Object view state with Unidirectional Data Flow with Swift and Realm - ios

Question

I am using Swift with Realm to build an unidirectional data flow App.
I am wondering why I can not use an object as current application state.
var people is always updated when I add new person but var oldestPerson is never updated.
This is my Store.swift file
class Person: Object {
dynamic var name: String = ""
dynamic var age: Int = 0
}
// MARK: Application/View state
extension Realm {
var people: Results<Person> {
return objects(Person).sorted("age")
}
var oldestPerson: Person? {
return objects(Person).sorted("age").first
}
}
// MARK: Actions
extension Realm {
func addPerson(name: String, age: Int) {
do {
try write {
let person = Person()
person.name = name
person.age = age
add(person)
}
} catch {
print("Add Person action failed: \(error)")
}
}
}
let store = try! Realm()
The state of oldest in my view layer never change but people change as it should.
import RealmSwift
class PersonsTableViewController: UITableViewController {
var notificationToken: NotificationToken?
var people = store.people
var oldest = store.oldestPerson
override func viewDidLoad() {
super.viewDidLoad()
updateView()
notificationToken = store.addNotificationBlock { [weak self] (_) in
self?.updateView()
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return people.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("PersonTableViewCell") as! PersonTableViewCell
cell.person = people[indexPath.row]
return cell
}
func updateView() {
print(oldest)
tableView.reloadData()
}
}

Answer 1

Change your declaration of
var oldest = store.oldestPerson
to:
var oldest: Person? { return store.oldestPerson }