Temporal.Duration.prototype.weeks

The weeks accessor property of Temporal.Duration instances returns an integer representing the number of weeks 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 weeks, the weeks absolute value's range depends on the calendar (how many weeks are in a month or year).

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

const d1 = Temporal.Duration.from({ weeks: 1, days: 1 });
const d2 = Temporal.Duration.from({ weeks: -1, days: -1 });
const d3 = Temporal.Duration.from({ weeks: 1 });
const d4 = Temporal.Duration.from({ days: 7 });

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

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