如何在GraphQL中展平对象？

query {
  user {
    name
    address {
      city
      country
    }
  }
}

query {
  user {
    name
    addressCity: address {
      city
    }
    addressCountry: address {
      country
    }
  }
}

const resolvers = {
  Query: {
    user: () => {
      const user = {
        name: "John",
        address: {
          city: "New York",
          country: "USA"
        }
      };
      return flattenObject(user);
    }
  }
};

function flattenObject(obj) {
  const flattened = {};
  for (const key in obj) {
    if (typeof obj[key] === "object") {
      const nestedObj = obj[key];
      for (const nestedKey in nestedObj) {
        flattened[`${key}${nestedKey}`] = nestedObj[nestedKey];
      }
    } else {
      flattened[key] = obj[key];
    }
  }
  return flattened;
}