The subtract() method of Temporal.PlainDateTime instances returns a new Temporal.PlainDateTime object representing this date-time moved backward by a given duration (in a form convertible by Temporal.Duration.from()).
If you want to subtract two date-times and get a duration, use since() or until() instead.
subtract(duration)
subtract(duration, options)durationA string, an object, or a Temporal.Duration instance representing a duration to subtract from this date-time. It is converted to a Temporal.Duration object using the same algorithm as Temporal.Duration.from().
options OptionalAn object containing the following property:
overflow OptionalA string specifying the behavior when a date component is out of range. Possible values are:
"constrain" (default)The date component is clamped to the valid range.
"reject"A RangeError is thrown if the date component is out of range.
A new Temporal.PlainDateTime object representing the date-time specified by the original PlainDateTime, minus the duration.
RangeErrorThrown if the result is not in the representable range, which is ±(108 + 1) days, or about ±273,972.6 years, from the Unix epoch.
Subtracting a duration is equivalent to adding its negation, so all the same considerations apply.
const start = Temporal.PlainDateTime.from("2022-01-01T12:34:56");
const end = start.subtract({
years: 1,
months: 2,
weeks: 3,
days: 4,
hours: 5,
minutes: 6,
seconds: 7,
milliseconds: 8,
});
console.log(end.toString()); // 2020-10-07T07:28:48.992