merging date and hours in swift - swift

Question

in a mock json file, I receive separated date, start hour, end hour, so I need to merge date and a start date, then doing the same with end date. Before, I had a date like this:
23/03/2022
and code worked, now I have this, which is causing old code to crash:
"2021-06-25T07:50:56.970Z”
the portion of the object from with I get date and the hours I need
"date": "2021-06-25T07:50:56.970Z",
"time": {
"from": "17:00",
"to": "18:00"
}
code in which such date was manipulated:
public class ShortDateTimeFormatter: DateFormatter {
override public init() {
super.init()
self.dateFormat = "dd/MM/yyyy HH:mm"
}
required public init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
used here as let
private let shortTimeFormatter = ShortDateTimeFormatter()
called here
if let startTime = hours.from,
let startDate = date.concats(startTime),
let start = self.shortTimeFormatter.date(from: startDate) {
event.startDate = start
event.addAlarm(EKAlarm(absoluteDate: start.dayBefore))
event.addAlarm(EKAlarm(absoluteDate: start.halfHourBefore))
event.endDate = start.hourAfter
}
if let endTime = hours.to,
let endDate = date.concats(endTime),
let end = self.shortTimeFormatter.date(from: endDate) {
event.endDate = end
}
eventually, used here
guard let url = URL(string: "calshow:\(event.startDate.timeIntervalSinceReferenceDate)") else { return }
how can I put together a date I can use now? in other way, I think I need to get day/month/year from “2021-06-25T07:50:56.970Z” put tighter a format like the "old date" and go on. or maybe a different way to handle it is needed.

Answer 1

Here's what you can do.
import Foundation
let input = "2021-06-25T07:50:56.970Z"
let iso8601 = ISO8601DateFormatter()
iso8601.formatOptions = [.withFullDate, .withFullTime, .withFractionalSeconds]
if let date = iso8601.date(from: input) {
var calendar = Calendar.current
calendar.timeZone = TimeZone(secondsFromGMT: 0)! // same as your input time zone (and force cast tested only for UTC)
let dateComps = calendar.dateComponents([.day, .month, .year], from: date)
let start = "17:00"
let startDate = dateByAppending(time: start, to: dateComps, using: calendar)
let end = "18:00"
let endDate = dateByAppending(time: end, to: dateComps, using: calendar)
}
func dateByAppending(time: String, to dateComponents: DateComponents, using calendar: Calendar) -> Date? {
var dateComps = dateComponents
let timeComps = time.components(separatedBy: ":")
if timeComps.count == 2 {
dateComps.hour = Int(timeComps[0])
dateComps.minute = Int(timeComps[1])
}
return calendar.date(from: dateComps)
}