Skip to main content
Version: 1.1.1

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 {

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",

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

String get endonym => "Meow!";

String get languageCode => "en";

String get languageNameInEnglish => "Meowlish!";

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

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"),

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

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 ... */

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

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

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

Map<FormatterToken, FormatterTokenFn?> overrideFormatters() => {
// From [EnglishLikeOrdinal] mixin
...formattersWithOrdinal, // Provided by mixin `Ordinal`
// From [MonthNames] mixin
...formattersForMonthNames, // Provided by mixin MonthNames

/* Other formatters */