How to get UTC timestamp of a specific hour? - ios

Question

I get the current UTC timestamp using Timezone(abbreviation:"UTC") but can't get the UTC timestamp of some other timestamp.
/*Current local time (4:15 PM) ---> Current UTC (11:15 AM)
Some other time (11:15 PM) ---> UTC (6:15 PM)*/
static func getDateFormat(by date:Date, format:String) -> String {
let formatter = DateFormatter()
formatter.dateFormat = format
formatter.timeZone = TimeZone(abbreviation: "UTC")
formatter.locale = Locale.current
return formatter.string(from: date)
}
This always give the current UTC.

Answer 1

func convertToUTC(dateToConvert:String) -> String {
let formatter = DateFormatter()
formatter.dateFormat = "dd-MM-yyyy hh:mm a"
let convertedDate = formatter.date(from: dateToConvert)
formatter.timeZone = TimeZone(identifier: "UTC")
return formatter.string(from: convertedDate!)
}

Answer 2

Your question is not explained properly, though i got your question after reading it multiple times.
You want a function in which you provide a date and that function return you a new date in UTC format.
func convertDateToUTC(date: Date) -> Date {
let calendar = Calendar.current
let dateComponent = calendar.dateComponents([.timeZone], from: date)
//get difference of curent time zone from gmt
//subtract 0 as we want UTC from current time zone
let gmtDiff = 0-dateComponent.timeZone!.secondsFromGMT()
let dateStr = "11:15 PM"
let formatter = DateFormatter()
formatter.dateFormat = "h:mm a"
let date1 = formatter.date(from: dateStr)
let newDate = date1?.addingTimeInterval(TimeInterval(gmtDiff))
return newDate
}
You can format method as your convenience.
We need date components to get time zone difference of current to UTC, then we add that seconds to date and new date we get will be UTC date .