Get time from timestamp string that includes timezone

Question

I receive a date

let slotDateString: String =  "2023-12-06T15:45:00+04:00"

I have two formatters:

var iso8601FormatterWithFullTimeZone: DateFormatter {
    let formatter = DateFormatter(withFormat: "yyyy-MM-dd'T'HH:mm:ssZZZZZ")
    formatter.locale = Locale(identifier: "en_US_POSIX")
    formatter.timeZone = .current

    return formatter
}

var hoursMinutesFormatter: DateFormatter {
    let formatter = DateFormatter(withFormat: "HH:mm")
    formatter.locale = Locale(identifier: "en_US_POSIX")
    formatter.timeZone = .current

    return formatter
}

When I run the following code:

let dateFormatter: DateFormatter = .iso8601FormatterWithFullTimeZone
let hoursMinutesFormatter: DateFormatter = .hoursMinutesFormatter

guard let slotDate: Date = dateFormatter.date(from: slotDateString) else {
     return
}

let slotHour: String = hoursMinutesFormatter.string(from: slotDate)

The slotDate returns me 2023-12-06 12:45:00 +0000and the slotHour returns me "12:45"

I live in timezone +01:00, but I want to get a date and an hour that take into account offset given in the original string. So slotDate should have value of something like 2023-12-06 15:45:00 +4000 or 2023-12-06 12:45:00 +0100 and slotHour should have exactly "15:45"

Answer 1

You can drop the timezone part and then get the hour:

let slotDateString = String("2023-12-06T15:45:00+01:00".dropLast(6)) // 👈 Drop timezone from the string
var iso8601FormatterWithFullTimeZone: DateFormatter {
    let formatter = DateFormatter(withFormat: "yyyy-MM-dd'T'HH:mm:ss") // 👈 No timezone in the formatter
    ,,,
}

So the slotHour would be exactly "15:45"