eslint-plugin-you-dont-need-momentjs

You don't (may not) need Moment.js

Moment.js is a fantastic time & date library with lots of great features and utilities. However, if you are working on a performance sensitive web application, it might cause a huge performance overhead because of its complex APIs and large bundle size.

Problems with Moment.js:

• It is highly based on OOP APIs, which makes it fail to work with tree-shaking, thus leading to a huge bundle size and performance issues.
• It is mutable and it causes bugs:
  • clone
  • How do I work around mutability in moment.js?
• Complex OOP API (which doubles mutability problem). Here is an example: https://github.com/moment/moment/blob/develop/src/test/moment/add_subtract.js#L244-L286 Moment.js allows to use a.subtract('ms', 50), a.subtract(50, 'ms') and even a.subtract('s', '50').

If you are not using timezone but only a few simple functions from moment.js, this might bloat your app, and therefore is considered overkill. dayjs has a smaller core and has very similar APIs so it makes it very easy to migrate. date-fns enables tree-shaking and other benefits so that it works great with React, Sinon.js, and webpack, etc. See https://github.com/moment/moment/issues/2373 for more ideas on why and how people switch from moment.js to other solutions.

Brief Comparison

Name	Size original/gzipped	Tree-shaking	Popularity (stars)	Methods richness	Pattern	Timezone Support	Locale
Moment.js	329K/69.6K	No	43.4k	High	OO	Good (moment-timezone)	123
Luxon	59.9K/17.2K	No	9k	High	OO	Good (Intl)	-
date-fns	78.4k/13.4k without tree-shaking	Yes	21.3k	High	Functional	Good (date-fns-tz)	64
dayjs	6.5k/2.6k without plugins	No	25.8k	High	OO	Not yet	130

Voice of Developers

Removed moment.js to replace with date-fns - build output reduced by 40%

—Jared Farago from webnode project.

Good library if you’re looking to replace Moment.js for one reason or another. Immutable too.

—Dan Abramov, Author of Redux and co-author of Create React App. Building tools for humans.

I strongly recommend using date-fns over Moment.js, it's has a nicer API and you can include only parts you need!

—Matija Marohnić, a design-savvy frontend developer from Croatia.

Just yesterday changed momentjs to this lib in out project. Cut the size of our js bundle almost in half 😱

—Sergey Petushkov, a javaScript developer from Moscow, Russia • Currently in Berlin, Germany.

ESLint Plugin

If you're using ESLint, you can install a plugin that will help you identify places in your codebase where you don't (may not) need Moment.js.

Install the plugin...

npm install --save-dev eslint-plugin-you-dont-need-momentjs

...then update your config

"extends" : ["plugin:you-dont-need-momentjs/recommended"],

Quick Links

Parse

1. String + Date Format
2. String + Time Format
3. String + Format + locale

Get + Set

1. Millisecond/Second/Minute/Hour
2. Date of Month
3. Day of Week
4. Day of Year
5. Week of Year
6. Days in Month
7. Weeks in Year
8. Maximum of the given dates
9. Minimum of the given dates

Manipulate

1. Add
2. Subtract
3. Start of Time
4. End of Time

Display

1. Format
2. Time from now
3. Time from X
4. Difference

Query

1. Is Before
2. Is Same
3. Is After
4. Is Between
5. Is Leap Year
6. Is a Date

Feature Parity

⚠️ Indicates other packages or work are needed. See individual functions above.

