[units.toLowerCase()] : undefined;
    }

    function normalizeObjectUnits(inputObject) {
        var normalizedInput = {},
            normalizedProp,
            prop;

        for (prop in inputObject) {
            if (hasOwnProp(inputObject, prop)) {
                normalizedProp = normalizeUnits(prop);
                if (normalizedProp) {
                    normalizedInput[normalizedProp] = inputObject[prop];
                }
            }
        }

        return normalizedInput;
    }

    var priorities = {};

    function addUnitPriority(unit, priority) {
        priorities[unit] = priority;
    }

    function getPrioritizedUnits(unitsObj) {
        var units = [];
        for (var u in unitsObj) {
            units.push({unit: u, priority: priorities[u]});
        }
        units.sort(function (a, b) {
            return a.priority - b.priority;
        });
        return units;
    }

    function zeroFill(number, targetLength, forceSign) {
        var absNumber = '' + Math.abs(number),
            zerosToFill = targetLength - absNumber.length,
            sign = number >= 0;
        return (sign ? (forceSign ? '+' : '') : '-') +
            Math.pow(10, Math.max(0, zerosToFill)).toString().substr(1) + absNumber;
    }

    var formattingTokens = /(\[[^\[]*\])|(\\)?([Hh]mm(ss)?|Mo|MM?M?M?|Do|DDDo|DD?D?D?|ddd?d?|do?|w[o|w]?|W[o|W]?|Qo?|YYYYYY|YYYYY|YYYY|YY|gg(ggg?)?|GG(GGG?)?|e|E|a|A|hh?|HH?|kk?|mm?|ss?|S{1,9}|x|X|zz?|ZZ?|.)/g;

    var localFormattingTokens = /(\[[^\[]*\])|(\\)?(LTS|LT|LL?L?L?|l{1,4})/g;

    var formatFunctions = {};

    var formatTokenFunctions = {};

    // token:    'M'
    // padded:   ['MM', 2]
    // ordinal:  'Mo'
    // callback: function () { this.month() + 1 }
    function addFormatToken (token, padded, ordinal, callback) {
        var func = callback;
        if (typeof callback === 'string') {
            func = function () {
                return this[callback]();
            };
        }
        if (token) {
            formatTokenFunctions[token] = func;
        }
        if (padded) {
            formatTokenFunctions[padded[0]] = function () {
                return zeroFill(func.apply(this, arguments), padded[1], padded[2]);
            };
        }
        if (ordinal) {
            formatTokenFunctions[ordinal] = function () {
                return this.localeData().ordinal(func.apply(this, arguments), token);
            };
        }
    }

    function removeFormattingTokens(input) {
        if (input.match(/\[[\s\S]/)) {
            return input.replace(/^\[|\]$/g, '');
        }
        return input.replace(/\\/g, '');
    }

    function makeFormatFunction(format) {
        var array = format.match(formattingTokens), i, length;

        for (i = 0, length = array.length; i < length; i++) {
            if (formatTokenFunctions[array[i]]) {
                array[i] = formatTokenFunctions[array[i]];
            } else {
                array[i] = removeFormattingTokens(array[i]);
            }
        }

        return function (mom) {
            var output = '', i;
            for (i = 0; i < length; i++) {
                output += isFunction(array[i]) ? array[i].call(mom, format) : array[i];
            }
            return output;
        };
    }

    // format date using native date object
    function formatMoment(m, format) {
        if (!m.isValid()) {
            return m.localeData().invalidDate();
        }

        format = expandFormat(format, m.localeData());
        formatFunctions[format] = formatFunctions[format] || makeFormatFunction(format);

        return formatFunctions[format](m);
    }

    function expandFormat(format, locale) {
        var i = 5;

        function replaceLongDateFormatTokens(input) {
            return locale.longDateFormat(input) || input;
        }

        localFormattingTokens.lastIndex = 0;
        while (i >= 0 && localFormattingTokens.test(format)) {
            format = format.replace(localFormattingTokens, replaceLongDateFormatTokens);
            localFormattingTokens.lastIndex = 0;
            i -= 1;
        }

