Temporal.PlainMonthDay.prototype.equals()

The equals() method of {{jsxref("Temporal.PlainMonthDay")}} instances returns true if this month-day is equivalent in value to another month-day (in a form convertible by {{jsxref("Temporal/PlainMonthDay/from", "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 {{jsxref("Temporal/PlainMonthDay/from", "Temporal.PlainMonthDay.from()")}} method, but can be set manually using the {{jsxref("Temporal/PlainMonthDay/PlainMonthDay", "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#

equals(other)

Parameters#

• other
• : A string, an object, or a {{jsxref("Temporal.PlainMonthDay")}} instance representing the other month-day to compare. It is converted to a Temporal.PlainMonthDay object using the same algorithm as {{jsxref("Temporal/PlainMonthDay/from", "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()#

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#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("Temporal.PlainMonthDay")}}