	Native	Luxon	date-fns	dayjs
Parse
String + Date Format	✅	✅	✅	✅
String + Time Format	✅	✅	✅	⚠️
String + Format + locale	❌	⚠️	✅	⚠️
Get + Set
Millisecond/Second/Minute/Hour	✅	✅	✅	✅
Date of Month	✅	✅	✅	✅
Day of Week	✅	✅	✅	✅
Day of Year	✅	✅	✅	✅
Week of Year	✅	✅	✅	⚠️
Days in Month	✅	✅	✅	✅
Weeks in Year	❌	❌	✅	⚠️
Maximum of the given dates	✅	✅	✅	⚠️
Minimum of the given dates	✅	✅	✅	⚠️
Manipulate
Add	✅	✅	✅	✅
Subtract	✅	✅	✅	✅
Start of Time	❌	✅	✅	✅
End of Time	✅	✅	✅	✅
Display
Format	❌	✅	✅	✅
Time from now	❌	❌	✅	⚠️
Time from X	❌	❌	✅	⚠️
Difference	✅	✅	✅	✅
Query
Is Before	✅	✅	✅	✅
Is Same	✅	✅	✅	✅
Is After	✅	✅	✅	✅
Is Between	❌	✅	✅	⚠️
Is Leap Year	✅	✅	✅	⚠️
Is a Date	✅	✅	✅	✅

Parse

String + Date Format

Return the date parsed from date string using the given format string.

// Moment.js
moment('12-25-1995', 'MM-DD-YYYY');
// => "1995-12-24T13:00:00.000Z"

// Native
const datePattern = /^(\d{2})-(\d{2})-(\d{4})$/;
const [, month, day, year] = datePattern.exec('12-25-1995');
new Date(`${month}, ${day} ${year}`);
// => "1995-12-24T13:00:00.000Z"

// date-fns
import parse from 'date-fns/parse';
parse('12-25-1995', 'MM-dd-yyyy', new Date());
// => "1995-12-24T13:00:00.000Z"

// dayjs
dayjs('12-25-1995');
// => "1995-12-24T13:00:00.000Z"

// luxon
DateTime.fromFormat('12-25-1995', 'MM-dd-yyyy').toJSDate();
// => "1995-12-24T13:00:00.000Z"

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String + Time Format

Return the date parsed from time string using the given format string.

// Moment.js
moment('2010-10-20 4:30', 'YYYY-MM-DD HH:mm');
// => "2010-10-19T17:30:00.000Z"

// Native
const datePattern = /^(\d{4})-(\d{2})-(\d{2})\s(\d{1,2}):(\d{2})$/;
const [, year, month, day, rawHour, min] = datePattern.exec('2010-10-20 4:30');
new Date(`${year}-${month}-${day}T${('0' + rawHour).slice(-2)}:${min}:00`);
// => "2010-10-19T17:30:00.000Z"

// date-fns
import parse from 'date-fns/parse';
parse('2010-10-20 4:30', 'yyyy-MM-dd H:mm', new Date());
// => "2010-10-19T17:30:00.000Z"

// dayjs ⚠️ requires customParseFormat plugin
import customParseFormat from 'dayjs/plugin/customParseFormat';
dayjs.extend(customParseFormat);
dayjs('2010-10-20 4:30', 'YYYY-MM-DD HH:mm');
// => "2010-10-19T17:30:00.000Z"

// luxon
DateTime.fromFormat('2010-10-20 4:30', 'yyyy-MM-dd H:mm').toJSDate();
// => "2010-10-19T17:30:00.000Z"

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String + Format + locale

Return the date parsed from string using the given format string and locale.

// Moment.js
moment('2012 mars', 'YYYY MMM', 'fr');
// => "2012-02-29T13:00:00.000Z"

// date-fns
import parse from 'date-fns/parse';
import fr from 'date-fns/locale/fr';
parse('2012 mars', 'yyyy MMMM', new Date(), { locale: fr });
// => "2012-02-29T13:00:00.000Z"

// dayjs ⚠️ requires customParseFormat plugin
import customParseFormat from 'dayjs/plugin/customParseFormat';
import 'dayjs/locale/fr';
dayjs.extend(customParseFormat);
dayjs('2012 mars', 'YYYY MMM', 'fr');
// => "2012-02-29T13:00:00.000Z"

// Luxon ❌ does not support Locale for node unless https://moment.github.io/luxon/docs/manual/install.html#node
DateTime.fromFormat('2012 mars', 'yyyy MMMM', { locale: 'fr' });
// => "2012-02-29T13:00:00.000Z"

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Get + Set

Millisecond / Second / Minute / Hour

Get the Millisecond/Second/Minute/Hour of the given date.

