soln.ts

import {
  graphql,
} from 'graphql';

import {
  makeExecutableSchema, addResolveFunctionsToSchema, IResolverObject
} from 'graphql-tools';

const types = `

type Query {
  person: User
}

type User {
  id: ID
  name: String,
  dog(showCollar: Boolean): Dog
}

type Dog {
  name: String
}

`;

const resolvers = {
  Query: {
    person(obj) {
      console.log('Person Arg 1', obj);
      return {
        id: 'foo',
        name: 'bar',
      };
    }
  }
};

const schema = makeExecutableSchema({
  typeDefs: [types],
  resolvers
});

const User: IResolverObject = {
  dog(obj, args, ctx) {
    console.log('Dog Arg 1', obj);
    return {
      name: 'doggy'
    };
  }
};

addResolveFunctionsToSchema({
  schema,
  resolvers: {
    User
  }
});

const query = `{ 
  person {
    name,
    dog(showCollar: true) {
      name
    }
  }
 }`;


graphql(schema, query).then(result => {
  console.log(JSON.stringify(result, null, 2));
});


// Person Arg 1 undefined
// Dog Arg 1 { id: 'foo', name: 'bar' }
// {
//   "data": {
//     "person": {
//       "name": "bar",
//       "dog": {
//         "name": "doggy"
//       }
//     }
//   }
// }