Resolver composition only works when a function already exists

[theguacamoleking]

Hi there!

I was following your guide on Authentication and use of resolver composition to solve this. I encountered an issue whereby the method for authenticating only works for guarding fields that have a resolver.

For example, consider this schema

type Query {
  repo(id: ID!): Repo!
}

type Repo {
  id: ID!
  title: String!
  viewsThisWeek: Int! @auth(role: "ADMIN")
}

If there isn't a resolver for Repo.viewsThisWeek, any attempt to compose an authentication resolver will fail. Here's what I'm seeing at runtime

const resolvers = { Query: { repo: /* Some resolver */ } };
const authResolvers = { "Repo.viewsThisWeek": /* Some resovler */ }
const composedResolvers = composeResolver(resolvers, authResolvers);

console.log(composedResolvers)
// { Query: { repo: [Function] } }

My expectation was that this would be logged to the console

{ 
  Query: { repo: [Function] },
  Repo: { viewsThisWeek: [Function] }
}

In the case of authentication, using an @auth decorator would only work if an exhaustive resolver implementation is provided as the first argument to composeResolver with defaults for every field.