String Date to Date

[tera]

From apple docs:

Working With Fixed Format Date Representations

...
When working with fixed format dates, such as RFC 3339, you set the dateFormat property to specify a format string. For most fixed formats, you should also set the locale property to a POSIX locale ("en_US_POSIX" ), and set the timeZone property to UTC.

let isoDate = "2022-12-14T04:30:00+05:30"

let fixedFormatter = DateFormatter()
fixedFormatter.locale = Locale(identifier: "en_US_POSIX")
fixedFormatter.timeZone = TimeZone(secondsFromGMT: 0)
fixedFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZ"

let date = fixedFormatter.date(from: isoDate)!

let displayFormatter = DateFormatter()
displayFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZ"
// uses current locale and current time zone
// overriding those, for test
displayFormatter.locale = Locale(identifier: "en_US_POSIX")
displayFormatter.timeZone = TimeZone(secondsFromGMT: (5*60+30)*60)
let dateString = displayFormatter.string(from: date)

print("date: \(date)") // 2022-12-13 23:00:00 +0000
print("dateString: \(dateString)") // 2022-12-14T04:30:00GMT+05:30

Note:

Important

In macOS 10.12 and later or iOS 10 and later, use the ISO8601DateFormatter class when working with ISO 8601 date representations.

The reason for this warning is unknown to me but I would not ignore it.

Also there are a newer FormatStyle and ParseableFormatStyle (macOS 12 and later, iOS 15 and later)