Single endpoint architecture in GraphQL - Mini Project: Build & Apply

Build a Simple GraphQL Single Endpoint

📖 Scenario: You are creating a simple GraphQL API for a bookstore. The API will have a single endpoint that allows clients to query for books and authors.

🎯 Goal: Build a GraphQL schema with a single endpoint that supports querying books and authors with their details.

📋 What You'll Learn

Create a GraphQL type for Book with fields id, title, and authorId.

Create a GraphQL type for Author with fields id and name.

Create a root Query type with fields books and authors that return lists of Book and Author respectively.

Use a single GraphQL endpoint to serve all queries.

💡 Why This Matters

🌍 Real World

Single endpoint GraphQL APIs are used in modern web and mobile apps to fetch exactly the data needed in one request.

💼 Career

Understanding how to design GraphQL schemas and resolvers is essential for backend developers working with APIs.

1

Define Book and Author Types

Create GraphQL types called Book and Author. Book should have fields id (ID!), title (String!), and authorId (ID!). Author should have fields id (ID!) and name (String!).

GraphQL

# Define the Book and Author types
# Your code here

Need a hint?

Use type keyword to define GraphQL object types with their fields and types.

2

Create Root Query Type

Create a root Query type with two fields: books and authors. Both fields should return a list of their respective types: [Book] and [Author].

GraphQL

type Book {
  id: ID!
  title: String!
  authorId: ID!
}

type Author {
  id: ID!
  name: String!
}

# Define the Query type with books and authors fields
# Your code here

Need a hint?

The root Query type defines the entry points for queries. Use square brackets [] to indicate lists.

3

Add Sample Data

Create two arrays called books and authors with sample data. books should have two objects with fields id, title, and authorId. authors should have two objects with fields id and name.

GraphQL

type Book {
  id: ID!
  title: String!
  authorId: ID!
}

type Author {
  id: ID!
  name: String!
}

type Query {
  books: [Book]
  authors: [Author]
}

# Add sample data arrays for books and authors
# Your code here

Need a hint?

Use JavaScript arrays of objects to hold sample data matching the GraphQL types.

4

Add Resolvers for Query Fields

Create a resolvers object with a Query field. Inside Query, add two functions: books and authors. Each function should return the corresponding array: books or authors.

GraphQL

type Book {
  id: ID!
  title: String!
  authorId: ID!
}

type Author {
  id: ID!
  name: String!
}

type Query {
  books: [Book]
  authors: [Author]
}

const books = [
  { id: "1", title: "1984", authorId: "1" },
  { id: "2", title: "Animal Farm", authorId: "1" }
];

const authors = [
  { id: "1", name: "George Orwell" },
  { id: "2", name: "Aldous Huxley" }
];

# Add resolvers object with Query field returning books and authors
# Your code here

Need a hint?

Resolvers connect the schema fields to the data. Use arrow functions returning the sample arrays.