        return format;
    }

    var match1         = /\d/;            //       0 - 9
    var match2         = /\d\d/;          //      00 - 99
    var match3         = /\d{3}/;         //     000 - 999
    var match4         = /\d{4}/;         //    0000 - 9999
    var match6         = /[+-]?\d{6}/;    // -999999 - 999999
    var match1to2      = /\d\d?/;         //       0 - 99
    var match3to4      = /\d\d\d\d?/;     //     999 - 9999
    var match5to6      = /\d\d\d\d\d\d?/; //   99999 - 999999
    var match1to3      = /\d{1,3}/;       //       0 - 999
    var match1to4      = /\d{1,4}/;       //       0 - 9999
    var match1to6      = /[+-]?\d{1,6}/;  // -999999 - 999999

    var matchUnsigned  = /\d+/;           //       0 - inf
    var matchSigned    = /[+-]?\d+/;      //    -inf - inf

    var matchOffset    = /Z|[+-]\d\d:?\d\d/gi; // +00:00 -00:00 +0000 -0000 or Z
    var matchShortOffset = /Z|[+-]\d\d(?::?\d\d)?/gi; // +00 -00 +00:00 -00:00 +0000 -0000 or Z

    var matchTimestamp = /[+-]?\d+(\.\d{1,3})?/; // 123456789 123456789.123

    // any word (or two) characters or numbers including two/three word month in arabic.
    // includes scottish gaelic two word and hyphenated months
    var matchWord = /[0-9]{0,256}['a-z\u00A0-\u05FF\u0700-\uD7FF\uF900-\uFDCF\uFDF0-\uFF07\uFF10-\uFFEF]{1,256}|[\u0600-\u06FF\/]{1,256}(\s*?[\u0600-\u06FF]{1,256}){1,2}/i;

    var regexes = {};

    function addRegexToken (token, regex, strictRegex) {
        regexes[token] = isFunction(regex) ? regex : function (isStrict, localeData) {
            return (isStrict && strictRegex) ? strictRegex : regex;
        };
    }

    function getParseRegexForToken (token, config) {
        if (!hasOwnProp(regexes, token)) {
            return new RegExp(unescapeFormat(token));
        }

        return regexes[token](config._strict, config._locale);
    }

    // Code from http://stackoverflow.com/questions/3561493/is-there-a-regexp-escape-function-in-javascript
    function unescapeFormat(s) {
        return regexEscape(s.replace('\\', '').replace(/\\(\[)|\\(\])|\[([^\]\[]*)\]|\\(.)/g, function (matched, p1, p2, p3, p4) {
            return p1 || p2 || p3 || p4;
        }));
    }

    function regexEscape(s) {
        return s.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
    }

    var tokens = {};

    function addParseToken (token, callback) {
        var i, func = callback;
        if (typeof token === 'string') {
            token = [token];
        }
        if (isNumber(callback)) {
            func = function (input, array) {
                array[callback] = toInt(input);
            };
        }
        for (i = 0; i < token.length; i++) {
            tokens[token[i]] = func;
        }
    }

    function addWeekParseToken (token, callback) {
        addParseToken(token, function (input, array, config, token) {
            config._w = config._w || {};
            callback(input, config._w, config, token);
        });
    }

    function addTimeToArrayFromToken(token, input, config) {
        if (input != null && hasOwnProp(tokens, token)) {
            tokens[token](input, config._a, config, token);
        }
    }

    var YEAR = 0;
    var MONTH = 1;
    var DATE = 2;
    var HOUR = 3;
    var MINUTE = 4;
    var SECOND = 5;
    var MILLISECOND = 6;
    var WEEK = 7;
    var WEEKDAY = 8;

    // FORMATTING

    addFormatToken('Y', 0, 0, function () {
        var y = this.year();
        return y <= 9999 ? '' + y : '+' + y;
    });

    addFormatToken(0, ['YY', 2], 0, function () {
        return this.year() % 100;
    });

    addFormatToken(0, ['YYYY',   4],       0, 'year');
    addFormatToken(0, ['YYYYY',  5],       0, 'year');
    addFormatToken(0, ['YYYYYY', 6, true], 0, 'year');

