The inLeapYear accessor property of Temporal.PlainYearMonth instances returns a boolean indicating whether this year-month is in a leap year. A leap year is a year that has more days (due to a leap day or leap month) than a common year. It is calendar-dependent.

The set accessor of inLeapYear is undefined. You cannot change this property directly.

For general information and more examples, see Temporal.PlainDate.prototype.inLeapYear.

Examples

Using inLeapYear

const ym = Temporal.PlainYearMonth.from("2021-07");
console.log(ym.inLeapYear); // false
console.log(ym.daysInYear); // 365
console.log(ym.monthsInYear); // 12

Specifications

Browser compatibility

See also

• Temporal.PlainYearMonth
• Temporal.PlainYearMonth.prototype.with()
• Temporal.PlainYearMonth.prototype.add()
• Temporal.PlainYearMonth.prototype.subtract()
• Temporal.PlainYearMonth.prototype.year
• Temporal.PlainYearMonth.prototype.daysInYear
• Temporal.PlainYearMonth.prototype.monthsInYear
• Temporal.PlainDate.prototype.inLeapYear