我正在尝试从FirebaseStore获取时间戳，然后制作一个Decodable对象

Question

创建项目时，我创建了一个Project类，并在timeStamp中为其指定了一个日期。 我无法将timeStamp的项目对象的Date转换为Decodable

我试图将timeStamp返回到Double，然后将其转换为Date (timeIntervalSince1970: timestamp / 100)

我的班级：

 class Project: Decodable, Identifiable{
    var idP: String? = nil
    var memberP: [String]
    var nameP: String
    var ratioP:Int
    var startDateP:Date
    var state: Int

    init(idP:String, menberP:[String], nameP: String, ratioP: Int, timestamp:Double, state:Int) {
        self.idP = idP
        self.memberP = menberP
        self.nameP = nameP
        self.ratioP = ratioP
        self.startDateP = Date(timeIntervalSince1970: timestamp / 100)
        self.state = state
    }

//扩展日期

extension Date
{
    func calenderTimeSinceNow() -> String
    {
        let calendar = Calendar.current

        let components = calendar.dateComponents([.year, .month, .day, .hour, .minute, .second], from: self, to: Date())

        let years = components.year!
        let months = components.month!
        let days = components.day!
        let hours = components.hour!
        let minutes = components.minute!
        let seconds = components.second!

        if years > 0 {
            return years == 1 ? "1 year ago" : "\(years) years ago"
        } else if months > 0 {
            return months == 1 ? "1 month ago" : "\(months) months ago"
        } else if days >= 7 {
            let weeks = days / 7
            return weeks == 1 ? "1 week ago" : "\(weeks) weeks ago"
        } else if days > 0 {
            return days == 1 ? "1 day ago" : "\(days) days ago"
        } else if hours > 0 {
            return hours == 1 ? "1 hour ago" : "\(hours) hours ago"
        } else if minutes > 0 {
            return minutes == 1 ? "1 minute ago" : "\(minutes) minutes ago"
        } else {
            return seconds == 1 ? "1 second ago" : "\(seconds) seconds ago"
        }
    }

}

func read <T: Decodable>(from collectionReference: FIRCollectionReference, returning objectType: T.Type, completion: @escaping ([T]) -> Void)
        {
            reference(to: collectionReference).addSnapshotListener { (snapshot, _) in
            guard let snapshot = snapshot else {return}

                do {

                    var objetcs = [T]()
                    for document in snapshot.documents {
                    let object = try document.decode(as: objectType.self)
                        objetcs.append(object)
                    }
                    completion(objetcs)


                } catch {
                    print(error)
                }
        }
    }
```

the error in my console :

```
2019-05-09 23:12:07.302957+0200 GestionDeProjet[11755:366660] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Invalid type in JSON write (FIRTimestamp)'
*** First throw call stack:
```

Thanks to everyone who will read this post for your time:)