The dayjs npm package is a minimalist JavaScript library that parses, validates, manipulates, and displays dates and times for modern browsers with a largely Moment.js-compatible API. It is lightweight and offers various functionalities to handle dates and times effectively.
Parsing
Parse a date string into a dayjs object.
dayjs('2023-04-01')Validation
Check if a date is valid.
dayjs('2023-04-01').isValid()Manipulation
Manipulate the date by adding time to it.
dayjs().add(1, 'year')Display
Display the date in a specified format.
dayjs().format('YYYY-MM-DD')Query
Query the date to compare with another date.
dayjs().isBefore(dayjs('2023-12-31'))Localization
Localize the date to a different language.
dayjs().locale('es').format('dddd, MMMM D YYYY')Timezone
Handle timezone conversions.
dayjs().tz('America/New_York').format()Moment.js is a legacy date-time library similar to dayjs with a wide range of functionalities but is larger in size and no longer recommended for new projects.
Date-fns is a modern date utility library that provides the most comprehensive, yet simple and consistent toolset for manipulating JavaScript dates in a browser & Node.js.
Luxon is a powerful, modern, and friendly wrapper for JavaScript dates and times. It offers a fluent API and aims to be a successor to Moment.js.
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Fast 2kB alternative to Moment.js with the same modern API
Day.js is a minimalist JavaScript library for modern browsers with a largely Moment.js-compatible API. If you use Moment.js, you already know how to use Day.js.
dayjs().startOf('month').add(1, 'day').set('year', 2018).format('YYYY-MM-DD HH:mm:ss');
You have multiple ways of getting Day.js:
npm install dayjs --save
var dayjs = require('dayjs');
dayjs().format();
<!-- Latest compiled and minified JavaScript -->
<script src="https://unpkg.com/dayjs"></script>
<script>
dayjs().format();
</script>
Just download the latest version of Day.js at https://unpkg.com/dayjs/dist/
Instead of modifying the native Date.prototype, Day.js creates a wrapper for the Date object, called Dayjs object.
Dayjs object is immutable, that is to say, all API operation will return a new Dayjs object.
API will always return a new Dayjs object if not specified.
Simply call dayjs() with one of the supported input types.
To get the current date and time, just call dayjs() with no parameters.
dayjs();
Creating from a string matches ISO 8601 format.
dayjs(String);
dayjs('1995-12-25');
Passing an integer value representing the number of milliseconds since the Unix Epoch (Jan 1 1970 12AM UTC).
dayjs(Number);
dayjs(1318781876406);
Passing a pre-existing native Javascript Date object.
dayjs(Date);
dayjs(new Date(2018, 8, 18));
All Dayjs are immutable. If you want a copy of the object, just call .clone().
Calling dayjs() on a Dayjs object will also clone it.
dayjs(Dayjs);
dayjs().clone();
Check whether the Dayjs object considers the date invalid.
dayjs().isValid();
Get and set date.
Get year.
dayjs().year();
Get month.
dayjs().month();
Get day of the month.
dayjs().date();
Get day of the week.
dayjs().day();
Get hour.
dayjs().hour();
Get minute.
dayjs().minute();
Get second.
dayjs().second();
Get millisecond.
dayjs().millisecond();
Date setter. Units are case insensitive
dayjs().set((unit: String), (value: Int));
dayjs().set('month', 3); // April
dayjs().set('second', 30);
Once you have a Dayjs object, you may want to manipulate it in some way like this:
dayjs()
.startOf('month')
.add(1, 'day')
.subtract(1, 'year');
Returns a new Dayjs object by adding time.
dayjs().add((value: Number), (unit: String));
dayjs().add(7, 'day');
Returns a new Dayjs object by subtracting time. exactly the same as dayjs#add.
dayjs().subtract((value: Number), (unit: String));
dayjs().subtract(7, 'year');
Returns a new Dayjs object by by setting it to the start of a unit of time.
dayjs().startOf((unit: String));
dayjs().startOf('year');
Returns a new Dayjs object by by setting it to the end of a unit of time.
dayjs().endOf((unit: String));
dayjs().endOf('month');
Once parsing and manipulation are done, you need some way to display the Dayjs object.
Takes a string of tokens and replaces them with their corresponding date values.
dayjs().format(String);
dayjs().format(); // "2014-09-08T08:02:17-05:00" (ISO 8601, no fractional seconds)
dayjs().format('{YYYY} MM-DDTHH:mm:ssZ[Z]'); // "{2014} 09-08T08:02:17-05:00Z"
List of all available formats:
| Format | Output | Description |
|---|---|---|
YY | 18 | Two digit year |
YYYY | 2018 | Four digit year |
M | 1-12 | The month, beginning at 1 |
MM | 01-12 | The month, 2-digits |
MMM | Jan-Dec | The abbreviated month name |
MMMM | January-December | The full month name |
D | 1-31 | The day of the month |
DD | 01-31 | The day of the month, 2-digits |
d | 0-6 | The day of the week, with Sunday as 0 |
dddd | Sunday-Saturday | The name of the day of the week |
H | 0-23 | The hour |
HH | 00-23 | The hour, 2-digits |
h | 1-12 | The hour, 12-hour clock |
hh | 01-12 | The hour, 12-hour clock, 2-digits |
m | 0-59 | The minute |
mm | 00-59 | The minute, 2-digits |
s | 0-59 | The second |
ss | 00-59 | The second, 2-digits |
SSS | 000-999 | The millisecond, 3-digits |
Z | +5:00 | The offset from UTC |
ZZ | +0500 | The offset from UTC, 2-digits |
A | AM PM | |
a | am pm |
Get the difference of two Dayjs object in milliseconds or other unit.
dayjs().diff(Dayjs, unit);
dayjs().diff(dayjs(), 'years'); // 0
Outputs the number of milliseconds since the Unix Epoch
dayjs().valueOf();
Outputs a Unix timestamp (the number of seconds since the Unix Epoch).
dayjs().unix();
Get the number of days in the current month.
dayjs().daysInMonth();
Date objectGet copy of the native Date object from Dayjs object.
dayjs().toDate();
Returns an array that mirrors the parameters from new Date().
dayjs().toArray(); //[2018, 8, 18, 00, 00, 00, 000];
Serializing an Dayjs to JSON, will return an ISO8601 string.
dayjs().toJSON(); //"2018-08-08T00:00:00.000Z"
Formats a string to the ISO8601 standard.
dayjs().toISOString();
Returns an object with year, month ... millisecond.
dayjs().toObject(); // { years:2018, months:8, date:18, hours:0, minutes:0, seconds:0, milliseconds:0}
dayjs().toString();
Check if a Dayjs object is before another Dayjs object.
dayjs().isBefore(Dayjs);
dayjs().isBefore(dayjs()); // false
Check if a Dayjs object is same as another Dayjs object.
dayjs().isSame(Dayjs);
dayjs().isSame(dayjs()); // true
Check if a Dayjs object is after another Dayjs object.
dayjs().isAfter(Dayjs);
dayjs().isAfter(dayjs()); // false
Check if a year is a leap year.
dayjs().isLeapYear();
dayjs('2000-01-01').isLeapYear(); // true
FAQs
2KB immutable date time library alternative to Moment.js with the same modern API
The npm package dayjs receives a total of 17,336,279 weekly downloads. As such, dayjs popularity was classified as popular.
We found that dayjs demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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