    // ALIASES

    addUnitAlias('year', 'y');

    // PRIORITIES

    addUnitPriority('year', 1);

    // PARSING

    addRegexToken('Y',      matchSigned);
    addRegexToken('YY',     match1to2, match2);
    addRegexToken('YYYY',   match1to4, match4);
    addRegexToken('YYYYY',  match1to6, match6);
    addRegexToken('YYYYYY', match1to6, match6);

    addParseToken(['YYYYY', 'YYYYYY'], YEAR);
    addParseToken('YYYY', function (input, array) {
        array[YEAR] = input.length === 2 ? hooks.parseTwoDigitYear(input) : toInt(input);
    });
    addParseToken('YY', function (input, array) {
        array[YEAR] = hooks.parseTwoDigitYear(input);
    });
    addParseToken('Y', function (input, array) {
        array[YEAR] = parseInt(input, 10);
    });

    // HELPERS

    function daysInYear(year) {
        return isLeapYear(year) ? 366 : 365;
    }

    function isLeapYear(year) {
        return (year % 4 === 0 && year % 100 !== 0) || year % 400 === 0;
    }

    // HOOKS

    hooks.parseTwoDigitYear = function (input) {
        return toInt(input) + (toInt(input) > 68 ? 1900 : 2000);
    };

    // MOMENTS

    var getSetYear = makeGetSet('FullYear', true);

    function getIsLeapYear () {
        return isLeapYear(this.year());
    }

    function makeGetSet (unit, keepTime) {
        return function (value) {
            if (value != null) {
                set$1(this, unit, value);
                hooks.updateOffset(this, keepTime);
                return this;
            } else {
                return get(this, unit);
            }
        };
    }

    function get (mom, unit) {
        return mom.isValid() ?
            mom._d['get' + (mom._isUTC ? 'UTC' : '') + unit]() : NaN;
    }

    function set$1 (mom, unit, value) {
        if (mom.isValid() && !isNaN(value)) {
            if (unit === 'FullYear' && isLeapYear(mom.year()) && mom.month() === 1 && mom.date() === 29) {
                mom._d['set' + (mom._isUTC ? 'UTC' : '') + unit](value, mom.month(), daysInMonth(value, mom.month()));
            }
            else {
                mom._d['set' + (mom._isUTC ? 'UTC' : '') + unit](value);
            }
        }
    }

    // MOMENTS

    function stringGet (units) {
        units = normalizeUnits(units);
        if (isFunction(this[units])) {
            return this[units]();
        }
        return this;
    }


    function stringSet (units, value) {
        if (typeof units === 'object') {
            units = normalizeObjectUnits(units);
            var prioritized = getPrioritizedUnits(units);
            for (var i = 0; i < prioritized.length; i++) {
                this[prioritized[i].unit](units[prioritized[i].unit]);
            }
        } else {
            units = normalizeUnits(units);
            if (isFunction(this[units])) {
                return this[units](value);
            }
        }
        return this;
    }

    function mod(n, x) {
        return ((n % x) + x) % x;
    }

    var indexOf;

    if (Array.prototype.indexOf) {
        indexOf = Array.prototype.indexOf;
    } else {
        indexOf = function (o) {
            // I know
            var i;
            for (i = 0; i < this.length; ++i) {
                if (this[i] === o) {
                    return i;
                }
            }
            return -1;
        };
    }

    function daysInMonth(year, month) {
        if (isNaN(year) || isNaN(month)) {
            return NaN;
        }
        var modMonth = mod(month, 12);
        year += (month - modMonth) / 12;
        return modMonth === 1 ? (isLeapYear(year) ? 29 : 28) : (31 - modMonth % 7 % 2);
    }

