index.js

                        'See http://momentjs.com/guides/#/warnings/define-locale/ for more info.'
                );
                parentConfig = locales[name]._config;
            } else if (config.parentLocale != null) {
                if (locales[config.parentLocale] != null) {
                    parentConfig = locales[config.parentLocale]._config;
                } else {
                    locale = loadLocale(config.parentLocale);
                    if (locale != null) {
                        parentConfig = locale._config;
                    } else {
                        if (!localeFamilies[config.parentLocale]) {
                            localeFamilies[config.parentLocale] = [];
                        }
                        localeFamilies[config.parentLocale].push({
                            name: name,
                            config: config,
                        });
                        return null;
                    }
                }
            }
            locales[name] = new Locale(mergeConfigs(parentConfig, config));

            if (localeFamilies[name]) {
                localeFamilies[name].forEach(function (x) {
                    defineLocale(x.name, x.config);
                });
            }

            // backwards compat for now: also set the locale
            // make sure we set the locale AFTER all child locales have been
            // created, so we won't end up with the child locale set.
            getSetGlobalLocale(name);

            return locales[name];
        } else {
            // useful for testing
            delete locales[name];
            return null;
        }
    }

    function updateLocale(name, config) {
        if (config != null) {
            var locale,
                tmpLocale,
                parentConfig = baseConfig;

            if (locales[name] != null && locales[name].parentLocale != null) {
                // Update existing child locale in-place to avoid memory-leaks
                locales[name].set(mergeConfigs(locales[name]._config, config));
            } else {
                // MERGE
                tmpLocale = loadLocale(name);
                if (tmpLocale != null) {
                    parentConfig = tmpLocale._config;
                }
                config = mergeConfigs(parentConfig, config);
                if (tmpLocale == null) {
                    // updateLocale is called for creating a new locale
                    // Set abbr so it will have a name (getters return
                    // undefined otherwise).
                    config.abbr = name;
                }
                locale = new Locale(config);
                locale.parentLocale = locales[name];
                locales[name] = locale;
            }

            // backwards compat for now: also set the locale
            getSetGlobalLocale(name);
        } else {
            // pass null for config to unupdate, useful for tests
            if (locales[name] != null) {
                if (locales[name].parentLocale != null) {
                    locales[name] = locales[name].parentLocale;
                    if (name === getSetGlobalLocale()) {
                        getSetGlobalLocale(name);
                    }
                } else if (locales[name] != null) {
                    delete locales[name];
                }
            }
        }
        return locales[name];
    }

    // returns locale data
    function getLocale(key) {
        var locale;

        if (key && key._locale && key._locale._abbr) {
            key = key._locale._abbr;
        }

        if (!key) {
            return globalLocale;
        }

        if (!isArray(key)) {
            //short-circuit everything else
            locale = loadLocale(key);
            if (locale) {
                return locale;
            }
            key = [key];
        }

        return chooseLocale(key);
    }

    function listLocales() {
        return keys(locales);
    }

    function checkOverflow(m) {
        var overflow,
            a = m._a;

        if (a && getParsingFlags(m).overflow === -2) {
            overflow =
                a[MONTH] < 0 || a[MONTH] > 11
                    ? MONTH
                    : a[DATE] < 1 || a[DATE] > daysInMonth(a[YEAR], a[MONTH])
                    ? DATE
                    : a[HOUR] < 0 ||
                      a[HOUR] > 24 ||
                      (a[HOUR] === 24 &&
                          (a[MINUTE] !== 0 ||
                              a[SECOND] !== 0 ||
                              a[MILLISECOND] !== 0))
                    ? HOUR
                    : a[MINUTE] < 0 || a[MINUTE] > 59
                    ? MINUTE
                    : a[SECOND] < 0 || a[SECOND] > 59
                    ? SECOND
                    : a[MILLISECOND] < 0 || a[MILLISECOND] > 999
                    ? MILLISECOND
                    : -1;

            if (
                getParsingFlags(m)._overflowDayOfYear &&
                (overflow < YEAR || overflow > DATE)
            ) {
                overflow = DATE;
            }
            if (getParsingFlags(m)._overflowWeeks && overflow === -1) {
                overflow = WEEK;
            }
            if (getParsingFlags(m)._overflowWeekday && overflow === -1) {
                overflow = WEEKDAY;
            }

