Temporal.PlainMonthDay.prototype.equals()

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The equals() method of Temporal.PlainMonthDay instances returns true if this month-day is equivalent in value to another month-day (in a form convertible by Temporal.PlainMonthDay.from()), and false otherwise. They are compared both by their underlying ISO date values and their calendars.

Note: PlainMonthDay objects keep track of a reference ISO year, which is also used in the comparison. This year is automatically set when using the Temporal.PlainMonthDay.from() method, but can be set manually using the Temporal.PlainMonthDay() constructor, causing two equivalent month-days to be considered different if they have different reference years. For this reason, you should avoid using the constructor directly and prefer the from() method.

Syntax

js
equals(other)

Parameters

other

A string, an object, or a Temporal.PlainMonthDay instance representing the other month-day to compare. It is converted to a Temporal.PlainMonthDay object using the same algorithm as Temporal.PlainMonthDay.from().

Return value

true if this month-day is equal to other both in their date value and their calendar, false otherwise.

Examples

Using equals()

js
const md1 = Temporal.PlainMonthDay.from("2021-08-01");
const md2 = Temporal.PlainMonthDay.from({ year: 2020, month: 8, day: 1 }); // Year doesn't matter
console.log(md1.equals(md2)); // true

const md3 = Temporal.PlainMonthDay.from("2021-08-01[u-ca=japanese]");
console.log(md1.equals(md3)); // false

const md4 = Temporal.PlainMonthDay.from("2021-08-02");
console.log(md1.equals(md4)); // false

Specifications

Specification
Temporal proposal
# sec-temporal.plainmonthday.prototype.equals

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
equals
Experimental

Legend

Tip: you can click/tap on a cell for more information.

No support
No support
Experimental. Expect behavior to change in the future.
See implementation notes.
User must explicitly enable this feature.

See also