Date - Date order issue

[fever324]

If we have (not sure if it will compile, just want to show that D2 is later than D1)
D1 = "1/2/2015"
D2 = "1/2/2016"

I was expecting D2 - D1 would give me 365 days. But in fact in code we have to use D1 - D2 to get the actual time interval.

Is this intended behavior?

Thank you!

[malcommac]

Hi, you can use .in() method an specify the .day as parameter.

let D1 = try! "1/2/2015".date(format: .custom("dd/MM/yyyy"))
let D2 = try! "1/2/2016".date(format: .custom("dd/MM/yyyy"))
let v = (D2 - D1).in(.day) // 365

[fever324]

I believe this will crash because in here we specifies the lhs is the start of the interval instead of the end of the interval.

Please try run the code above and let me know!

[malcommac]

I've tried it right now; do you encounter a crash?

[fever324]

Hi @malcommac I tested your code and it works fine.
But I don't understand why using Date instead of SwiftDate.DateInRegion in the following code crashes

let today = Date()
let tomorrow = Date() + 1.days
print(tomorrow - today) // This crashes here

[malcommac]

I've tried using DateInRegion instead of Date and it still works fine, in the comments what I get

let today = DateInRegion()
let tomorrow = DateInRegion() + 1.days
let diffInDays = (tomorrow - today).in(.day) // -> 1
print(tomorrow - today) // -> in seconds = 86400.0012260079

Can you post your crash?

[fever324]

The problem is that I have to use Date().
The crash message is

fatal error: Reverse intervals are not allowed: file /Users/hongfeili/Documents/GitHub/Just Did It/Carthage/Checkouts/SwiftDate/Sources/SwiftDate/DateTimeInterval.swift, line 69

I still think the Date+Math order should be reversed or consider absolute like how it is done in DateInRegion+Math

Is the order of minus between Dates intended?

[malcommac]

Ok should be fixed 👍