The months accessor property of Temporal.Duration instances returns an integer representing the number of months in the duration.

Unless the duration is balanced, you cannot assume the range of this value, but you can know its sign by checking the duration's sign property. If it is balanced to a unit above months, the months absolute value's range depends on the calendar (how many months are in a year).

The set accessor of months is undefined. You cannot change this property directly. Use the with() method to create a new Temporal.Duration object with the desired new value.

Examples

Using months

const d1 = Temporal.Duration.from({ years: 1, months: 1 });
const d2 = Temporal.Duration.from({ years: -1, months: -1 });
const d3 = Temporal.Duration.from({ years: 1 });
const d4 = Temporal.Duration.from({ months: 12 });

console.log(d1.months); // 1
console.log(d2.months); // -1
console.log(d3.months); // 0
console.log(d4.months); // 12

// Balance d4
const d4Balanced = d4.round({
  largestUnit: "years",
  relativeTo: Temporal.PlainDate.from("2021-01-01"), // ISO 8601 calendar
});
console.log(d4Balanced.months); // 0
console.log(d4Balanced.years); // 1

Specifications

Browser compatibility

See also

• Temporal.Duration
• Temporal.Duration.prototype.years
• Temporal.Duration.prototype.weeks
• Temporal.Duration.prototype.days
• Temporal.Duration.prototype.hours
• Temporal.Duration.prototype.minutes
• Temporal.Duration.prototype.seconds
• Temporal.Duration.prototype.milliseconds
• Temporal.Duration.prototype.microseconds
• Temporal.Duration.prototype.nanoseconds