Configuration
Theunit field selects the boundary to snap to: :day (default), :week, or :month.
Output type
The output type follows the input type: aDate becomes a Date, a NaiveDateTime or DateTime becomes the same type set to the end of the unit. Strings (ISO8601) and integers (Unix seconds) are parsed first, with strings producing whichever date type ISO8601 indicates and integers producing a DateTime (UTC).