            getParsingFlags(m).overflow = overflow;
        }

        return m;
    }

    // iso 8601 regex
    // 0000-00-00 0000-W00 or 0000-W00-0 + T + 00 or 00:00 or 00:00:00 or 00:00:00.000 + +00:00 or +0000 or +00)
    var extendedIsoRegex = /^\s*((?:[+-]\d{6}|\d{4})-(?:\d\d-\d\d|W\d\d-\d|W\d\d|\d\d\d|\d\d))(?:(T| )(\d\d(?::\d\d(?::\d\d(?:[.,]\d+)?)?)?)([+-]\d\d(?::?\d\d)?|\s*Z)?)?$/,
        basicIsoRegex = /^\s*((?:[+-]\d{6}|\d{4})(?:\d\d\d\d|W\d\d\d|W\d\d|\d\d\d|\d\d|))(?:(T| )(\d\d(?:\d\d(?:\d\d(?:[.,]\d+)?)?)?)([+-]\d\d(?::?\d\d)?|\s*Z)?)?$/,
        tzRegex = /Z|[+-]\d\d(?::?\d\d)?/,
        isoDates = [
            ['YYYYYY-MM-DD', /[+-]\d{6}-\d\d-\d\d/],
            ['YYYY-MM-DD', /\d{4}-\d\d-\d\d/],
            ['GGGG-[W]WW-E', /\d{4}-W\d\d-\d/],
            ['GGGG-[W]WW', /\d{4}-W\d\d/, false],
            ['YYYY-DDD', /\d{4}-\d{3}/],
            ['YYYY-MM', /\d{4}-\d\d/, false],
            ['YYYYYYMMDD', /[+-]\d{10}/],
            ['YYYYMMDD', /\d{8}/],
            ['GGGG[W]WWE', /\d{4}W\d{3}/],
            ['GGGG[W]WW', /\d{4}W\d{2}/, false],
            ['YYYYDDD', /\d{7}/],
            ['YYYYMM', /\d{6}/, false],
            ['YYYY', /\d{4}/, false],
        ],
        // iso time formats and regexes
        isoTimes = [
            ['HH:mm:ss.SSSS', /\d\d:\d\d:\d\d\.\d+/],
            ['HH:mm:ss,SSSS', /\d\d:\d\d:\d\d,\d+/],
            ['HH:mm:ss', /\d\d:\d\d:\d\d/],
            ['HH:mm', /\d\d:\d\d/],
            ['HHmmss.SSSS', /\d\d\d\d\d\d\.\d+/],
            ['HHmmss,SSSS', /\d\d\d\d\d\d,\d+/],
            ['HHmmss', /\d\d\d\d\d\d/],
            ['HHmm', /\d\d\d\d/],
            ['HH', /\d\d/],
        ],
        aspNetJsonRegex = /^\/?Date\((-?\d+)/i,
        // RFC 2822 regex: For details see https://tools.ietf.org/html/rfc2822#section-3.3
        rfc2822 = /^(?:(Mon|Tue|Wed|Thu|Fri|Sat|Sun),?\s)?(\d{1,2})\s(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s(\d{2,4})\s(\d\d):(\d\d)(?::(\d\d))?\s(?:(UT|GMT|[ECMP][SD]T)|([Zz])|([+-]\d{4}))$/,
        obsOffsets = {
            UT: 0,
            GMT: 0,
            EDT: -4 * 60,
            EST: -5 * 60,
            CDT: -5 * 60,
            CST: -6 * 60,
            MDT: -6 * 60,
            MST: -7 * 60,
            PDT: -7 * 60,
            PST: -8 * 60,
        };

