I can't understand the error, it can't return object in resolver

What does the query definition look in the schema (for feed). What I see is that you are not returning an array (Iterable) in the first example, but is when you return straight from

ctx.db.query.themes

query{ feed{ count lists{ id } } }

I mean what is in schema.graphql

type Feed { lists: [Theme!]! count: Int! } type Query { feed: [Feed!]! }

So [Feed!]! is an array of feeds, you want it to be

type Query {
  feed: Feed
}

I want to return a custom object in resolver

That is ok, the schema needs to be changed to match the resolver

I see. Thank you very much.

no problem