// Moment.js
moment().seconds();
// => 49
moment().hours();
// => 19

// Native
new Date().getSeconds();
// => 49
new Date().getHours();
// => 19

// date-fns
import getSeconds from 'date-fns/getSeconds';
import getHours from 'date-fns/getHours';
getSeconds(new Date());
// => 49
getHours(new Date());
// => 19

// dayjs
dayjs().second();
// => 49
dayjs().hour();
// => 19

// Luxon
DateTime.local().second;
// => 49
DateTime.local().hour;
// => 19

Performance tests

Library	Time
Moment	1500.703ms
Native	348.411ms
DateFns	520.670ms
DayJs	494.234ms
Luxon	1208.368ms

Set the Millisecond/Second/Minute/Hour of the given date.

// Moment.js
moment().seconds(30);
// => "2018-09-09T09:12:30.695Z"
moment().hours(13);
// => "2018-09-09T03:12:49.695Z"

// Native
new Date(new Date().setSeconds(30));
// => "2018-09-09T09:12:30.695Z"
new Date(new Date().setHours(13));
// => "2018-09-09T03:12:49.695Z"

// date-fns
import setSeconds from 'date-fns/setSeconds';
import setHours from 'date-fns/setHours';
setSeconds(new Date(), 30);
// => "2018-09-09T09:12:30.695Z"
setHours(new Date(), 13);
// => "2018-09-09T03:12:49.695Z"

// dayjs
dayjs().set('second', 30);
// => "2018-09-09T09:12:30.695Z"
dayjs().set('hour', 13);
// => "2018-09-09T03:12:49.695Z"

// luxon
DateTime.utc()
  .set({ second: 30 })
  .toJSDate();
// => "2018-09-09T09:12:30.695Z"
DateTime.utc()
  .set({ hour: 13 })
  .toJSDate();
// => "2018-09-09T03:12:49.695Z"

Performance tests

Library	Time
Moment	1689.744ms
Native	636.741ms
DateFns	714.148ms
DayJs	2037.603ms
Luxon	2897.571ms

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Date of Month

Gets or sets the day of the month.

// Moment.js
moment().date();
// => 9
moment().date(4);
// => "2018-09-04T09:12:49.695Z"

// Native
new Date().getDate();
// => 9
new Date().setDate(4);
// => "2018-09-04T09:12:49.695Z"

// date-fns
import getDate from 'date-fns/getDate';
import setDate from 'date-fns/setDate';
getDate(new Date());
// => 9
setDate(new Date(), 4);
// => "2018-09-04T09:12:49.695Z"

// dayjs
dayjs().date();
// => 9
dayjs().set('date', 4);
// => "2018-09-04T09:12:49.695Z"

// luxon
DateTime.utc().day;
// => 9
DateTime.utc()
  .set({ day: 4 })
  .toString();
// => "2018-09-04T09:12:49.695Z"

Performance tests

Library	Time
Moment	1381.669ms
Native	397.415ms
DateFns	588.004ms
DayJs	1218.025ms
Luxon	2705.606ms

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Day of Week

Gets or sets the day of the week.

// Moment.js
moment().day();
// => 0 (Sunday)
moment().day(-14);
// => "2018-08-26T09:12:49.695Z"

// Native
new Date().getDay();
// => 0 (Sunday)
new Date().setDate(new Date().getDate() - 14);
// => "2018-08-26T09:12:49.695Z"

// date-fns
import getDay from 'date-fns/getDay';
import setDay from 'date-fns/setDay';
getDay(new Date());
// => 0 (Sunday)
setDay(new Date(), -14);
// => "2018-08-26T09:12:49.695Z"

// dayjs
dayjs().day();
// => 0 (Sunday)
dayjs().set('day', -14);
// => "2018-08-26T09:12:49.695Z"

// Luxon
DateTime.local().weekday;
// => 7 (Sunday)
DateTime.local()
  .minus({ day: 14 })
  .toJSDate();
// => "2018-08-26T09:12:49.695Z"

Library	Time
Moment	1919.404ms
Native	543.466ms
DateFns	841.436ms
DayJs	1229.475ms
Luxon	3936.282ms

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Day of Year

Gets or sets the day of the year.