    // date from iso format
    function configFromISO(config) {
        var i,
            l,
            string = config._i,
            match = extendedIsoRegex.exec(string) || basicIsoRegex.exec(string),
            allowTime,
            dateFormat,
            timeFormat,
            tzFormat;

        if (match) {
            getParsingFlags(config).iso = true;

            for (i = 0, l = isoDates.length; i < l; i++) {
                if (isoDates[i][1].exec(match[1])) {
                    dateFormat = isoDates[i][0];
                    allowTime = isoDates[i][2] !== false;
                    break;
                }
            }
            if (dateFormat == null) {
                config._isValid = false;
                return;
            }
            if (match[3]) {
                for (i = 0, l = isoTimes.length; i < l; i++) {
                    if (isoTimes[i][1].exec(match[3])) {
                        // match[2] should be 'T' or space
                        timeFormat = (match[2] || ' ') + isoTimes[i][0];
                        break;
                    }
                }
                if (timeFormat == null) {
                    config._isValid = false;
                    return;
                }
            }
            if (!allowTime && timeFormat != null) {
                config._isValid = false;
                return;
            }
            if (match[4]) {
                if (tzRegex.exec(match[4])) {
                    tzFormat = 'Z';
                } else {
                    config._isValid = false;
                    return;
                }
            }
            config._f = dateFormat + (timeFormat || '') + (tzFormat || '');
            configFromStringAndFormat(config);
        } else {
            config._isValid = false;
        }
    }

    function extractFromRFC2822Strings(
        yearStr,
        monthStr,
        dayStr,
        hourStr,
        minuteStr,
        secondStr
    ) {
        var result = [
            untruncateYear(yearStr),
            defaultLocaleMonthsShort.indexOf(monthStr),
            parseInt(dayStr, 10),
            parseInt(hourStr, 10),
            parseInt(minuteStr, 10),
        ];

        if (secondStr) {
            result.push(parseInt(secondStr, 10));
        }

        return result;
    }

    function untruncateYear(yearStr) {
        var year = parseInt(yearStr, 10);
        if (year <= 49) {
            return 2000 + year;
        } else if (year <= 999) {
            return 1900 + year;
        }
        return year;
    }

    function preprocessRFC2822(s) {
        // Remove comments and folding whitespace and replace multiple-spaces with a single space
        return s
            .replace(/\([^)]*\)|[\n\t]/g, ' ')
            .replace(/(\s\s+)/g, ' ')
            .replace(/^\s\s*/, '')
            .replace(/\s\s*$/, '');
    }

    function checkWeekday(weekdayStr, parsedInput, config) {
        if (weekdayStr) {
            // TODO: Replace the vanilla JS Date object with an independent day-of-week check.
            var weekdayProvided = defaultLocaleWeekdaysShort.indexOf(weekdayStr),
                weekdayActual = new Date(
                    parsedInput[0],
                    parsedInput[1],
                    parsedInput[2]
                ).getDay();
            if (weekdayProvided !== weekdayActual) {
                getParsingFlags(config).weekdayMismatch = true;
                config._isValid = false;
                return false;
            }
        }
        return true;
    }

    function calculateOffset(obsOffset, militaryOffset, numOffset) {
        if (obsOffset) {
            return obsOffsets[obsOffset];
        } else if (militaryOffset) {
            // the only allowed military tz is Z
            return 0;
        } else {
            var hm = parseInt(numOffset, 10),
                m = hm % 100,
                h = (hm - m) / 100;
            return h * 60 + m;
        }
    }

    // date and time from ref 2822 format
    function configFromRFC2822(config) {
        var match = rfc2822.exec(preprocessRFC2822(config._i)),
            parsedArray;
        if (match) {
            parsedArray = extractFromRFC2822Strings(
                match[4],
                match[3],
                match[2],
                match[5],
                match[6],
                match[7]
            );
            if (!checkWeekday(match[1], parsedArray, config)) {
                return;
            }

            config._a = parsedArray;
            config._tzm = calculateOffset(match[8], match[9], match[10]);

            config._d = createUTCDate.apply(null, config._a);
            config._d.setUTCMinutes(config._d.getUTCMinutes() - config._tzm);

            getParsingFlags(config).rfc2822 = true;
        } else {
            config._isValid = false;
        }
    }

