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Temporal.PlainYearMonth.prototype.equals()

Limited availability

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

The equals() method of Temporal.PlainYearMonth instances returns true if this year-month is equivalent in value to another year-month (in a form convertible by Temporal.PlainYearMonth.from()), and false otherwise. They are compared both by their underlying ISO date values and their calendars, so two year-months from different calendars may be considered equal by Temporal.PlainYearMonth.compare() but not by equals().

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

Syntax

equals(other)

Parameters

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

Return value

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

Examples

Using equals()

const ym1 = Temporal.PlainYearMonth.from("2021-08");
const ym2 = Temporal.PlainYearMonth.from({ year: 2021, month: 8 });
console.log(ym1.equals(ym2)); // true

const ym3 = Temporal.PlainYearMonth.from("2021-08-01[u-ca=japanese]");
console.log(ym1.equals(ym3)); // false

const ym4 = Temporal.PlainYearMonth.from("2021-09");
console.log(ym1.equals(ym4)); // false

Specifications

Specification
Temporal> # sec-temporal.plainyearmonth.prototype.equals>

Browser compatibility

	Desktop					Mobile							Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	WebView on iOS	Bun	Deno	Node.js
`equals`	144	144	139	No	No	144	139	No	No	No	144	No	?	1.40	No