This is the identical function from that tutorial and I see no error in it at a glance.
When you call this function, is it returning the alert and the “Network error”, or what?
Where are your todos still complete at? If you query the database again are they still there or are they just still in your application?
As this appears to be your first post, I am going to assume that you are new to Dgraph. So this might be a help to you.
The tutorial you are following is using Dgraph and the DQL endpoints and clients. This is not a bad thing, but sometimes it can make things more difficult than they need to be. Dgraph offers both the DQL endpoints and a GraphQL endpoint. For starters check out: New to Dgraph? DQL vs. GraphQL Your application may require functionality that is only in DQL such as being able to run without a predefined schema or using transactions. More than likely though the GraphQL endpoint will better serve a frontend application.
These different endpoints can be quite confusing to new comers to Dgraph, If you are committed to the DQL endpoint, then your OP still needs to be resolved and the aforementioned questions will help lead to a resolution. If you are not committed to DQL and want to have the full ecosystem tools of GraphQL, can I recommend you to follow this instead:
(You don’t have to use Slash, you can run Dgraph locally for testing purposes and still use the GraphQL endpoint, you just won’t have the Slash GUI for updating the schema, using lambdas, or the API Explorer. But Slash does have a free tier at 1Mb/day transfer rate that makes getting started really easy without needing to setup and manage your own Dgraph instance)