GraphlQL UnionType and InterfaceType

unionAndInterface.js

import {
  GraphQLID,
  GraphQLInt,
  GraphQLString,
  GraphQLObjectType,
  GraphQLList,
  GraphQLNonNull,
  OrderTypeEnum,
  GraphQLUnionType,
  GraphQLInterfaceType,
  GraphQLSchema
} from "graphql";

// References
// http://graphql.org/graphql-js/type/#graphqlinterfacetype
// http://graphql.org/graphql-js/type/#graphqluniontype
// https://medium.com/the-graphqlhub/graphql-tour-interfaces-and-unions-7dd5be35de0d


// export const PetType = new GraphQLUnionType({
//   name: 'Pet',
//   // types: [ DogType, CatType ],
//   resolveType(data) {
//     switch (data.type) {
//       case "dog":
//         return DogType;
//       case "cat":
//         return CatType;
//       default:
//         throw "Not a valid Pet type";
//     }
//   },
// });

export const PetType = new GraphQLInterfaceType({
  name: 'Pet',
  fields: {
    type: { type: new GraphQLNonNull(GraphQLString) },
  },
  resolveType(data) {
    switch (data.type) {
      case "dog":
        return DogType;
      case "cat":
        return CatType;
      default:
        throw "Not a valid Pet type";
    }
  },
});



export const DogType = new GraphQLObjectType({
  name: "Dog",
  interfaces: [PetType],
  fields: {
    type: { type: new GraphQLNonNull(GraphQLString) },
    // name: { type: new GraphQLNonNull(GraphQLString) },
    race: { type: new GraphQLNonNull(GraphQLString) },
    // age: { type: new GraphQLNonNull(GraphQLInt) },
  }
});

export const CatType = new GraphQLObjectType({
  name: "Cat",
  interfaces: [PetType],
  fields: {
    type: { type: new GraphQLNonNull(GraphQLString) },
    name: { type: new GraphQLNonNull(GraphQLString) },
    // race: { type: new GraphQLNonNull(GraphQLString) },
    // age: { type: new GraphQLNonNull(GraphQLInt) },
  }
});



export const pets = {
  type: new GraphQLList(PetType),
  resolve() {
    const pets = [
      // Cats
      {type: "cat", name: "Ashes", race: "Siamsese", age: 35},
      {type: "cat", name: "Tiger", race: "Bengal", age: 12},
      {type: "cat", name: "Oscar", race: "Pshynx", age: 27},
      // Dogs
      {type: "dog", name: "Max ", race: "Greyhound", age: 6},
      {type: "dog", name: "Charlie ", race: "Sheherd", age: 57},
      {type: "dog", name: "Buddy", race: "Bulldog", age: 19},
    ];

    // const randomPet = pets[Math.floor(Math.random() * pets.length)]

    return pets;
  }
};


export default new GraphQLSchema({
  types: [
    DogType, 
    CatType
  ],
  query: new GraphQLObjectType({
    name: "Queries",
    fields: {
      pets,
    }
  })
})