// Moment.js
moment().dayOfYear();
// => 252
moment().dayOfYear(256);
// => "2018-09-13T09:12:49.695Z"

// Native
Math.floor(
  (new Date() - new Date(new Date().getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24
);
// => 252

// date-fns
import getDayOfYear from 'date-fns/getDayOfYear';
import setDayOfYear from 'date-fns/setDayOfYear';
getDayOfYear(new Date());
// => 252
setDayOfYear(new Date(), 256);
// => "2018-09-13T09:12:49.695Z"

// dayjs ⚠️ requires dayOfYear plugin
import dayOfYear from 'dayjs/plugin/dayOfYear';
dayjs.extend(dayOfYear);
dayjs().dayOfYear();
// => 252
dayjs().dayOfYear(256);
// => "2018-09-13T09:12:49.695Z"

// Luxon
DateTime.local().ordinal;
// => 252
DateTime.local()
  .set({ ordinal: 256 })
  .toString();
// => "2018-09-13T09:12:49.695Z"

Library	Time
Moment	5511.172ms
Native	530.592ms
DateFns	2079.043ms
DayJs	-
Luxon	3540.810ms

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Week of Year

Gets or sets the week of the year.

// Moment.js
moment().week();
// => 37
moment().week(24);
// => "2018-06-10T09:12:49.695Z"

// date-fns
import getWeek from 'date-fns/getWeek';
import setWeek from 'date-fns/setWeek';
getWeek(new Date());
// => 37
setWeek(new Date(), 24);
// => "2018-06-10T09:12:49.695Z"

// native getWeek
const day = new Date();
const MILLISECONDS_IN_WEEK = 604800000;
const firstDayOfWeek = 1; // monday as the first day (0 = sunday)
const startOfYear = new Date(day.getFullYear(), 0, 1);
startOfYear.setDate(
  startOfYear.getDate() + (firstDayOfWeek - (startOfYear.getDay() % 7))
);
const dayWeek = Math.round((day - startOfYear) / MILLISECONDS_IN_WEEK) + 1;
// => 37

// native setWeek
const day = new Date();
const week = 24;
const MILLISECONDS_IN_WEEK = 604800000;
const firstDayOfWeek = 1; // monday as the first day (0 = sunday)
const startOfYear = new Date(day.getFullYear(), 0, 1);
startOfYear.setDate(
  startOfYear.getDate() + (firstDayOfWeek - (startOfYear.getDay() % 7))
);
const dayWeek = Math.round((day - startOfYear) / MILLISECONDS_IN_WEEK) + 1;
day.setDate(day.getDate() - (dayWeek - week) * 7);
day.toISOString();
// => "2018-06-10T09:12:49.794Z

// dayjs ⚠️ requires weekOfYear plugin
import weekOfYear from 'dayjs/plugin/weekOfYear';
dayjs.extend(weekOfYear);
dayjs().week();
// => 37
dayjs().week(24);
// => "2018-06-10T09:12:49.695Z"

// Luxon
DateTime.local().weekNumber;
// => 37
DateTime.local()
  .set({ weekNumber: 23 })
  .toString();
// => "2018-06-10T09:12:49.794Z

Library	Time
Moment	7147.201ms
Native	1371.631ms
DateFns	5834.815ms
DayJs	-
Luxon	4514.771ms

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Days in Month

Get the number of days in the current month.

