诱人的 GraphQL & React & Apollo 实战视频教程 #18 更新 Resolve

const graphql = require('graphql');
const _ = require('lodash');
const Book = require('../models/book');
const Author = require('../models/author');

const {
  GraphQLObjectType,
  GraphQLString,
  GraphQLSchema,
  GraphQLID,
  GraphQLInt,
  GraphQLList
} = require('graphql');

// 书是属于作者，作者有很多书, 一对多
// 查询一个作者的书
// 查询一本书的作者
// const books = [
//   { name: "算法导论", genre: "计算机科学", id: "1", authorId: '1' },
//   { name: "人性的弱点", genre: "社交", id: "2", authorId: '2' },
//   { name: "明朝那些事儿", genre: "历史", id: "3", authorId: '3' },
//   { name: "诱人的 GraqhQL 教程", genre: "计算机科学", id: "4", authorId: '1' },
//   { name: "诱人的 mobx 教程", genre: "计算机科学", id: "5", authorId: '2' },
// ];
//
// const authors = [
//   { name: "hfpp2012", age: 27, id: "1" },
//   { name: "rails365", age: 30, id: "2" },
//   { name: "lili", age: 21, id: "3" }
// ];

const BookType = new GraphQLObjectType({
  name: "Book",
  fields: () => ({
    id: { type: GraphQLID },
    name: { type: GraphQLString },
    genre: { type: GraphQLString },
    author: {
      type: AuthorType,
      resolve(parent, args) {
        // return _.find(authors, { id: parent.authorId })
        return Author.findById(parent.authorId);
      }
    }
  })
})

const AuthorType = new GraphQLObjectType({
  name: "Author",
  fields: () => ({
    id: { type: GraphQLID },
    name: { type: GraphQLString },
    age: { type: GraphQLInt },
    books: {
      type: new GraphQLList(BookType),
      resolve(parent, args) {
        // return _.filter(books, { authorId: parent.id })
        return Book.find({ authorId: parent.id });
      }
    }
  })
})

const RootQuery = new GraphQLObjectType({
  name: "RootQueryType",
  fields: {
    book: {
      type: BookType,
      args: { id: { type: GraphQLID } },
      resolve(parent, args) {
        // 从哪里得到数据，比如数据库或其他来源
        // Mongodb mysql postgresql
        // console.log(typeof(args.id));
        // return _.find(books, { id: args.id })
        return Book.findById(args.id);
      }
    },
    author: {
      type: AuthorType,
      args: { id: { type: GraphQLID } },
      resolve(parent, args) {
        // return _.find(authors, { id: args.id })
        return Author.findById(args.id);
      }
    },
    books: {
      type: GraphQLList(BookType),
      resolve(parent, args) {
        // return books;
        return Book.find({});
      }
    },
    authors: {
      type: GraphQLList(AuthorType),
      resolve(parent, args) {
        // return authors;
        return Author.find({});
      }
    }
  }
})

const Mutation = new GraphQLObjectType({
  name: "Mutation",
  fields: {
    addAuthor: {
      type: AuthorType,
      args: {
        name: { type: GraphQLString },
        age: { type: GraphQLInt }
      },
      resolve(parent, args) {
        let author = new Author({
          name: args.name,
          age: args.age
        })

        return author.save();
      }
    },
    addBook: {
      type: BookType,
      args: {
        name: { type: GraphQLString },
        genre: { type: GraphQLString },
        authorId: { type: GraphQLID }
      },
      resolve(parent, args) {
        let book = new Book({
          name: args.name,
          genre: args.genre,
          authorId: args.authorId
        });
        return book.save();
      }
    }
  }
})

module.exports = new GraphQLSchema({
  query: RootQuery,
  mutation: Mutation
});

{
  book(id: "5bff4b33024d736c42697a64") {
    name
    id
    genre
    author {
      name
      books {
        name
      }
    }
  }
}

{
  author(id: "5bfea882bc5433700ca5dae7") {
    name
    age
    books {
      name
      genre
    }
  }
}

{
  books {
    name
    genre
    id
  }
}

{
  books {
    name
    genre
    id
    author {
      name
      age
      books {
        name
      }
    }
  }
}

{
  authors {
    name
    age
    id
    books {
      name
      genre
      id
      author {
        name
        age
      }
    }
  }
}