    // FORMATTING

    addFormatToken('M', ['MM', 2], 'Mo', function () {
        return this.month() + 1;
    });

    addFormatToken('MMM', 0, 0, function (format) {
        return this.localeData().monthsShort(this, format);
    });

    addFormatToken('MMMM', 0, 0, function (format) {
        return this.localeData().months(this, format);
    });

    // ALIASES

    addUnitAlias('month', 'M');

    // PRIORITY

    addUnitPriority('month', 8);

    // PARSING

    addRegexToken('M',    match1to2);
    addRegexToken('MM',   match1to2, match2);
    addRegexToken('MMM',  function (isStrict, locale) {
        return locale.monthsShortRegex(isStrict);
    });
    addRegexToken('MMMM', function (isStrict, locale) {
        return locale.monthsRegex(isStrict);
    });

    addParseToken(['M', 'MM'], function (input, array) {
        array[MONTH] = toInt(input) - 1;
    });

    addParseToken(['MMM', 'MMMM'], function (input, array, config, token) {
        var month = config._locale.monthsParse(input, token, config._strict);
        // if we didn't find a month name, mark the date as invalid.
        if (month != null) {
            array[MONTH] = month;
        } else {
            getParsingFlags(config).invalidMonth = input;
        }
    });

    // LOCALES

    var MONTHS_IN_FORMAT = /D[oD]?(\[[^\[\]]*\]|\s)+MMMM?/;
    var defaultLocaleMonths = 'January_February_March_April_May_June_July_August_September_October_November_December'.split('_');
    function localeMonths (m, format) {
        if (!m) {
            return isArray(this._months) ? this._months :
                this._months['standalone'];
        }
        return isArray(this._months) ? this._months[m.month()] :
            this._months[(this._months.isFormat || MONTHS_IN_FORMAT).test(format) ? 'format' : 'standalone'][m.month()];
    }

    var defaultLocaleMonthsShort = 'Jan_Feb_Mar_Apr_May_Jun_Jul_Aug_Sep_Oct_Nov_Dec'.split('_');
    function localeMonthsShort (m, format) {
        if (!m) {
            return isArray(this._monthsShort) ? this._monthsShort :
                this._monthsShort['standalone'];
        }
        return isArray(this._monthsShort) ? this._monthsShort[m.month()] :
            this._monthsShort[MONTHS_IN_FORMAT.test(format) ? 'format' : 'standalone'][m.month()];
    }

    function handleStrictParse(monthName, format, strict) {
        var i, ii, mom, llc = monthName.toLocaleLowerCase();
        if (!this._monthsParse) {
            // this is not used
            this._monthsParse = [];
            this._longMonthsParse = [];
            this._shortMonthsParse = [];
            for (i = 0; i < 12; ++i) {
                mom = createUTC([2000, i]);
                this._shortMonthsParse[i] = this.monthsShort(mom, '').toLocaleLowerCase();
                this._longMonthsParse[i] = this.months(mom, '').toLocaleLowerCase();
            }
        }

        if (strict) {
            if (format === 'MMM') {
                ii = indexOf.call(this._shortMonthsParse, llc);
                return ii !== -1 ? ii : null;
            } else {
                ii = indexOf.call(this._longMonthsParse, llc);
                return ii !== -1 ? ii : null;
            }
        } else {
            if (format === 'MMM') {
                ii = indexOf.call(this._shortMonthsParse, llc);
                if (ii !== -1) {
                    return ii;
                }
                ii = indexOf.call(this._longMonthsParse, llc);
                return ii !== -1 ? ii : null;
            } else {
                ii = indexOf.call(this._longMonthsParse, llc);
                if (ii !== -1) {
                    return ii;
                }
                ii = indexOf.call(this._shortMonthsParse, llc);
                return ii !== -1 ? ii : null;
            }
        }
    }

    function localeMonthsParse (monthName, format, strict) {
        var i, mom, regex;

        if (this._monthsParseExact) {
            return handleStrictParse.call(this, monthName, format, strict);
        }

        if (!this._monthsParse) {
            this._monthsParse = [];
            this._longMonthsParse = [];
            this._shortMonthsParse = [];
        }

