A straight-line month from today's counters.
Today's total is the daily rate times the days in the month. The elapsed fraction is reported and never divided by (that would multiply a few hours of day 1 by thirty); partialDay flags a figure resting on one incomplete day.
partialDay
clamped into 1..daysInMonth; a non-finite value reads as day 1
Optional
A straight-line month from today's counters.
Today's total is the daily rate times the days in the month. The elapsed fraction is reported and never divided by (that would multiply a few hours of day 1 by thirty);
partialDayflags a figure resting on one incomplete day.