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	Tree-shaking	Methods richness	Pattern	Locale	Timezone Support	Popularity (stars)	Sizes
Moment.js	No	High	OO	123	Good (moment-timezone)
Luxon	No	High	OO	-	Good (Intl)
date-fns	Yes	High	Functional	64	Good (date-fns-tz)
dayjs	No	High	OO	138	Good (Intl)

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.

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.

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"

// Temporal
const datePattern = /^(\d{2})-(\d{2})-(\d{4})$/;
const [, month, day, year] = datePattern.exec('12-25-1995');
new Temporal.ZonedDateTime.from({year, month, day, timeZone: Temporal.Now.timeZone()});
// => "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"

// Temporal
const datePattern = /^(\d{4})-(\d{2})-(\d{2})\s(\d{1,2}):(\d{2})$/;
const [, year, month, day, hour, minute] = datePattern.exec('2010-10-20 4:30');
new Temporal.ZonedDateTime.from({year, month, day, hour, minute, timeZone: Temporal.Now.timeZone()});
// => "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();
// =>