example.js

let BlogAuthor = new GraphQLObjectType({
  name: 'Author',
  fields: () => ({
    id: { type: GraphQLString },
    name: { type: GraphQLString }
  })
})

let BlogArticle = new GraphQLObjectType({
  name: 'Article',
  fields: {
    id: { type: new GraphQLNonNull(GraphQLString) },
    isPublished: { type: GraphQLBoolean },
    author: { type: BlogAuthor },
    title: { type: GraphQLString },
    body: { type: GraphQLString },
    keywords: { type: new GraphQLList(GraphQLString) }
  }
})

let RootQuery = new GraphQLObjectType({
  name: 'Query',
  fields: {
    article: {
      type: BlogArticle,
      args: { id: { type: GraphQLID } },
      // fetches an article from the database, including the author
      resolve: (_, {id}) => article(id)
    }
  }
})

let schema = new GraphQLSchema({
  query: RootQuery
});