// Moment.js
moment('2012-02', 'YYYY-MM').daysInMonth();
// => 29

// Native
new Date(2012, 02, 0).getDate();
// => 29

// date-fns
import getDaysInMonth from 'date-fns/getDaysInMonth';
getDaysInMonth(new Date(2012, 1));
// => 29

// dayjs
dayjs('2012-02').daysInMonth();
// => 29

// Luxon
DateTime.local(2012, 2).daysInMonth;
// => 29

Library	Time
Moment	4415.065ms
Native	186.196ms
DateFns	634.084ms
DayJs	1922.774ms
Luxon	1403.032ms

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Weeks in Year

Gets the number of weeks in the current year, according to ISO weeks.

// Moment.js
moment().isoWeeksInYear();
// => 52

// date-fns
import getISOWeeksInYear from 'date-fns/getISOWeeksInYear';
getISOWeeksInYear(new Date());
// => 52

// dayjs ⚠️ requires isoWeeksInYear plugin
import isoWeeksInYear from 'dayjs/plugin/isoWeeksInYear';
dayjs.extend(isoWeeksInYear);
dayjs().isoWeeksInYear();
// => 52

// Moment.js
DateTime.local().weeksInWeekYear;
// => 52

Library	Time
Moment	1065.247ms
Native	-
DateFns	4954.042ms
DayJs	-
Luxon	1134.483ms

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Maximum of the given dates

Returns the maximum (most distant future) of the given date.

const array = [
  new Date(2017, 4, 13),
  new Date(2018, 2, 12),
  new Date(2016, 0, 10),
  new Date(2016, 0, 9),
];
// Moment.js
moment.max(array.map(a => moment(a)));
// => "2018-03-11T13:00:00.000Z"

// Native
new Date(Math.max.apply(null, array)).toISOString();
// => "2018-03-11T13:00:00.000Z"

// date-fns
import max from 'date-fns/max';
max(array);
// => "2018-03-11T13:00:00.000Z"

// dayjs ⚠️ requires minMax plugin
import minMax from 'dayjs/plugin/minMax';
dayjs.extend(minMax);
dayjs.max(array.map(a => dayjs(a)));
// => "2018-03-11T13:00:00.000Z"

// Luxon
DateTime.max(...array.map(a => DateTime.fromJSDate(a))).toJSDate();
// => "2018-03-11T13:00:00.000Z"

Library	Time
Moment	1780.075ms
Native	828.332ms
DateFns	980.938ms
DayJs	-
Luxon	2694.702ms

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Minimum of the given dates

Returns the minimum (most distant future) of the given date.

const array = [
  new Date(2017, 4, 13),
  new Date(2018, 2, 12),
  new Date(2016, 0, 10),
  new Date(2016, 0, 9),
];
// Moment.js
moment.min(array.map(a => moment(a)));
// => "2016-01-08T13:00:00.000Z"

// Native
new Date(Math.min.apply(null, array)).toISOString();
// => "2016-01-08T13:00:00.000Z"

// date-fns
import min from 'date-fns/min';
min(array);
// => "2016-01-08T13:00:00.000Z"

// dayjs ⚠️ requires minMax plugin
import minMax from 'dayjs/plugin/minMax';
dayjs.extend(minMax);
dayjs.min(array.map(a => dayjs(a)));
// => "2016-01-08T13:00:00.000Z"

// Luxon
DateTime.min(...array.map(a => DateTime.fromJSDate(a))).toJSDate();
// => "2016-01-08T13:00:00.000Z"

Library	Time
Moment	1744.459ms
Native	819.646ms
DateFns	841.249ms
DayJs	-
Luxon	2720.462ms

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Manipulate

Add

Add the specified number of days to the given date.

