private void initializeDateTimeFormat()

in lib/Platform/Intl/java/com/facebook/hermes/intl/DateTimeFormat.java [170:401]
192 lines of code
17 McCabe index (conditional complexity)

  private void initializeDateTimeFormat(List<String> locales, Map<String, Object> inOptions)
      throws JSRangeErrorException {

    List<String> relevantExtensionKeys = Arrays.asList("ca", "nu", "hc");

    // 2
    Object options = ToDateTimeOptions(inOptions, "any", "date");

    // 3
    Object opt = JSObjects.newObject();

    // 4,5,
    Object matcher =
        OptionHelpers.GetOption(
            options,
            Constants.LOCALEMATCHER,
            OptionHelpers.OptionType.STRING,
            Constants.LOCALEMATCHER_POSSIBLE_VALUES,
            Constants.LOCALEMATCHER_BESTFIT);
    JSObjects.Put(opt, "localeMatcher", matcher);

    // 6 - 8
    Object calendar =
        OptionHelpers.GetOption(
            options,
            "calendar",
            OptionHelpers.OptionType.STRING,
            JSObjects.Undefined(),
            JSObjects.Undefined());
    if (!JSObjects.isUndefined(calendar)) {
      if (!isLocaleIdType(JSObjects.getJavaString(calendar)))
        throw new JSRangeErrorException("Invalid calendar option !");
    }
    JSObjects.Put(opt, "ca", calendar);

    // 9 - 11
    Object numberingSystem =
        OptionHelpers.GetOption(
            options,
            "numberingSystem",
            OptionHelpers.OptionType.STRING,
            JSObjects.Undefined(),
            JSObjects.Undefined());
    if (!JSObjects.isUndefined(numberingSystem)) {
      if (!isLocaleIdType(JSObjects.getJavaString(numberingSystem)))
        throw new JSRangeErrorException("Invalid numbering system !");
    }
    JSObjects.Put(opt, "nu", numberingSystem);

    // 12 - 15
    Object hour12 =
        OptionHelpers.GetOption(
            options,
            "hour12",
            OptionHelpers.OptionType.BOOLEAN,
            JSObjects.Undefined(),
            JSObjects.Undefined());
    Object hourCycle =
        OptionHelpers.GetOption(
            options,
            "hourCycle",
            OptionHelpers.OptionType.STRING,
            new String[] {"h11", "h12", "h23", "h24"},
            JSObjects.Undefined());

    if (!JSObjects.isUndefined(hour12)) hourCycle = JSObjects.Null();

    JSObjects.Put(opt, "hc", hourCycle);

    // 16 - 23
    HashMap<String, Object> r = LocaleResolver.resolveLocale(locales, opt, relevantExtensionKeys);

    mResolvedLocaleObject = (ILocaleObject<?>) JSObjects.getJavaMap(r).get("locale");
    mResolvedLocaleObjectForResolvedOptions = mResolvedLocaleObject.cloneObject();

    Object calendarResolved = JSObjects.Get(r, "ca");
    if (!JSObjects.isNull(calendarResolved)) {
      useDefaultCalendar = false;
      mCalendar = JSObjects.getJavaString(calendarResolved);
    } else {
      useDefaultCalendar = true;
      mCalendar = mPlatformDateTimeFormatter.getDefaultCalendarName(mResolvedLocaleObject);
    }

    Object numeringSystemResolved = JSObjects.Get(r, "nu");
    if (!JSObjects.isNull(numeringSystemResolved)) {
      useDefaultNumberSystem = false;
      mNumberingSystem = JSObjects.getJavaString(numeringSystemResolved);
    } else {
      useDefaultNumberSystem = true;
      mNumberingSystem =
          mPlatformDateTimeFormatter.getDefaultNumberingSystem(mResolvedLocaleObject);
    }

    Object hourCycleResolved = JSObjects.Get(r, "hc");

    // 24 - 27
    Object timeZone = JSObjects.Get(options, "timeZone");
    if (JSObjects.isUndefined(timeZone)) {
      timeZone = DefaultTimeZone();
    } else {
      timeZone = normalizeTimeZone(timeZone.toString());
    }
    mTimeZone = timeZone;

    // 28 - 34
    Object formatMatcher =
        OptionHelpers.GetOption(
            options,
            "formatMatcher",
            OptionHelpers.OptionType.STRING,
            new String[] {"basic", "best fit"},
            "best fit");
    mFormatMatcher =
        OptionHelpers.searchEnum(
            IPlatformDateTimeFormatter.FormatMatcher.class, JSObjects.getJavaString(formatMatcher));

