Clearing :Date field in Realm when updating object - swift

Question

I have the following data model
#objc dynamic var uid = UUID().uuidString;
#objc dynamic var completed: Bool = false;
#objc dynamic var dateCompleted: Date?;
When I create a new object it has nil for the dateCompleted, then when the user completes the task I try to update the object with primaryKey (uid) like so
let query = realm.objects(Tasks.self).filter("uid = %#", id).first!;
if query.completed == false {
var date = Date();
} else {
var date: Date = nil
}
let wayUpdate = ["uid": id, "completed": !query.completed, "dateCompleted": date] as [String : Any]
do {
try realm.write {
realm.create(WaysData.self, value: wayUpdate, update: true)
}
} catch {
print("Error adding update to experience! \(error)");
}
I get the following error Cannot convert value of type 'String' to specified type 'Date' in the else block.
My question is - is there a way to clear the date when updating completion to false, or should I just leave dateCompleted as Date() each time the user completes/uncompletes/completes the task and just do a check on the completed: Bool value whenever I want to update the completion button's label to "Complete" or "Revive"?

Answer 1

If you simply want to update a single property of your Object subclass instance, don't call create, simply modify that single property in a write transaction.
do {
try realm.write {
query.dateCompleted = query.completed ? nil : Date()
}
} catch {
print("Error adding update to experience! \(error)")
}
You should also use the primary key to retrieve the object, don't filter the query.
let query = realm.object(ofType: Tasks.self,forPrimaryKey: id)
Unrelated to your issue, but you shouldn't use ; at the end of your lines in Swift, this is not Objective-C.