Convert String to Date with phones with differents date formats [duplicate] - ios

Question

This question already has an answer here:
DateFormatter doesn't return date for "HH:mm:ss"
(1 answer)
Closed 2 years ago.
I have some troubles parsing string date to Date format.
I recibe from one API the date string with this format 2020-08-27 12:39:32 (the date come in 24 hour format) and I have an extension of String to convert it to Date. So I do the convertion like this:
apiTime.toDate(format: "yyyy-MM-dd HH:mm:ss")
All works fine if the phone is configured with 24 hour. The problem came when the app runs in a AM/PM date format because the date return nil.
This is my extension to convert String to Date.
extension String {
func toDate(format: String) -> Date? {
let dateFormatter = DateFormatter()
dateFormatter.amSymbol = "AM"
dateFormatter.pmSymbol = "PM"
dateFormatter.dateFormat = format
return dateFormatter.date(from: self) //here return nil with AM/PM format
}
}

Answer 1

As suggested by #LeoDabus it's better not to create DateFormatter every time (this is very resource-consuming). You can extract it, eg. as a static property.
Here is a simple demo:
class Test {
static let dateFormatter: DateFormatter = {
let dateFormatter = DateFormatter()
dateFormatter.locale = Locale(identifier: "en_US_POSIX")
dateFormatter.timeZone = TimeZone(abbreviation: "UTC")
return dateFormatter
}()
func parseDateExample() {
let apiTime = "2020-08-27 12:39:32"
if let date = apiTime.toDate(formatter: Self.dateFormatter, format: "yyyy-MM-dd HH:mm:ss") {
print(date)
} else {
print("error")
}
}
}
You can reuse the formatter in your String extension instead of creating a new one every time you call toDate:
extension String {
func toDate(formatter: DateFormatter, format: String) -> Date? {
formatter.dateFormat = format
return formatter.date(from: self)
}
}