Edit

Creating

To create a duration, call dayjs.duration() with the length of time in milliseconds.

This requires the Duration plugin to work

dayjs.extend(duration)

dayjs.duration(100); // 100 milliseconds

If you want to create a duration with a unit of measurement other than milliseconds, you can pass the unit of measurement as well.

dayjs.duration(2, 'days');

List of all available units

Unit	Shorthand
days	d
weeks	w
months	M
years	y
hours	h
minutes	m
seconds	s
milliseconds	ms

You can also pass an object of values if you need multiple different units of measurement.

dayjs.duration({
  seconds: 2,
  minutes: 2,
  hours: 2,
  days: 2,
  weeks: 2,
  months: 2,
  years: 2
});

Day.js also supports parsing ISO 8601 durations.

dayjs.duration('P1Y2M3DT4H5M6S');
dayjs.duration('P1M');