moment_dart 0.4.2

A package that turns DateTime into human-readable format. An attempt to port moment.js to dart. Supports multiple localizations (en_US, ko_KO, mn_MN, de_DE, more to be added..)

A Moment.js inspired package.

Usage

Import the package

import "package:moment_dart/moment_dart.dart";

Create Moment instance

final Moment now = Moment.now();

final Moment epoch = Moment(DateTime.fromMicrosecondsSinceEpoch(0, isUtc: true));

final Moment derived = DateTime(2003,06,01).toMoment();

Enjoy!

final Moment moment = Moment.now() - Duration(days: 1); // May 14, 2022

moment.calendar(); // Yesterday

moment.fromNow(); // a day ago

// You can omit the prefix/suffix by setting the optional argument to true.
moment.fromNow(true); // a day

moment.from(moment - Duration(days: 365)); // a year ago

/// Unmatched strings will be left as is.
moment.format("YYYY년 MMMM Do dddd hh:mma"); // 2022년 May 14 Saturday 08:09pm

Change localization

When localization is omitted, it defaults to English (United States)

final Moment hangulday = Moment(DateTime(2022,10,9), localization: MomentLocalizations.ko());

hangulday.format("ll"); // 2022년 10월 9
hangulday.format("LL"); // 2022년 10월 9

You can also take advantage of localization, as it's kinda the main character

final MomentLocalization localization = MomentLocalizations.enUS();

localization.relative(const Duration(seconds: 2)); //in a few seconds
localization.weekdayName(yesterday.weekday); // "Monday"

Formatting

  /// All non-token characters will be left as is
  moment.format("YYYY년 MMM Do ddd A hh:mm"); // 2022년 6월 1일 수요일 오후 02:44

Tokens:

Type	Token	Examples	Description
Month	M	1 2 ... 11 12
	Mo	1st 2nd ... 11th 12th
	MM	01 02 ... 11 12
	MMM	Jan Feb ... Nov Dec
	MMMM	January February ... November December
Quarter of year	Q	1 2 3 4
	Qo	1st 2nd 3rd 4th
Day of month	D	1 2 ... 30 31
	Do	1st 2nd ... 30th 31st
	DD	01 02 ... 30 31
Day of year	DDD	1 2 ... 364 365
	DDDo	1st 2nd ... 364th 365th
	DDDD	001 002 ... 364 365
Day of week	d	1 2 ...6 7	Moment.js uses `0-6`. However, we'll be using `1-7` to be in accordance with [DateTime]
	d_o	1st 2nd ... 6th 7th	"do" is Dart language keyword
	dd	Mo Tu ... Sa Su
	ddd	Mon Tue ... Sat Sun
	dddd	Monday ... Saturday Sunday
Day of week (ISO)	e	1 2 ... 6 7
Week of year (ISO)	w	1 2 ... 52 53
	wo	1st 2nd ... 52nd 53rd
	ww	01 02 ... 52 53
Year	YY	70 71 ... 29 30
	YYYY	1970 1971 ... 2029 2030
Era Year	y	1 2 ... 2020 ...
Era	NN	BC AD	Abbr era name
	NNNN	Before Christ, Anno Domini	Full era name
	NNNNN	BC AD	Narrow era name
Week year	gg	70 71 ... 29 30
	gggg	1970 1971 ... 2029 2030
AM/PM	A	AM PM	UPPERCASE
	a	am pm	lowercase
Hour	H	0 1 ... 22 23
	HH	00 01 ... 22 23
	h	1 2 ... 11 12
	hh	01 02 ... 11 12
	k	1 2 ... 23 24
	kk	01 02 ... 23 24
Minute	m	0 1 ... 58 59
	mm	00 01 ... 58 59
Second	s	0 1 ... 58 59
	ss	00 01 ... 58 59
Fractional second	S	0 1 ... 8 9
	SS	00 01 ... 98 99
	SSS	000 001 ... 998 999
	SSSS	0000 0001 ... 9998,9999
	SSSSS	00000 00001 ... 99998,99999
	SSSSSS	000000 000001 ... 999998,999999
Timezone	Z	-07:00 -06:00 ... +06:00 +07:00
	ZZ	-0700 -0600 ... +0600 +0700
Timezone name	ZZZ		Returns [DateTime.timeZoneName], result may not be consistent across platforms
Unix timestamp in seconds	X	1654063960
Unix timestamp	x	1654063974620
Localization Defaults	l	9/4/1986	Date (in local format, shorter)
	L	09/04/1986	Date (in local format)
	ll	Sep 4 1986	Month name, day of month, year (shorter)
	LL	September 04 1986	Month name, day of month, year
	lll	Sep 4 1986 8:30 PM	Month name, day of month, year, time
	LLL	September 04 1986 8:30 PM	Month name, day of month, year, time
	llll	Thu, Sep 4 1986 8:30 PM	Day of week, month name, day of month, year, time (shorter)
	LLLL	Thursday, September 04 1986 8:30 PM	Day of week, month name, day of month, year, time
	LT	8:30 PM	Time (without seconds)
	LTS	8:30:00 PM	Time (with seconds)

Moment introduces a extension with few helpful functions.

Can be called on Moment or DateTime instance

final DateTime date = DateTime(2022,03,29);

//Returns the ISO Week number of the year
//
// [1,2,3,...,52,53]
date.week == 13; // true

// Returns the year according to ISO Week
date.weekYear == 2022; // true

// Returns the quarter of the year. [][Jan,Feb,Mar][Apr,May,Jun][Jul,Aug,Sep][Oct,Nov,Dec]
//
// [1,2,3,4]
date.quarter == 1; // true

// Returns if the [year] is leap year
date.isLeapYear == false; // true

/// Returns ordinal day of the year
/// 
/// [1,2,3,...,365,366]
date.dayOfYear == 88; // true

Read more about ISO week on Wikipedia

Creating your own Localzation

First, extend the Localization abstract class.

Almost everything is declared as function, so you can freely achieve the unique features of your language.

I highly recommend copying one of the existing implementations, and work on it!

  CatLanguage extends MomentLocalization {
    @override
    String relative(Duration duration, [bool dropPrefixOrSuffix = false]) => "a two meow ago";

    @override
    String weekdayName(int i) => "Meowday #$i";

    @override
    String calendar(Moment moment, {Moment? reference, bool weekStartOnSunday = false, bool omitHours = false}) => "Last Meowday";

    /// Please refer to the [FormatterToken] enum for details.
    /// 
    /// It contains almost all of the tokens mentioned in https://momentjs.com/docs/#/parsing/string-format/
    Map<FormatterToken, FormatterTokenFn?> formats() => {};

    @override
    String languageCodeISO() => "meow";

    @override
    String endonym() => "Meow-meow meow";

    @override
    String locale() => "meow";

    @override
    String languageNameInEnglish() => "Cat tongue";
  }

Available Localization classes:

Localizations are classes that extend MomentLocalization

• LocalizationEnUs (English - United States) [en_US]
• LocalizationKorean (Korean) [ko]
• LocalizationGermanStandard (German) [de_DE]
• LocalizationMongolianCyrillic (Mongolian) [mn]
  • LocalizationMongolianTraditional (Mongolian) [mn]
  • LocalizationMongolianTraditionalNumbers (Uses traditional Mongolian numbers)

TODO

• Add more localizations
• String escaper in Moment.format()
• Implement parsing string produced from Moment.format($)