    // 29, 35
    Object weekDay =
        OptionHelpers.GetOption(
            options,
            "weekday",
            OptionHelpers.OptionType.STRING,
            new String[] {"long", "short", "narrow"},
            JSObjects.Undefined());
    mWeekDay = OptionHelpers.searchEnum(IPlatformDateTimeFormatter.WeekDay.class, weekDay);

    Object era =
        OptionHelpers.GetOption(
            options,
            "era",
            OptionHelpers.OptionType.STRING,
            new String[] {"long", "short", "narrow"},
            JSObjects.Undefined());
    mEra = OptionHelpers.searchEnum(IPlatformDateTimeFormatter.Era.class, era);

    Object year =
        OptionHelpers.GetOption(
            options,
            "year",
            OptionHelpers.OptionType.STRING,
            new String[] {"numeric", "2-digit"},
            JSObjects.Undefined());
    mYear = OptionHelpers.searchEnum(IPlatformDateTimeFormatter.Year.class, year);

    Object month =
        OptionHelpers.GetOption(
            options,
            "month",
            OptionHelpers.OptionType.STRING,
            new String[] {"numeric", "2-digit", "long", "short", "narrow"},
            JSObjects.Undefined());
    mMonth = OptionHelpers.searchEnum(IPlatformDateTimeFormatter.Month.class, month);

    Object day =
        OptionHelpers.GetOption(
            options,
            "day",
            OptionHelpers.OptionType.STRING,
            new String[] {"numeric", "2-digit"},
            JSObjects.Undefined());
    mDay = OptionHelpers.searchEnum(IPlatformDateTimeFormatter.Day.class, day);

    Object hour =
        OptionHelpers.GetOption(
            options,
            "hour",
            OptionHelpers.OptionType.STRING,
            new String[] {"numeric", "2-digit"},
            JSObjects.Undefined());
    mHour = OptionHelpers.searchEnum(IPlatformDateTimeFormatter.Hour.class, hour);

    Object minute =
        OptionHelpers.GetOption(
            options,
            "minute",
            OptionHelpers.OptionType.STRING,
            new String[] {"numeric", "2-digit"},
            JSObjects.Undefined());
    mMinute = OptionHelpers.searchEnum(IPlatformDateTimeFormatter.Minute.class, minute);

    Object second =
        OptionHelpers.GetOption(
            options,
            "second",
            OptionHelpers.OptionType.STRING,
            new String[] {"numeric", "2-digit"},
            JSObjects.Undefined());
    mSecond = OptionHelpers.searchEnum(IPlatformDateTimeFormatter.Second.class, second);

    Object timeZoneName =
        OptionHelpers.GetOption(
            options,
            "timeZoneName",
            OptionHelpers.OptionType.STRING,
            new String[] {"long", "short"},
            JSObjects.Undefined());
    mTimeZoneName =
        OptionHelpers.searchEnum(IPlatformDateTimeFormatter.TimeZoneName.class, timeZoneName);

    // 36
    if (JSObjects.isUndefined(hour)) {
      mHourCycle = IPlatformDateTimeFormatter.HourCycle.UNDEFINED;
    } else {
      IPlatformDateTimeFormatter.HourCycle hcDefault =
          mPlatformDateTimeFormatter.getDefaultHourCycle(mResolvedLocaleObject);
      IPlatformDateTimeFormatter.HourCycle hc;

      if (JSObjects.isNull(hourCycleResolved)) {
        hc = hcDefault;
      } else {
        hc =
            OptionHelpers.searchEnum(IPlatformDateTimeFormatter.HourCycle.class, hourCycleResolved);
      }

      if (!JSObjects.isUndefined(hour12)) {
        if (JSObjects.getJavaBoolean(hour12)) { // true
          if (hcDefault == IPlatformDateTimeFormatter.HourCycle.H11
              || hcDefault == IPlatformDateTimeFormatter.HourCycle.H23)
            hc = IPlatformDateTimeFormatter.HourCycle.H11;
          else hc = IPlatformDateTimeFormatter.HourCycle.H12;
        } else {
          if (hcDefault == IPlatformDateTimeFormatter.HourCycle.H11
              || hcDefault == IPlatformDateTimeFormatter.HourCycle.H23)
            hc = IPlatformDateTimeFormatter.HourCycle.H23;
          else hc = IPlatformDateTimeFormatter.HourCycle.H24;
        }
      }

      mHourCycle = hc;
    }
  }