The monthsInYear accessor property of Temporal.PlainDateTime instances returns a positive integer representing the number of months in the year of this date. It is calendar-dependent.
The set accessor of monthsInYear is undefined. You cannot change this property directly.
For general information and more examples, see Temporal.PlainDate.prototype.monthsInYear.
const dt = Temporal.PlainDateTime.from("2021-07-01");
console.log(dt.monthsInYear); // 12Temporal.PlainDateTimeTemporal.PlainDateTime.prototype.with()Temporal.PlainDateTime.prototype.add()Temporal.PlainDateTime.prototype.subtract()Temporal.PlainDateTime.prototype.yearTemporal.PlainDateTime.prototype.monthTemporal.PlainDateTime.prototype.monthCodeTemporal.PlainDateTime.prototype.daysInMonthTemporal.PlainDate.prototype.monthsInYear