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Is Before

This indicates whether the Day.js object is before the other supplied date-time.

dayjs().isBefore(dayjs('2011-01-01')) // default milliseconds

If you want to limit the granularity to a unit other than milliseconds, pass it as the second parameter.

dayjs().isBefore('2011-01-01', 'year')

Units are case insensitive, and support plural and short forms.

List of all available units