    // date from 1) ASP.NET, 2) ISO, 3) RFC 2822 formats, or 4) optional fallback if parsing isn't strict
    function configFromString(config) {
        var matched = aspNetJsonRegex.exec(config._i);
        if (matched !== null) {
            config._d = new Date(+matched[1]);
            return;
        }

        configFromISO(config);
        if (config._isValid === false) {
            delete config._isValid;
        } else {
            return;
        }

        configFromRFC2822(config);
        if (config._isValid === false) {
            delete config._isValid;
        } else {
            return;
        }

        if (config._strict) {
            config._isValid = false;
        } else {
            // Final attempt, use Input Fallback
            hooks.createFromInputFallback(config);
        }
    }

    hooks.createFromInputFallback = deprecate(
        'value provided is not in a recognized RFC2822 or ISO format. moment construction falls back to js Date(), ' +
            'which is not reliable across all browsers and versions. Non RFC2822/ISO date formats are ' +
            'discouraged. Please refer to http://momentjs.com/guides/#/warnings/js-date/ for more info.',
        function (config) {
            config._d = new Date(config._i + (config._useUTC ? ' UTC' : ''));
        }
    );

    // Pick the first defined of two or three arguments.
    function defaults(a, b, c) {
        if (a != null) {
            return a;
        }
        if (b != null) {
            return b;
        }
        return c;
    }

    function currentDateArray(config) {
        // hooks is actually the exported moment object
        var nowValue = new Date(hooks.now());
        if (config._useUTC) {
            return [
                nowValue.getUTCFullYear(),
                nowValue.getUTCMonth(),
                nowValue.getUTCDate(),
            ];
        }
        return [nowValue.getFullYear(), nowValue.getMonth(), nowValue.getDate()];
    }

    // convert an array to a date.
    // the array should mirror the parameters below
    // note: all values past the year are optional and will default to the lowest possible value.
    // [year, month, day , hour, minute, second, millisecond]
    function configFromArray(config) {
        var i,
            date,
            input = [],
            currentDate,
            expectedWeekday,
            yearToUse;

        if (config._d) {
            return;
        }

        currentDate = currentDateArray(config);

        //compute day of the year from weeks and weekdays
        if (config._w && config._a[DATE] == null && config._a[MONTH] == null) {
            dayOfYearFromWeekInfo(config);
        }

        //if the day of the year is set, figure out what it is
        if (config._dayOfYear != null) {
            yearToUse = defaults(config._a[YEAR], currentDate[YEAR]);

            if (
                config._dayOfYear > daysInYear(yearToUse) ||
                config._dayOfYear === 0
            ) {
                getParsingFlags(config)._overflowDayOfYear = true;
            }

            date = createUTCDate(yearToUse, 0, config._dayOfYear);
            config._a[MONTH] = date.getUTCMonth();
            config._a[DATE] = date.getUTCDate();
        }

        // Default to current date.
        // * if no year, month, day of month are given, default to today
        // * if day of month is given, default month and year
        // * if month is given, default only year
        // * if year is given, don't default anything
        for (i = 0; i < 3 && config._a[i] == null; ++i) {
            config._a[i] = input[i] = currentDate[i];
        }

        // Zero out whatever was not defaulted, including time
        for (; i < 7; i++) {
            config._a[i] = input[i] =
                config._a[i] == null ? (i === 2 ? 1 : 0) : config._a[i];
        }

        // Check for 24:00:00.000
        if (
            config._a[HOUR] === 24 &&
            config._a[MINUTE] === 0 &&
            config._a[SECOND] === 0 &&
            config._a[MILLISECOND] === 0
        ) {
            config._nextDay = true;
            config._a[HOUR] = 0;
        }

        config._d = (config._useUTC ? createUTCDate : createDate).apply(
            null,
            input
        );
        expectedWeekday = config._useUTC
            ? config._d.getUTCDay()
            : config._d.getDay();

        // Apply timezone offset from input. The actual utcOffset can be changed
        // with parseZone.
        if (config._tzm != null) {
            config._d.setUTCMinutes(config._d.getUTCMinutes() - config._tzm);
        }

        if (config._nextDay) {
            config._a[HOUR] = 24;
        }

        // check for mismatching day of week
        if (
            config._w &&
            typeof config._w.d !== 'undefined' &&
            config._w.d !== expectedWeekday
        ) {
            getParsingFlags(config).weekdayMismatch = true;
        }
    }

    function dayOfYearFromWeekInfo(config) {
        var w, weekYear, week, weekday, dow, doy, temp, weekdayOverflow, curWeek;

        w = config._w;
        if (w.GG != null || w.W != null || w.E != null) {
            dow = 1;
            doy = 4;

