import { ApolloServer , gql } from "apollo-server" ; let books = [ { id : "1" , title : "Harry Potter and the Chamber of Secrets" , author : "J.K. Rowling" } , { id : "2" , title : "Jurassic Park" , author : "Michael Crichton" } ] ; const typeDefs = gql `
  type Book {
    id: ID!
    title: String!
    author: String!
  }

  type Mutation {
    createBook(title: String!, author: String!): Book!
    updateBook(id: String!, title: String!, author: String!): Book!
    deleteBook(id: String!): Boolean!
  }

  type Query {
    books: [Book!]!
  }
` ; type Resolver = ( parent : any , args : any ) => any ; const resolvers = { Mutation : { createBook : ( _ , { title , author } ) => { const book = { id : `${ books . length + 1 }` , title , author } ; books . push ( book ) ; return book ; } , updateBook : ( _ , book ) => { books = books . map ( x => ( x . id === book . id ? book : x ) ) ; return book ; } , deleteBook : ( _ , { id } ) => { books = books . filter ( x => x . id !== id ) ; return true ; } } , Query : { books : ( ) => books } } ; const server = new ApolloServer ( { typeDefs , resolvers } ) ; server . listen ( ) . then ( ( { url } ) => { console . log ( `🚀  Server ready at ${ url }` ) ; } ) ;