How to add additional resolvers to a v0 .meshrc.ts?

[tmc-yuval-naveh]

I have a basic TS mesh running, from a JSON Schema source.

I managed to easily add additional type defs (the classic Query/hello field)
When I added additionalResolvers the resolver is not working.
The documentation is highly focused on yaml (where it does work) but I'm trying to use the TS config

I'm getting an error when running the query ""message": "No source found named "undefined"","

const config = {
  sources: [
    {
      name: 'XYZ_API',
      handler: {
        jsonSchema: {
             ...
       }
      }
  }],
 additionalTypeDefs: /* GraphQL */ `
    extend type Query {
      hello: String
      apple: Int
    }
  `,
  additionalResolvers: [
    {
      Query: {
        hello: () => 'This is a custom resolver value'
      }
    }
  ]