            // TODO: We need to take the current isoWeekYear, but that depends on
            // how we interpret now (local, utc, fixed offset). So create
            // a now version of current config (take local/utc/offset flags, and
            // create now).
            weekYear = defaults(
                w.GG,
                config._a[YEAR],
                weekOfYear(createLocal(), 1, 4).year
            );
            week = defaults(w.W, 1);
            weekday = defaults(w.E, 1);
            if (weekday < 1 || weekday > 7) {
                weekdayOverflow = true;
            }
        } else {
            dow = config._locale._week.dow;
            doy = config._locale._week.doy;

            curWeek = weekOfYear(createLocal(), dow, doy);

            weekYear = defaults(w.gg, config._a[YEAR], curWeek.year);

            // Default to current week.
            week = defaults(w.w, curWeek.week);

            if (w.d != null) {
                // weekday -- low day numbers are considered next week
                weekday = w.d;
                if (weekday < 0 || weekday > 6) {
                    weekdayOverflow = true;
                }
            } else if (w.e != null) {
                // local weekday -- counting starts from beginning of week
                weekday = w.e + dow;
                if (w.e < 0 || w.e > 6) {
                    weekdayOverflow = true;
                }
            } else {
                // default to beginning of week
                weekday = dow;
            }
        }
        if (week < 1 || week > weeksInYear(weekYear, dow, doy)) {
            getParsingFlags(config)._overflowWeeks = true;
        } else if (weekdayOverflow != null) {
            getParsingFlags(config)._overflowWeekday = true;
        } else {
            temp = dayOfYearFromWeeks(weekYear, week, weekday, dow, doy);
            config._a[YEAR] = temp.year;
            config._dayOfYear = temp.dayOfYear;
        }
    }

    // constant that refers to the ISO standard
    hooks.ISO_8601 = function () {};

    // constant that refers to the RFC 2822 form
    hooks.RFC_2822 = function () {};

    // date from string and format string
    function configFromStringAndFormat(config) {
        // TODO: Move this to another part of the creation flow to prevent circular deps
        if (config._f === hooks.ISO_8601) {
            configFromISO(config);
            return;
        }
        if (config._f === hooks.RFC_2822) {
            configFromRFC2822(config);
            return;
        }
        config._a = [];
        getParsingFlags(config).empty = true;

        // This array is used to make a Date, either with `new Date` or `Date.UTC`
        var string = '' + config._i,
            i,
            parsedInput,
            tokens,
            token,
            skipped,
            stringLength = string.length,
            totalParsedInputLength = 0,
            era;

        tokens =
            expandFormat(config._f, config._locale).match(formattingTokens) || [];

        for (i = 0; i < tokens.length; i++) {
            token = tokens[i];
            parsedInput = (string.match(getParseRegexForToken(token, config)) ||
                [])[0];
            if (parsedInput) {
                skipped = string.substr(0, string.indexOf(parsedInput));
                if (skipped.length > 0) {
                    getParsingFlags(config).unusedInput.push(skipped);
                }
                string = string.slice(
                    string.indexOf(parsedInput) + parsedInput.length
                );
                totalParsedInputLength += parsedInput.length;
            }
            // don't parse if it's not a known token
            if (formatTokenFunctions[token]) {
                if (parsedInput) {
                    getParsingFlags(config).empty = false;
                } else {
                    getParsingFlags(config).unusedTokens.push(token);
                }
                addTimeToArrayFromToken(token, parsedInput, config);
            } else if (config._strict && !parsedInput) {
                getParsingFlags(config).unusedTokens.push(token);
            }
        }

        // add remaining unparsed input length to the string
        getParsingFlags(config).charsLeftOver =
            stringLength - totalParsedInputLength;
        if (string.length > 0) {
            getParsingFlags(config).unusedInput.push(string);
        }

