The millisecond accessor property of Temporal.ZonedDateTime instances returns an integer from 0 to 999 representing the millisecond (10-3 second) component of this time.
The set accessor of millisecond is undefined. You cannot change this property directly. Use the with() method to create a new Temporal.ZonedDateTime object with the desired new value.
For general information and more examples, see Temporal.PlainTime.prototype.millisecond.
const dt = Temporal.ZonedDateTime.from(
"2021-07-01T12:34:56.123456789-04:00[America/New_York]",
);
console.log(dt.millisecond); // 123Temporal.ZonedDateTimeTemporal.ZonedDateTime.prototype.with()Temporal.ZonedDateTime.prototype.add()Temporal.ZonedDateTime.prototype.subtract()Temporal.ZonedDateTime.prototype.secondTemporal.ZonedDateTime.prototype.microsecondTemporal.ZonedDateTime.prototype.nanosecondTemporal.PlainTime.prototype.millisecond