        // TODO: add sorting
        // Sorting makes sure if one month (or abbr) is a prefix of another
        // see sorting in computeMonthsParse
        for (i = 0; i < 12; i++) {
            // make the regex if we don't have it already
            mom = createUTC([2000, i]);
            if (strict && !this._longMonthsParse[i]) {
                this._longMonthsParse[i] = new RegExp('^' + this.months(mom, '').replace('.', '') + '$', 'i');
                this._shortMonthsParse[i] = new RegExp('^' + this.monthsShort(mom, '').replace('.', '') + '$', 'i');
            }
            if (!strict && !this._monthsParse[i]) {
                regex = '^' + this.months(mom, '') + '|^' + this.monthsShort(mom, '');
                this._monthsParse[i] = new RegExp(regex.replace('.', ''), 'i');
            }
            // test the regex
            if (strict && format === 'MMMM' && this._longMonthsParse[i].test(monthName)) {
                return i;
            } else if (strict && format === 'MMM' && this._shortMonthsParse[i].test(monthName)) {
                return i;
            } else if (!strict && this._monthsParse[i].test(monthName)) {
                return i;
            }
        }
    }

    // MOMENTS

    function setMonth (mom, value) {
        var dayOfMonth;

        if (!mom.isValid()) {
            // No op
            return mom;
        }

        if (typeof value === 'string') {
            if (/^\d+$/.test(value)) {
                value = toInt(value);
            } else {
                value = mom.localeData().monthsParse(value);
                // TODO: Another silent failure?
                if (!isNumber(value)) {
                    return mom;
                }
            }
        }

        dayOfMonth = Math.min(mom.date(), daysInMonth(mom.year(), value));
        mom._d['set' + (mom._isUTC ? 'UTC' : '') + 'Month'](value, dayOfMonth);
        return mom;
    }

    function getSetMonth (value) {
        if (value != null) {
            setMonth(this, value);
            hooks.updateOffset(this, true);
            return this;
        } else {
            return get(this, 'Month');
        }
    }

    function getDaysInMonth () {
        return daysInMonth(this.year(), this.month());
    }

    var defaultMonthsShortRegex = matchWord;
    function monthsShortRegex (isStrict) {
        if (this._monthsParseExact) {
            if (!hasOwnProp(this, '_monthsRegex')) {
                computeMonthsParse.call(this);
            }
            if (isStrict) {
                return this._monthsShortStrictRegex;
            } else {
                return this._monthsShortRegex;
            }
        } else {
            if (!hasOwnProp(this, '_monthsShortRegex')) {
                this._monthsShortRegex = defaultMonthsShortRegex;
            }
            return this._monthsShortStrictRegex && isStrict ?
                this._monthsShortStrictRegex : this._monthsShortRegex;
        }
    }

    var defaultMonthsRegex = matchWord;
    function monthsRegex (isStrict) {
        if (this._monthsParseExact) {
            if (!hasOwnProp(this, '_monthsRegex')) {
                computeMonthsParse.call(this);
            }
            if (isStrict) {
                return this._monthsStrictRegex;
            } else {
                return this._monthsRegex;
            }
        } else {
            if (!hasOwnProp(this, '_monthsRegex')) {
                this._monthsRegex = defaultMonthsRegex;
            }
            return this._monthsStrictRegex && isStrict ?
                this._monthsStrictRegex : this._monthsRegex;
        }
    }

    function computeMonthsParse () {
        function cmpLenRev(a, b) {
            return b.length - a.length;
        }

