Implementing localization

You can extend MomentLocalization class to implement localization for your own language. Majority of the functionalities are defined as methods, allowing developers to acheive unique features of their language.

Best way to implement a new localization is to copy en_US, or a localization that is similar to your language, then make modifications.

MomentLocalization relies heavily on Mixins

Example implementation

import 'package:moment_dart/src/formatters/token.dart';
import 'package:moment_dart/src/calendar.dart';
import 'package:moment_dart/src/localizations.dart';

class LocalizationEnMeowKC extends MomentLocalization {
  @override
  CalenderLocalizationData get calendarData => CalenderLocalizationData(
        keywords: CalenderLocalizationKeywords(
          at: (date, time) => "meow $time",
          lastWeekday: (weekday) => "Last meow $weekday",
          nextWeekday: (weekday) => weekday,
        ),
        relativeDayNames: {
          -1: "Yestermeow",
          0: "Meowday",
          1: "Tomeowow",
        },
      );

  @override
  String? get countryCode => "KC"; // Kingdom of Cats

  @override
  String get endonym => "Meow!";

  @override
  String get languageCode => "en";

  @override
  String get languageNameInEnglish => "Meowlish!";

  @override
  String get locale => "en_Meow_KC"; // You may want to override this one

  @override
  Map<FormatterToken, FormatterTokenFn?> overrideFormatters() => {
        // Localization aware formats - Highly recommend implementing these :)
        FormatterToken.L: (dateTime) => reformat(dateTime, "YYYY/MM/DD"),
        FormatterToken.l: (dateTime) => reformat(dateTime, "YYYY/M/D"),
        FormatterToken.LL: (dateTime) =>
            reformat(dateTime, "MMMM D, [meow] YYYY"),
        FormatterToken.ll: (dateTime) =>
            reformat(dateTime, "MMM D, [meow] YYYY"),
        FormatterToken.LLL: (dateTime) =>
            reformat(dateTime, "MMMM D, [meow] YYYY, HH:mm [meow!]"),
        FormatterToken.lll: (dateTime) =>
            reformat(dateTime, "MMM D, [meow] YYYY, HH:mm [meow!]"),
        FormatterToken.LLLL: (dateTime) =>
            reformat(dateTime, "dddd, MMMM D, [meow] YYYY, HH:mm [meow!]"),
        FormatterToken.llll: (dateTime) =>
            reformat(dateTime, "ddd, MMM D, [meow] YYYY, HH:mm [meow!]"),
        FormatterToken.LT: (dateTime) => reformat(dateTime, "HH:mm"),
        FormatterToken.LTS: (dateTime) => reformat(dateTime, "HH:mm:ss"),
      };

  @override
  String relative(Duration duration, [bool dropPrefixOrSuffix = false]) =>
      "(in) Meow $duration (ago)";

  @override
  Map<int, String> get weekdayName => {
        DateTime.monday: "Meowday #1",
        ...,
        DateTime.sunday: "Meowday #7",
      };
}

Example usage of mixins

class MewLocale extends MomentLocalization with Ordinal, MonthNames {
  /* ... folded code ... */

  @override
  Map<int, String> get monthNames => {
    DateTime.january: "Janmeow",
    ...,
    DateTime.december: "Decemeow",
  };

  @override
  Map<int, String> get monthNamesShort => monthNames.map((key, value) => MapEntry(key, value.substring(0,3)));

  @override
  String ordinalNumber(int n) => "meow $nº";

  @override
  Map<FormatterToken, FormatterTokenFn?> overrideFormatters() => {
        // From [EnglishLikeOrdinal] mixin
        ...formattersWithOrdinal, // Provided by mixin `Ordinal`
        // From [MonthNames] mixin
        ...formattersForMonthNames, // Provided by mixin MonthNames
        
        /* Other formatters */
      };
}