Converting timestamp from Firebase and adding to array - swift

Question

I'm trying to read a timeStamp from Firebase and append it to an array.
I have made some progress:
var orderDateHistoryArray = [String:Int]()
func getOrderDates() {
let uid = Auth.auth().currentUser!.uid
let orderDateHistoryRef = Database.database().reference().child("users/\(uid)/Orders/")
orderDateHistoryRef.observeSingleEvent(of: .value, with: { (snapshot) in
// Get dates
let value = snapshot.value as? NSDictionary
if let orderDate = value?["Date"] as? [String:Int] {
self.orderDateHistoryArray += Array(orderDate.values)//This does not conform
print(orderDate)
}
self.tableView.reloadData()
// ...
}) { (error) in
print(error.localizedDescription)
}
}
The print(orderDate)statement prints:
["-LQYspEghK3KE27MlFNE": 1541421618601,
"-LQsYbhf-vl-NnRLTHhK": 1541768379422,
"-LQYDWAKlzTrlTtO1Qiz": 1541410526186,
"-LQsILjpNqKwLl9XBcQm": 1541764115618]
This is childByAutoID : timeInMilliseconds
So, I want to read out the timeInMilliseconds, convert it to a readable timestampand append it to the orderDateHistoryArray

Answer 1

Those are timestamps. Parse it as a Date object then use .toLocaleDateString to get date.
alert( new Date(1541421618601).toLocaleDateString("en-US") );

Answer 2

In order to transform your timestamp you must, first remove milliseconds on each the values returned by the dictionary.
self.orderDateHistoryArray += Array(orderDate.values).map { Date(timeIntervalSince1970: TimeInterval($0/1000)) }
In order to get it in a "human way", you need to have a DateFormatter. It's on this object where you define how it's presented.
extension Date {
func format(_ dateFormat: String = "dd/MMMM")
let formatter = DateFormatter()
formatter.timeZone = TimeZone.current
formatter.dateFormat = "MMMM dd"
return formatter.string(from: self)
}
}
and on a Date element you can just call it by date.format() or by passing a string date.format("yyyy-MM-dd'T'HH:mm:ss.SSSXXXXX")