// Moment.js
moment().add(7, 'days');
// => "2018-09-16T09:12:49.695Z"

// Native
const now = new Date();
now.setDate(now.getDate() + 7);
// => "Sun Sep 16 2018 09:12:49"

// date-fns
import addDays from 'date-fns/addDays';
addDays(new Date(), 7);
// => "2018-09-16T09:12:49.695Z"

// dayjs
dayjs().add(7, 'day');
// => "2018-09-16T09:12:49.695Z"

// Luxon
DateTime.local()
  .plus({ day: 7 })
  .toJSDate();
// => "2018-09-16T09:12:49.695Z"

Library	Time
Moment	1309.485ms
Native	259.932ms
DateFns	385.394ms
DayJs	1911.881ms
Luxon	3919.797ms

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Subtract

Subtract the specified number of days from the given date.

// Moment.js
moment().subtract(7, 'days');
// => "2018-09-02T09:12:49.695Z"

// Native
new Date(new Date().getTime() - 1000 * 60 * 60 * 24 * 7);
// => Sun Sep 09 2018 09:12:49

// date-fns
import subDays from 'date-fns/subDays';
subDays(new Date(), 7);
// => "2018-09-02T09:12:49.695Z"

// dayjs
dayjs().subtract(7, 'day');
// => "2018-09-02T09:12:49.695Z"

// Luxon
DateTime.local()
  .minus({ day: 7 })
  .toJSDate();
// => "2018-09-02T09:12:49.695Z"

Library	Time
Moment	1278.384ms
Native	215.255ms
DateFns	379.057ms
DayJs	1772.593ms
Luxon	4028.866ms

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Start of Time

Return the start of a unit of time for the given date.

// Moment.js
moment().startOf('month');
// => "2018-08-31T14:00:00.000Z"

// date-fns
import startOfMonth from 'date-fns/startOfMonth';
startOfMonth(new Date());
// => "2018-08-31T14:00:00.000Z"

// dayjs
dayjs().startOf('month');
// => "2018-08-31T14:00:00.000Z"

// Luxon
DateTime.local().startOf('month');
// => "2018-09-02T09:12:49.695Z"

Library	Time
Moment	1078.948ms
Native	-
DateFns	398.107ms
DayJs	765.358ms
Luxon	2306.765ms

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End of Time

Return the end of a unit of time for the given date.

// Moment.js
moment().endOf('day');
// => "2018-09-09T13:59:59.999Z"

// Native
const end = new Date();
end.setHours(23, 59, 59, 999);
end.toISOString();
// => "2018-09-09T16:59:59.999Z"

// date-fns
import endOfDay from 'date-fns/endOfDay';
endOfDay(new Date());
// => "2018-09-09T13:59:59.999Z"

// dayjs
dayjs().endOf('day');
// => "2018-09-09T13:59:59.999Z"

// Luxon
DateTime.local().endOf('day');
// => "2018-09-02T09:12:49.695Z"

Library	Time
Moment	1241.304ms
Native	225.519ms
DateFns	319.773ms
DayJs	914.425ms
Luxon	9920.529ms

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Display

Format

Return the formatted date string in the given format.

// Moment.js
moment().format('dddd, MMMM Do YYYY, h:mm:ss A');
// => "Sunday, September 9th 2018, 7:12:49 PM"
moment().format('ddd, hA');
// => "Sun, 7PM"

// date-fns
import format from 'date-fns/format';
format(new Date(), 'eeee, MMMM do YYYY, h:mm:ss aa');
// => "Sunday, September 9th 2018, 7:12:49 PM"
format(new Date(), 'eee, ha');
// => "Sun, 7PM"

// dayjs
dayjs().format('dddd, MMMM D YYYY, h:mm:ss A');
// => "Sunday, September 9 2018, 7:12:49 PM"
dayjs().format('ddd, hA');
// => "Sun, 7PM"
// dayjs ⚠️ requires advancedFormat plugin to support more format tokens
import advancedFormat from 'dayjs/plugin/customParseFormat';
dayjs.extend(advancedFormat);
dayjs().format('dddd, MMMM Do YYYY, h:mm:ss A');
// => "Sunday, September 9th 2018, 7:12:49 PM"

// Luxon
DateTime.fromMillis(time).toFormat('EEEE, MMMM dd yyyy, h:mm:ss a');
// => "Sunday, September 9 2018, 7:12:49 PM" ⚠️  not support 9th
DateTime.fromMillis(time).toFormat('EEE, ha');
// => "Sun, 7PM"

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Time from now

Return time from now.

