Decoding JSON data in swift4 with dates - json

Question

Im new at this and having some trouble getting my head around how this all works.
I have this struct:
struct EventDetail:Decodable {
let EventName: String
let EventInformation: String
let EventStartDate: Date
let EventEndDate: Date
}
And this func to download the json:
func downloadJSON(completed: #escaping () -> ()) {
let url = URL(string: "http://someurl.php")
URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error == nil {
do {
self.events = try JSONDecoder().decode([EventDetail].self, from: data!)
DispatchQueue.main.async {
completed()
}
}catch {
print(error)
}
}
}.resume()
}
}
This is the JSON error I get:
JSON Error
typeMismatch(Swift.Double, Swift.DecodingError.Context(codingPath: [Foundation.(_JSONKey in _12768CA107A31EF2DCE034FD75B541C9)(stringValue: "Index 0", intValue: Optional(0)), Cosplay_Life.EventDetail.(CodingKeys in _52013DB7ECF3BE1EBFBF83BE6BA8F9E9).EventStartDate], debugDescription: "Expected to decode Double but found a string/data instead.", underlyingError: nil))
This all seems to be working if the EventStartDate and EventEndDate is a String, but I do wish to have it as a Date because I will sort data later using the date field. The value that gets downloaded is in the format "yyyy-MM-dd" eks: "2017-02-25" What am I doing wrong?

Answer 1

A date is a Double in that it is the number of ms since the epoch.
Try this:
let dateFormatter = DateFormatter()
dateFormatter.locale = Locale(identifier: "en_US_POSIX")
// Use format appropriate to your JSON String. This is for ISO-8601
// You MUST account for the milliseconds even if you don't want them
// or it won't parse properly
dateFormatter.dateFormat = "yy-MM-dd'T'HH:mm:ss.SSS"
eventDetail.EventStartDate = dateFormatter.date(from: jsonEventStartDateField)!
eventDetail.EventEndDate = dateFormatter.date(from: jsonEventEndDateField)!