Swift: The Direction of Date.distance(to:)
The official document of Date.distance(to:)
says it:
Returns the distance from this date to another date, specified as a time interval.
But it has never been clear to me positive distance means whether the left side date is earlier or later.
So this tip is dedicated to myself: Date.distance(to:)
is the opposite of minus. The distance positive when the left side date is earlier.
$ swift
1> let now = Date()
now: Date = {}
2> let oneHourLater = now.advanced(by: 3600)
oneHourLater: Date = {}
3> let distance = now.distance(to: oneHourLater)
distance: TimeInterval = 3600