Date.diffMonths

Returns the difference between the two Dates in months.

To get the difference in years, subtract the year property of two Dates. To get the difference in days or weeks, subtract the Dates themselves and use the

Duration that results. Because converting between

months and smaller units requires a specific date (which

Durations don't have), getting the difference in

months requires some math using both the year and month properties, so this is a convenience function for getting the difference in months.

Note that the number of days in the months or how far into the month either Date is is irrelevant. It is the difference in the month property combined with the difference in years * 12. So, for instance, December 31st and January 1st are one month apart just as December 1st and January 31st are one month apart.

Parameters

rhs	The Date to subtract from this one.