Default resolvers in GraphQL - Mini Project: Build & Apply

GraphQL Default Resolvers Practice

📖 Scenario: You are building a simple GraphQL API for a bookstore. The data is stored in a JavaScript object. You want to use GraphQL's default resolvers to fetch book information without writing custom resolver functions.

🎯 Goal: Create a GraphQL schema with types and queries that use default resolvers to return book data from a JavaScript object.

📋 What You'll Learn

Create a Book type with fields id, title, and author.

Create a Query type with a field books that returns a list of Book.

Create a JavaScript object bookData with exactly three books, each having id, title, and author.

Set up the GraphQL server schema using the default resolvers without writing any custom resolver functions.

Add a query to fetch all books using the default resolver.

💡 Why This Matters

🌍 Real World

GraphQL default resolvers let you quickly build APIs when your data structure matches your schema, saving time and effort.

💼 Career

Understanding default resolvers is essential for backend developers working with GraphQL to efficiently expose data without unnecessary code.

1

Create the book data object

Create a JavaScript constant called bookData that is an array of three objects. Each object must have the exact keys and values: { id: '1', title: '1984', author: 'George Orwell' }, { id: '2', title: 'Brave New World', author: 'Aldous Huxley' }, and { id: '3', title: 'Fahrenheit 451', author: 'Ray Bradbury' }.

GraphQL

# Your code here

Need a hint?

Use const bookData = [ ... ] with three objects inside the array.

2

Define the GraphQL schema types

Create a GraphQL schema string called typeDefs that defines a Book type with fields id (ID!), title (String!), and author (String!). Also define a Query type with a field books that returns a list of Book (use square brackets).

GraphQL

const bookData = [
  { id: '1', title: '1984', author: 'George Orwell' },
  { id: '2', title: 'Brave New World', author: 'Aldous Huxley' },
  { id: '3', title: 'Fahrenheit 451', author: 'Ray Bradbury' }
];

# Your code here

Need a hint?

Use backticks to create a multi-line string for typeDefs. Define the Book and Query types exactly as described.

3

Set up the resolver map using default resolvers

Create a JavaScript object called resolvers with a Query field. Inside Query, create a field books that returns the bookData array. Do not write any custom resolver functions for the Book fields.

GraphQL

const bookData = [
  { id: '1', title: '1984', author: 'George Orwell' },
  { id: '2', title: 'Brave New World', author: 'Aldous Huxley' },
  { id: '3', title: 'Fahrenheit 451', author: 'Ray Bradbury' }
];

const typeDefs = `
  type Book {
    id: ID!
    title: String!
    author: String!
  }

  type Query {
    books: [Book]
  }
`;

# Your code here

Need a hint?

Define resolvers as an object with a Query property. Inside Query, add a books field that returns bookData.

4

Complete the GraphQL server setup

Create an Apollo Server instance called server using typeDefs and resolvers. Export the server as the default export.

GraphQL

const bookData = [
  { id: '1', title: '1984', author: 'George Orwell' },
  { id: '2', title: 'Brave New World', author: 'Aldous Huxley' },
  { id: '3', title: 'Fahrenheit 451', author: 'Ray Bradbury' }
];

const typeDefs = `
  type Book {
    id: ID!
    title: String!
    author: String!
  }

  type Query {
    books: [Book]
  }
`;

const resolvers = {
  Query: {
    books: () => bookData
  }
};

# Your code here

Need a hint?

Import ApolloServer, create a new server with typeDefs and resolvers, then export it as default.