RealmCollectionChange

@frozen
public enum RealmCollectionChange<CollectionType>

A RealmCollectionChange value encapsulates information about changes to collections that are reported by Realm notifications.

The change information is available in two formats: a simple array of row indices in the collection for each type of change, and an array of index paths in a requested section suitable for passing directly to UITableView‘s batch update methods.

The arrays of indices in the .update case follow UITableView’s batching conventions, and can be passed as-is to a table view’s batch update functions after being converted to index paths. For example, for a simple one-section table view, you can do the following:

self.notificationToken = results.observe { changes in
    switch changes {
    case .initial:
        // Results are now populated and can be accessed without blocking the UI
        self.tableView.reloadData()
        break
    case .update(_, let deletions, let insertions, let modifications):
        // Query results have changed, so apply them to the TableView
        self.tableView.beginUpdates()
        self.tableView.insertRows(at: insertions.map { IndexPath(row: $0, section: 0) },
           with: .automatic)
        self.tableView.deleteRows(at: deletions.map { IndexPath(row: $0, section: 0) },
           with: .automatic)
        self.tableView.reloadRows(at: modifications.map { IndexPath(row: $0, section: 0) },
           with: .automatic)
        self.tableView.endUpdates()
        break
    case .error(let err):
        // An error occurred while opening the Realm file on the background worker thread
        fatalError("\(err)")
        break
    }
}