        // clear _12h flag if hour is <= 12
        if (
            config._a[HOUR] <= 12 &&
            getParsingFlags(config).bigHour === true &&
            config._a[HOUR] > 0
        ) {
            getParsingFlags(config).bigHour = undefined;
        }

        getParsingFlags(config).parsedDateParts = config._a.slice(0);
        getParsingFlags(config).meridiem = config._meridiem;
        // handle meridiem
        config._a[HOUR] = meridiemFixWrap(
            config._locale,
            config._a[HOUR],
            config._meridiem
        );

        // handle era
        era = getParsingFlags(config).era;
        if (era !== null) {
            config._a[YEAR] = config._locale.erasConvertYear(era, config._a[YEAR]);
        }

        configFromArray(config);
        checkOverflow(config);
    }

    function meridiemFixWrap(locale, hour, meridiem) {
        var isPm;

        if (meridiem == null) {
            // nothing to do
            return hour;
        }
        if (locale.meridiemHour != null) {
            return locale.meridiemHour(hour, meridiem);
        } else if (locale.isPM != null) {
            // Fallback
            isPm = locale.isPM(meridiem);
            if (isPm && hour < 12) {
                hour += 12;
            }
            if (!isPm && hour === 12) {
                hour = 0;
            }
            return hour;
        } else {
            // this is not supposed to happen
            return hour;
        }
    }

    // date from string and array of format strings
    function configFromStringAndArray(config) {
        var tempConfig,
            bestMoment,
            scoreToBeat,
            i,
            currentScore,
            validFormatFound,
            bestFormatIsValid = false;

        if (config._f.length === 0) {
            getParsingFlags(config).invalidFormat = true;
            config._d = new Date(NaN);
            return;
        }

        for (i = 0; i < config._f.length; i++) {
            currentScore = 0;
            validFormatFound = false;
            tempConfig = copyConfig({}, config);
            if (config._useUTC != null) {
                tempConfig._useUTC = config._useUTC;
            }
            tempConfig._f = config._f[i];
            configFromStringAndFormat(tempConfig);

            if (isValid(tempConfig)) {
                validFormatFound = true;
            }

            // if there is any input that was not parsed add a penalty for that format
            currentScore += getParsingFlags(tempConfig).charsLeftOver;

            //or tokens
            currentScore += getParsingFlags(tempConfig).unusedTokens.length * 10;

            getParsingFlags(tempConfig).score = currentScore;

            if (!bestFormatIsValid) {
                if (
                    scoreToBeat == null ||
                    currentScore < scoreToBeat ||
                    validFormatFound
                ) {
                    scoreToBeat = currentScore;
                    bestMoment = tempConfig;
                    if (validFormatFound) {
                        bestFormatIsValid = true;
                    }
                }
            } else {
                if (currentScore < scoreToBeat) {
                    scoreToBeat = currentScore;
                    bestMoment = tempConfig;
                }
            }
        }

        extend(config, bestMoment || tempConfig);
    }

    function configFromObject(config) {
        if (config._d) {
            return;
        }

        var i = normalizeObjectUnits(config._i),
            dayOrDate = i.day === undefined ? i.date : i.day;
        config._a = map(
            [i.year, i.month, dayOrDate, i.hour, i.minute, i.second, i.millisecond],
            function (obj) {
                return obj && parseInt(obj, 10);
            }
        );

        configFromArray(config);
    }

    function createFromConfig(config) {
        var res = new Moment(checkOverflow(prepareConfig(config)));
        if (res._nextDay) {
            // Adding is smart enough around DST
            res.add(1, 'd');
            res._nextDay = undefined;
        }

        return res;
    }

    function prepareConfig(config) {
        var input = config._i,
            format = config._f;

        config._locale = config._locale || getLocale(config._l);

        if (input === null || (format === undefined && input === '')) {
            return createInvalid({ nullInput: true });
        }

        if (typeof input === 'string') {
            config._i = input = config._locale.preparse(input);
        }

        if (isMoment(input)) {
            return new Moment(checkOverflow(input));
        } else if (isDate(input)) {
            config._d = input;
        } else if (isArray(format)) {
            configFromStringAndArray(config);
        } else if (format) {
            configFromStringAndFormat(config);
        } else {
            configFromInput(config);
        }