        var shortPieces = [], longPieces = [], mixedPieces = [],
            i, mom;
        for (i = 0; i < 12; i++) {
            // make the regex if we don't have it already
            mom = createUTC([2000, i]);
            shortPieces.push(this.monthsShort(mom, ''));
            longPieces.push(this.months(mom, ''));
            mixedPieces.push(this.months(mom, ''));
            mixedPieces.push(this.monthsShort(mom, ''));
        }
        // Sorting makes sure if one month (or abbr) is a prefix of another it
        // will match the longer piece.
        shortPieces.sort(cmpLenRev);
        longPieces.sort(cmpLenRev);
        mixedPieces.sort(cmpLenRev);
        for (i = 0; i < 12; i++) {
            shortPieces[i] = regexEscape(shortPieces[i]);
            longPieces[i] = regexEscape(longPieces[i]);
        }
        for (i = 0; i < 24; i++) {
            mixedPieces[i] = regexEscape(mixedPieces[i]);
        }

        this._monthsRegex = new RegExp('^(' + mixedPieces.join('|') + ')', 'i');
        this._monthsShortRegex = this._monthsRegex;
        this._monthsStrictRegex = new RegExp('^(' + longPieces.join('|') + ')', 'i');
        this._monthsShortStrictRegex = new RegExp('^(' + shortPieces.join('|') + ')', 'i');
    }

    function createDate (y, m, d, h, M, s, ms) {
        // can't just apply() to create a date:
        // https://stackoverflow.com/q/181348
        var date;
        // the date constructor remaps years 0-99 to 1900-1999
        if (y < 100 && y >= 0) {
            // preserve leap years using a full 400 year cycle, then reset
            date = new Date(y + 400, m, d, h, M, s, ms);
            if (isFinite(date.getFullYear())) {
                date.setFullYear(y);
            }
        } else {
            date = new Date(y, m, d, h, M, s, ms);
        }

        return date;
    }

    function createUTCDate (y) {
        var date;
        // the Date.UTC function remaps years 0-99 to 1900-1999
        if (y < 100 && y >= 0) {
            var args = Array.prototype.slice.call(arguments);
            // preserve leap years using a full 400 year cycle, then reset
            args[0] = y + 400;
            date = new Date(Date.UTC.apply(null, args));
            if (isFinite(date.getUTCFullYear())) {
                date.setUTCFullYear(y);
            }
        } else {
            date = new Date(Date.UTC.apply(null, arguments));
        }

        return date;
    }

    // start-of-first-week - start-of-year
    function firstWeekOffset(year, dow, doy) {
        var // first-week day -- which january is always in the first week (4 for iso, 1 for other)
            fwd = 7 + dow - doy,
            // first-week day local weekday -- which local weekday is fwd
            fwdlw = (7 + createUTCDate(year, 0, fwd).getUTCDay() - dow) % 7;

        return -fwdlw + fwd - 1;
    }

    // https://en.wikipedia.org/wiki/ISO_week_date#Calculating_a_date_given_the_year.2C_week_number_and_weekday
    function dayOfYearFromWeeks(year, week, weekday, dow, doy) {
        var localWeekday = (7 + weekday - dow) % 7,
            weekOffset = firstWeekOffset(year, dow, doy),
            dayOfYear = 1 + 7 * (week - 1) + localWeekday + weekOffset,
            resYear, resDayOfYear;

        if (dayOfYear <= 0) {
            resYear = year - 1;
            resDayOfYear = daysInYear(resYear) + dayOfYear;
        } else if (dayOfYear > daysInYear(year)) {
            resYear = year + 1;
            resDayOfYear = dayOfYear - daysInYear(year);
        } else {
            resYear = year;
            resDayOfYear = dayOfYear;
        }

        return {
            year: resYear,
            dayOfYear: resDayOfYear
        };
    }

    function weekOfYear(mom, dow, doy) {
        var weekOffset = firstWeekOffset(mom.year(), dow, doy),
            week = Math.floor((mom.dayOfYear() - weekOffset - 1) / 7) + 1,
            resWeek, resYear;

        if (week < 1) {
            resYear = mom.year() - 1;
            resWeek = week + weeksInYear(resYear, dow, doy);
        } else if (week > weeksInYear(mom.year(), dow, doy)) {
            resWeek = week - weeksInYear(mom.year(), dow, doy);
            resYear = mom.year() + 1;
        } else {
            resYear = mom.year();
            resWeek = week;
        }

        return {
            week: resWeek,
            year: resYear
        };
    }

    function weeksInYear(year, dow, doy) {
        var weekOffset = firstWeekOffset(year, dow, doy),
            weekOffsetNext = firstWeekOffset(year + 1, dow, doy);
        return (daysInYear(year) - weekOffset + weekOffsetNext) / 7;
    }