// Moment.js
moment(1536484369695).fromNow();
// => "4 days ago"

// date-fns
import formatDistance from 'date-fns/formatDistance';
formatDistance(new Date(1536484369695), new Date(), { addSuffix: true });
// => "4 days ago"

// dayjs ⚠️ requires relativeTime plugin
import relativeTime from 'dayjs/plugin/relativeTime';
dayjs.extend(relativeTime);

dayjs(1536484369695).fromNow();
// => "5 days ago" ⚠️  the rounding method of this plugin is different from moment.js and date-fns, use with care.

// luxon ❌ does not support relative time

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Time from x

Return time from x.

// Moment.js
moment([2007, 0, 27]).to(moment([2007, 0, 29]));
// => "in 2 days"

// date-fns
import formatDistance from 'date-fns/formatDistance';
formatDistance(new Date(2007, 0, 27), new Date(2007, 0, 29));
// => "2 days"

// dayjs ⚠️ requires relativeTime plugin
import relativeTime from 'dayjs/plugin/relativeTime';
dayjs.extend(relativeTime);
dayjs('2007-01-27').to(dayjs('2007-01-29'));
// => "in 2 days"

// luxon ❌ does not support relative time

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Difference

Get the unit of time between the given dates.

// Moment.js
moment([2007, 0, 27]).diff(moment([2007, 0, 29]));
// => -172800000
moment([2007, 0, 27]).diff(moment([2007, 0, 29]), 'days');
// => -2

// Native
new Date(2007, 0, 27) - new Date(2007, 0, 29);
// => -172800000
Math.ceil(
  (new Date(2007, 0, 27) - new Date(2007, 0, 29)) / 1000 / 60 / 60 / 24
);
// => -2

// date-fns
import differenceInMilliseconds from 'date-fns/differenceInMilliseconds';
differenceInMilliseconds(new Date(2007, 0, 27), new Date(2007, 0, 29));
// => -172800000
import differenceInDays from 'date-fns/differenceInDays';
differenceInDays(new Date(2007, 0, 27), new Date(2007, 0, 29));
// => -2

// dayjs
dayjs('2007-01-27').diff(dayjs('2007-01-29'), 'milliseconds');
// => -172800000
dayjs('2007-01-27').diff(dayjs('2007-01-29'), 'days');
// => -2

// luxon
DateTime.local(2007, 1, 27).diff(DateTime.local(2007, 1, 29)).milliseconds;
// => -172800000
DateTime.local(2007, 1, 27).diff(DateTime.local(2007, 1, 29), 'days').days;
// => -2

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Query

Is Before

Check if a date is before another date.

// Moment.js
moment('2010-10-20').isBefore('2010-10-21');
// => true

// Native
new Date(2010, 10, 20) < new Date(2010, 10, 21);
// => true

// date-fns
import isBefore from 'date-fns/isBefore';
isBefore(new Date(2010, 9, 20), new Date(2010, 9, 21));
// => true

// dayjs
dayjs('2010-10-20').isBefore('2010-10-21');
// => true

// luxon
DateTime.fromISO('2010-10-20') < DateTime.fromISO('2010-10-21');
// => true

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Is Same

Check if a date is the same as another date.

