How do I use a diffable data source?

To use a diffable data source, you can follow these steps:

1. Create a Data Source: Initialize a diffable data source with a table view or collection view. This data source will manage the data and provide the necessary updates to the UI.

2. Define Snapshots: Use snapshots to represent the current state of your data. A snapshot is a lightweight representation of your data that you can apply to the data source to update the UI.

3. Apply Snapshots: Apply the snapshot to the data source. The diffable data source will automatically calculate the differences and update the UI accordingly.

Here is a basic example in Swift:

import UIKit

class MyViewController: UIViewController {
    var tableView: UITableView!
    var dataSource: UITableViewDiffableDataSource<Section, Item>!

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView = UITableView(frame: view.bounds)
        view.addSubview(tableView)
        
        // Initialize the data source
        dataSource = UITableViewDiffableDataSource<Section, Item>(tableView: tableView) { (tableView, indexPath, item) -> UITableViewCell? in
            let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
            cell.textLabel?.text = item.title
            return cell
        }
        
        // Create and apply a snapshot
        var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
        snapshot.appendSections([.main])
        snapshot.appendItems([Item(title: "Item 1"), Item(title: "Item 2")])
        dataSource.apply(snapshot, animatingDifferences: true)
    }
}

enum Section {
    case main
}

struct Item: Hashable {
    let title: String
}

In this example:

• Section is an enum representing the sections in the table view.
• Item is a struct representing the items in the table view.
• UITableViewDiffableDataSource is used to manage the data and provide updates to the table view.

For more detailed information and advanced usage, you can refer to the session Track model changes with SwiftData history which covers transactions and changes, including how to handle data updates efficiently.