        if (!isValid(config)) {
            config._d = null;
        }

        return config;
    }

    function configFromInput(config) {
        var input = config._i;
        if (isUndefined(input)) {
            config._d = new Date(hooks.now());
        } else if (isDate(input)) {
            config._d = new Date(input.valueOf());
        } else if (typeof input === 'string') {
            configFromString(config);
        } else if (isArray(input)) {
            config._a = map(input.slice(0), function (obj) {
                return parseInt(obj, 10);
            });
            configFromArray(config);
        } else if (isObject(input)) {
            configFromObject(config);
        } else if (isNumber(input)) {
            // from milliseconds
            config._d = new Date(input);
        } else {
            hooks.createFromInputFallback(config);
        }
    }

    function createLocalOrUTC(input, format, locale, strict, isUTC) {
        var c = {};

        if (format === true || format === false) {
            strict = format;
            format = undefined;
        }

        if (locale === true || locale === false) {
            strict = locale;
            locale = undefined;
        }

        if (
            (isObject(input) && isObjectEmpty(input)) ||
            (isArray(input) && input.length === 0)
        ) {
            input = undefined;
        }
        // object construction must be done this way.
        // https://github.com/moment/moment/issues/1423
        c._isAMomentObject = true;
        c._useUTC = c._isUTC = isUTC;
        c._l = locale;
        c._i = input;
        c._f = format;
        c._strict = strict;

        return createFromConfig(c);
    }

    function createLocal(input, format, locale, strict) {
        return createLocalOrUTC(input, format, locale, strict, false);
    }

    var prototypeMin = deprecate(
            'moment().min is deprecated, use moment.max instead. http://momentjs.com/guides/#/warnings/min-max/',
            function () {
                var other = createLocal.apply(null, arguments);
                if (this.isValid() && other.isValid()) {
                    return other < this ? this : other;
                } else {
                    return createInvalid();
                }
            }
        ),
        prototypeMax = deprecate(
            'moment().max is deprecated, use moment.min instead. http://momentjs.com/guides/#/warnings/min-max/',
            function () {
                var other = createLocal.apply(null, arguments);
                if (this.isValid() && other.isValid()) {
                    return other > this ? this : other;
                } else {
                    return createInvalid();
                }
            }
        );

    // Pick a moment m from moments so that m[fn](other) is true for all
    // other. This relies on the function fn to be transitive.
    //
    // moments should either be an array of moment objects or an array, whose
    // first element is an array of moment objects.
    function pickBy(fn, moments) {
        var res, i;
        if (moments.length === 1 && isArray(moments[0])) {
            moments = moments[0];
        }
        if (!moments.length) {
            return createLocal();
        }
        res = moments[0];
        for (i = 1; i < moments.length; ++i) {
            if (!moments[i].isValid() || moments[i][fn](res)) {
                res = moments[i];
            }
        }
        return res;
    }

    // TODO: Use [].sort instead?
    function min() {
        var args = [].slice.call(arguments, 0);

        return pickBy('isBefore', args);
    }

    function max() {
        var args = [].slice.call(arguments, 0);

        return pickBy('isAfter', args);
    }

    var now = function () {
        return Date.now ? Date.now() : +new Date();
    };

    var ordering = [
        'year',
        'quarter',
        'month',
        'week',
        'day',
        'hour',
        'minute',
        'second',
        'millisecond',
    ];

    function isDurationValid(m) {
        var key,
            unitHasDecimal = false,
            i;
        for (key in m) {
            if (
                hasOwnProp(m, key) &&
                !(
                    indexOf.call(ordering, key) !== -1 &&
                    (m[key] == null || !isNaN(m[key]))
                )
            ) {
                return false;
            }
        }

        for (i = 0; i < ordering.length; ++i) {
            if (m[ordering[i]]) {
                if (unitHasDecimal) {
                    return false; // only allow non-integers for smallest unit
                }
                if (parseFloat(m[ordering[i]]) !== toInt(m[ordering[i]])) {
                    unitHasDecimal = true;
                }
            }
        }

        return true;
    }

    function isValid$1() {
        return this._isValid;
    }

    function createInvalid$1() {
        return createDuration(NaN);
    }

    function Duration(duration) {
        var normalizedInput = normalizeObjectUnits(duration),