// Moment.js
moment('2010-10-20').isSame('2010-10-21');
// => false
moment('2010-10-20').isSame('2010-10-20');
// => true
moment('2010-10-20').isSame('2010-10-21', 'month');
// => true

// Native
new Date(2010, 9, 20).valueOf() === new Date(2010, 9, 21).valueOf();
// => false
new Date(2010, 9, 20).valueOf() === new Date(2010, 9, 20).valueOf();
// => true
new Date(2010, 9, 20).getTime() === new Date(2010, 9, 20).getTime();
// => true
new Date(2010, 9, 20).valueOf() === new Date(2010, 9, 20).getTime();
// => true
new Date(2010, 9, 20).toDateString().substring(4, 7) ===
  new Date(2010, 9, 21).toDateString().substring(4, 7);
// => true

// date-fns
import isSameDay from 'date-fns/isSameDay';
import isSameMonth from 'date-fns/isSameMonth';
isSameDay(new Date(2010, 9, 20), new Date(2010, 9, 21));
// => false
isSameDay(new Date(2010, 9, 20), new Date(2010, 9, 20));
// => true
isSameMonth(new Date(2010, 9, 20), new Date(2010, 9, 21));
// => true

// dayjs
dayjs('2010-10-20').isSame('2010-10-21');
// => false
dayjs('2010-10-20').isSame('2010-10-20');
// => true
dayjs('2010-10-20').isSame('2010-10-21', 'month');
// => true

// luxon
(+DateTime.fromISO('2010-10-20') ===
  +DateTime.fromISO('2010-10-21') +
    // => false
    DateTime.fromISO('2010-10-20')) ===
  +DateTime.fromISO('2010-10-20');
// => true
DateTime.fromISO('2010-10-20').hasSame(DateTime.fromISO('2010-10-21'), 'month');
// => true

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Is After

Check if a date is after another date.

// Moment.js
moment('2010-10-20').isAfter('2010-10-19');
// => true

// Native
new Date(2010, 9, 20) > new Date(2010, 9, 19);
// => true

// date-fns
import isAfter from 'date-fns/isAfter';
isAfter(new Date(2010, 9, 20), new Date(2010, 9, 19));
// => true

// dayjs
dayjs('2010-10-20').isAfter('2010-10-19');
// => true

// luxon
DateTime.fromISO('2010-10-20') > DateTime.fromISO('2010-10-19');
// => true

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Is Between

Check if a date is between two other dates.

// Moment.js
moment('2010-10-20').isBetween('2010-10-19', '2010-10-25');
// => true

// date-fns
import isWithinInterval from 'date-fns/isWithinInterval';
isWithinInterval(new Date(2010, 9, 20), {
  start: new Date(2010, 9, 19),
  end: new Date(2010, 9, 25),
});
// => true

// dayjs ⚠️ requires isBetween plugin
import isBetween from 'dayjs/plugin/isBetween';
dayjs.extend(isBetween);
dayjs('2010-10-20').isBetween('2010-10-19', '2010-10-25');
// => true

// luxon
Interval.fromDateTimes(
  DateTime.fromISO('2010-10-19'),
  DateTime.fromISO('2010-10-25')
).contains(DateTime.fromISO('2010-10-20'));
// => true

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Is Leap Year

Check if a year is a leap year.

// Moment.js
moment([2000]).isLeapYear();
// => true

// Native
new Date(2000, 1, 29).getDate() === 29;
// => true

// date-fns
import isLeapYear from 'date-fns/isLeapYear';
isLeapYear(new Date(2000, 0, 1));
// => true

// dayjs ⚠️ requires isLeapYear plugin
import isLeapYear from 'dayjs/plugin/isLeapYear';
dayjs.extend(isLeapYear);
dayjs('2000-01-01').isLeapYear();
// => true

// luxon
expect(DateTime.local(2000).isInLeapYear).toBeTruthy();
// => true

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Is a Date

Check if a variable is a native js Date object.

// Moment.js
moment.isDate(new Date());
// => true

// Native
new Date() instanceof Date;
// => true

// date-fns
import isDate from 'date-fns/isDate';
isDate(new Date());
// => true

// dayjs
dayjs(new Date()).isValid();

// luxon
DateTime.local().isValid;
// => true

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License

MIT