    // FORMATTING

    addFormatToken('w', ['ww', 2], 'wo', 'week');
    addFormatToken('W', ['WW', 2], 'Wo', 'isoWeek');

    // ALIASES

    addUnitAlias('week', 'w');
    addUnitAlias('isoWeek', 'W');

    // PRIORITIES

    addUnitPriority('week', 5);
    addUnitPriority('isoWeek', 5);

    // PARSING

    addRegexToken('w',  match1to2);
    addRegexToken('ww', match1to2, match2);
    addRegexToken('W',  match1to2);
    addRegexToken('WW', match1to2, match2);

    addWeekParseToken(['w', 'ww', 'W', 'WW'], function (input, week, config, token) {
        week[token.substr(0, 1)] = toInt(input);
    });

    // HELPERS

    // LOCALES

    function localeWeek (mom) {
        return weekOfYear(mom, this._week.dow, this._week.doy).week;
    }

    var defaultLocaleWeek = {
        dow : 0, // Sunday is the first day of the week.
        doy : 6  // The week that contains Jan 6th is the first week of the year.
    };

    function localeFirstDayOfWeek () {
        return this._week.dow;
    }

    function localeFirstDayOfYear () {
        return this._week.doy;
    }

    // MOMENTS

    function getSetWeek (input) {
        var week = this.localeData().week(this);
        return input == null ? week : this.add((input - week) * 7, 'd');
    }

    function getSetISOWeek (input) {
        var week = weekOfYear(this, 1, 4).week;
        return input == null ? week : this.add((input - week) * 7, 'd');
    }

    // FORMATTING

    addFormatToken('d', 0, 'do', 'day');

    addFormatToken('dd', 0, 0, function (format) {
        return this.localeData().weekdaysMin(this, format);
    });

    addFormatToken('ddd', 0, 0, function (format) {
        return this.localeData().weekdaysShort(this, format);
    });

    addFormatToken('dddd', 0, 0, function (format) {
        return this.localeData().weekdays(this, format);
    });

    addFormatToken('e', 0, 0, 'weekday');
    addFormatToken('E', 0, 0, 'isoWeekday');

    // ALIASES

    addUnitAlias('day', 'd');
    addUnitAlias('weekday', 'e');
    addUnitAlias('isoWeekday', 'E');

    // PRIORITY
    addUnitPriority('day', 11);
    addUnitPriority('weekday', 11);
    addUnitPriority('isoWeekday', 11);

    // PARSING

    addRegexToken('d',    match1to2);
    addRegexToken('e',    match1to2);
    addRegexToken('E',    match1to2);
    addRegexToken('dd',   function (isStrict, locale) {
        return locale.weekdaysMinRegex(isStrict);
    });
    addRegexToken('ddd',   function (isStrict, locale) {
        return locale.weekdaysShortRegex(isStrict);
    });
    addRegexToken('dddd',   function (isStrict, locale) {
        return locale.weekdaysRegex(isStrict);
    });

    addWeekParseToken(['dd', 'ddd', 'dddd'], function (input, week, config, token) {
        var weekday = config._locale.weekdaysParse(input, token, config._strict);
        // if we didn't get a weekday name, mark the date as invalid
        if (weekday != null) {
            week.d = weekday;
        } else {
            getParsingFlags(config).invalidWeekday = input;
        }
    });

    addWeekParseToken(['d', 'e', 'E'], function (input, week, config, token) {
        week[token] = toInt(input);
    });

