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

githubTodo/TodoVC.swift
// 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,

// 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.

// 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)
}
}
Close

Get Started with GraphQL Now

Hasura Cloud gives you a fully managed, production ready GraphQL API as a service to help you build modern apps faster.
Ready to get started?
Start for free on Hasura Cloud or you could contact our sales team for a detailed walk-through on how Hasura may benefit your business.
Stay in the know
Sign up for full access to our community highlights, new features, and occasional baby animal gifs! Oh, and we have a strict no-spam rule. ✌️