date-fns

What is date-fns?

The date-fns npm package provides a comprehensive, yet simple and consistent toolset for manipulating JavaScript dates in a browser & Node.js. It offers a variety of functions to parse, validate, manipulate, and format dates.

What are date-fns's main functionalities?

Parsing Dates

Parse strings in ISO format to JavaScript Date objects.

const parseISO = require('date-fns/parseISO');
const result = parseISO('2023-04-12');

Formatting Dates

Format Date objects into strings with a given format.

const format = require('date-fns/format');
const result = format(new Date(2023, 3, 12), 'yyyy-MM-dd');

Comparing Dates

Compare two dates to determine if one comes before the other.

const isBefore = require('date-fns/isBefore');
const result = isBefore(new Date(2023, 3, 12), new Date(2023, 3, 13));

Manipulating Dates

Perform date calculations such as adding or subtracting time spans.

const addDays = require('date-fns/addDays');
const result = addDays(new Date(2023, 3, 12), 10);

Validating Dates

Check if a date is valid.

const isValid = require('date-fns/isValid');
const result = isValid(new Date('2023-04-12'));

Other packages similar to date-fns

moment

Moment.js is a legacy project, now in maintenance mode, which provides similar functionalities for parsing, validating, manipulating, and formatting dates. It's more object-oriented and mutable compared to the functional and immutable design of date-fns.

dayjs

Day.js is a lightweight date library that offers a similar API to Moment.js but with a smaller footprint. It is immutable and chainable, like date-fns, but with a different plugin system for extending functionality.

luxon

Luxon is a powerful, modern, and chainable library for working with dates and times. It offers a rich set of features for parsing, formatting, manipulating, and querying dates. It's built on the Intl API and provides time zone support out of the box, which is more comprehensive than date-fns's approach to time zones.

README

🔥️ NEW: date-fns v4.0 with first-class time zone support is out!

date-fns provides the most comprehensive, yet simple and consistent toolset for manipulating JavaScript dates in a browser & Node.js

👉 Documentation

👉 Blog

---

It's like Lodash for dates

• It has 200+ functions for all occasions.
• Modular: Pick what you need. Works with webpack, Browserify, or Rollup and also supports tree-shaking.
• Native dates: Uses existing native type. It doesn't extend core objects for safety's sake.
• Immutable & Pure: Built using pure functions and always returns a new date instance.
• TypeScript: The library is 100% TypeScript with brand-new handcrafted types.
• I18n: Dozens of locales. Include only what you need.
• and many more benefits

import { compareAsc, format } from "date-fns";

format(new Date(2014, 1, 11), "yyyy-MM-dd");
//=> '2014-02-11'

const dates = [
  new Date(1995, 6, 2),
  new Date(1987, 1, 11),
  new Date(1989, 6, 10),
];
dates.sort(compareAsc);
//=> [
//   Wed Feb 11 1987 00:00:00,
//   Mon Jul 10 1989 00:00:00,
//   Sun Jul 02 1995 00:00:00
// ]

The library is available as an npm package. To install the package run:

npm install date-fns --save

Docs

See date-fns.org for more details, API, and other docs.

License

MIT © Sasha Koss

Changelog

v4.0.0 - 2024-09-??

I have great news! First, ten years after its release, date-fns finally gets first-class time zone support.

Another great news is that there aren't many breaking changes in this release. All of them are type-related and will affect only those explicitly using internal date-fns types. Finally, it has been less than a year since the last major release, which is an improvement over the previous four years between v2 and v3. I plan on keeping the pace and minimizing breaking changes moving forward.

Read more about the release in the announcement blog post.

- Sasha @kossnocorp

Added

• Added time zones support via @date-fns/tz's TZDate class and tz helper function. See its README for the details about the API.

• All relevant functions now accept the context in option, which allows to specify the time zone to make the calculations in. If the function also returns a date, it will be in the specified time zone:

  import { addDays, startOfDay } from "date-fns";
  import { tz } from "@date-fns/tz";
  
  startOfDay(addDays(Date.now(), 5, { in: tz("Asia/Singapore") }));
  //=> "2024-09-16T00:00:00.000+08:00"
  

  In the example, addDays will get the current date and time in Singapore and add 5 days to it. startOfDay will inherit the date type and return the start of the day in Singapore.

Changed

• The function arguments, as well as Interval's start and end, now can be of different types, allowing you to mix UTCDate, TZDate, Date, and other extensions, as well as primitives (strings and numbers).

  The functions will normalize these values, make calculations, and return the result in the same type, preventing any bugs caused by the discrepancy. If passed, the type will be inferred from the context in option or the first encountered argument object type. The Interval's start and end will be considered separately, starting from start.

  In the given example, the result will be in the TZDate as the first argument is a number, and the start takes precedence over the end.

  clamp(Date.now(), {
    start: new TZDate(start, "Asia/Singapore"),
    end: new UTCDate(),
  });
  //=> TZDate
  

• BREAKING: This release contains a bunch of types changes that should not affect the library's expected usage. The changes are primarily internal and nuanced, so rather than listing them here, I recommend you running the type checker after the upgrade. If there are unfixable problems, please open an issue.

• BREAKING: The package now is ESM-first. The CommonJS is still support and It should not affect most users, but it might break in certains environments. If you encounter any issues, please report them.

Fixed

• Fixed CDN build compatibility with jQuery and other tools that expose $ by properly wrapping the code in an IIFE.