    // HELPERS

    function parseWeekday(input, locale) {
        if (typeof input !== 'string') {
            return input;
        }

        if (!isNaN(input)) {
            return parseInt(input, 10);
        }

        input = locale.weekdaysParse(input);
        if (typeof input === 'number') {
            return input;
        }

        return null;
    }

    function parseIsoWeekday(input, locale) {
        if (typeof input === 'string') {
            return locale.weekdaysParse(input) % 7 || 7;
        }
        return isNaN(input) ? null : input;
    }

    // LOCALES
    function shiftWeekdays (ws, n) {
        return ws.slice(n, 7).concat(ws.slice(0, n));
    }

    var defaultLocaleWeekdays = 'Sunday_Monday_Tuesday_Wednesday_Thursday_Friday_Saturday'.split('_');
    function localeWeekdays (m, format) {
        var weekdays = isArray(this._weekdays) ? this._weekdays :
            this._weekdays[(m && m !== true && this._weekdays.isFormat.test(format)) ? 'format' : 'standalone'];
        return (m === true) ? shiftWeekdays(weekdays, this._week.dow)
            : (m) ? weekdays[m.day()] : weekdays;
    }

    var defaultLocaleWeekdaysShort = 'Sun_Mon_Tue_Wed_Thu_Fri_Sat'.split('_');
    function localeWeekdaysShort (m) {
        return (m === true) ? shiftWeekdays(this._weekdaysShort, this._week.dow)
            : (m) ? this._weekdaysShort[m.day()] : this._weekdaysShort;
    }

    var defaultLocaleWeekdaysMin = 'Su_Mo_Tu_We_Th_Fr_Sa'.split('_');
    function localeWeekdaysMin (m) {
        return (m === true) ? shiftWeekdays(this._weekdaysMin, this._week.dow)
            : (m) ? this._weekdaysMin[m.day()] : this._weekdaysMin;
    }

    function handleStrictParse$1(weekdayName, format, strict) {
        var i, ii, mom, llc = weekdayName.toLocaleLowerCase();
        if (!this._weekdaysParse) {
            this._weekdaysParse = [];
            this._shortWeekdaysParse = [];
            this._minWeekdaysParse = [];

            for (i = 0; i < 7; ++i) {
                mom = createUTC([2000, 1]).day(i);
                this._minWeekdaysParse[i] = this.weekdaysMin(mom, '').toLocaleLowerCase();
                this._shortWeekdaysParse[i] = this.weekdaysShort(mom, '').toLocaleLowerCase();
                this._weekdaysParse[i] = this.weekdays(mom, '').toLocaleLowerCase();
            }
        }

        if (strict) {
            if (format === 'dddd') {
                ii = indexOf.call(this._weekdaysParse, llc);
                return ii !== -1 ? ii : null;
            } else if (format === 'ddd') {
                ii = indexOf.call(this._shortWeekdaysParse, llc);
                return ii !== -1 ? ii : null;
            } else {
                ii = indexOf.call(this._minWeekdaysParse, llc);
                return ii !== -1 ? ii : null;
            }
        } else {
            if (format === 'dddd') {
                ii = indexOf.call(this._weekdaysParse, llc);
                if (ii !== -1) {
                    return ii;
                }
                ii = indexOf.call(this._shortWeekdaysParse, llc);
                if (ii !== -1) {
                    return ii;
                }
                ii = indexOf.call(this._minWeekdaysParse, llc);
                return ii !== -1 ? ii : null;
            } else if (format === 'ddd') {
                ii = indexOf.call(this._shortWeekdaysParse, llc);
                if (ii !== -1) {
                    return ii;
                }
                ii = indexOf.call(this._weekdaysParse, llc);
                if (ii !== -1) {
                    return ii;
                }
                ii = indexOf.call(this._minWeekdaysParse, llc);
                return ii !== -1 ? ii : null;
            } else {
                ii = indexOf.call(this._minWeekdaysParse, llc);
                if (ii !== -1) {
                    return ii;
                }
                ii = indexOf.call(this._weekdaysParse, llc);
                if (ii !== -1) {
                    return ii;
                }
                ii = indexOf.call(this._shortWeekdaysParse, llc);
                return ii !== -1 ? ii : null;
            }
        }
    }