Approach

As mentioned before, resolver can return whatever value is defined (as long as it complies to the return type defined).

Type resolver is NOT a native mechanism provided by Graphql, rather it's a concept/pattern that can be enforced in the code base.

Field Resolvers

Field Resolvers represent specific data returned to fulfill the field value requested.

export const someField: SomeFieldType = async(parent, args, context, info) => {
  const someResult = await someService.fetchValue(parent.id);

  return {
    ...someResult
  }
}

Type Resolvers

Type Resolvers return response for node compliant to its type data shape.

• e.g. User node would have a type resolver which returns whole integrity of User fields wherever it may be used (via type User).

// calling the type resolver at query resolver layer
export const someField: SomeFieldType = async(parent, args, context, info) =>{
  return {
    ...new NodeName(parent, args)
  }
}

// implementation is uniform, common, and shared
class NodeName{
  constructor(parent, args){
    this.id = parent.id
  }

  async someDetail() {
    const fetchedDetail = someService.findSomeDetail(this.id);

    return fetchedDetail;
  }

  async complexResponse() {
    // ...

    return {
      // ...
    }
  }
}

Caveat that when using the class type resolver approach, avoid bloating it with too many functionalities attached to it.