Mutation and update cache

Now let's do the integration part. Open Todo/TodoVC.swift and add the following code to define the delete mutation

Todo/TodoVC.swift

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    // Remove Todos from cloud
    private func removeTodosMutationCloud(indexPath: IndexPath!){
        let id = filteredTodos[indexPath.row].id
        apollo.perform(mutation: RemoveTodoMutation(id: id)) { (result, error) in
            guard let data = result?.data else { return }
            if data.deleteTodos?.affectedRows == 1 {
                let index = self.filteredTodos.firstIndex{$0.id == id}!
                self.todos.remove(at: index)
                self.filteredTodos.remove(at: index)
                // Remove from local
                self.removeTodosMutationLocal(id: id)
                DispatchQueue.main.async {
                    self.toggleCompleteAction()
                    // Delete the table view row
                    self.todoTable.deleteRows(at: [indexPath], with: .fade)
                }
            }
        }
    }

Also, the function to remove todos from the localcache,

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 // Remove Todos to local cache
    private func removeTodosMutationLocal(id: Int){
        _ = apollo.store.withinReadWriteTransaction{ transaction in
            let query = GetMyTodosQuery()
            try transaction.update(query: query) { (data: inout GetMyTodosQuery.Data) in
                let todos = data.todos
                if ( id == -1 ) {
                    data.todos = data.todos.filter({!$0.isCompleted})
                } else {
                    guard let index = todos.firstIndex(where: {$0.id == id}) else {return}
                    data.todos.remove(at: index)
                }
                
                _ = self.apollo.store.load(query: query).andThen({ (data) in
                    // Watch your data in local cache
                    // dump(data.data?.resultMap)
                    // Look for errors
                    // dump(data.errors)
                })
            }
        }
    }
}

We have a function defined to handle the swipe to remove a todo. Let's update the function.

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      // Swipe Row to Delete
    func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            // remove the item from the data model
-            self.removeTodos(indexPath: indexPath.row)
+            self.removeTodosMutationCloud(indexPath: indexPath)
        }
    }