Input type for complex arguments in GraphQL - Mini Project: Build & Apply

GraphQL Input Type for Complex Arguments

📖 Scenario: You are building a simple GraphQL API for a book store. You want to allow users to add new books with detailed information like title, author, and publication year.

🎯 Goal: Create a GraphQL input type called BookInput to accept complex arguments for adding a new book. Then use this input type in a mutation called addBook.

📋 What You'll Learn

Create an input type named BookInput with fields title (String), author (String), and year (Int).

Define a mutation addBook that takes one argument book of type BookInput.

The mutation should return a Book type with the same fields.

Use exact names: BookInput, addBook, book, Book.

💡 Why This Matters

🌍 Real World

GraphQL input types let APIs accept complex data structures, like objects with multiple fields, making it easier to send detailed information in one request.

💼 Career

Understanding input types and mutations is essential for backend developers working with GraphQL APIs to create flexible and maintainable data operations.

1

Define the Book type

Create a GraphQL type called Book with fields title (String), author (String), and year (Int).

GraphQL

# Define the Book type with title, author, and year fields

Need a hint?

Use type Book { ... } syntax to define the Book type with the specified fields.

2

Create the BookInput input type

Create a GraphQL input type called BookInput with fields title (String), author (String), and year (Int).

GraphQL

type Book {
  title: String
  author: String
  year: Int
}

# Define the BookInput input type with title, author, and year fields

Need a hint?

Use input BookInput { ... } syntax similar to the Book type.

3

Define the addBook mutation

Define a mutation called addBook that takes one argument book of type BookInput and returns a Book type.

GraphQL

type Book {
  title: String
  author: String
  year: Int
}

input BookInput {
  title: String
  author: String
  year: Int
}

# Define the addBook mutation with book argument of type BookInput

Need a hint?

Use type Mutation { addBook(book: BookInput): Book } syntax to define the mutation.

4

Complete the schema with Query and Mutation

Add a root type Query with a dummy field _empty of type String to complete the schema. Keep the Mutation type as defined.

GraphQL

type Book {
  title: String
  author: String
  year: Int
}

input BookInput {
  title: String
  author: String
  year: Int
}

type Mutation {
  addBook(book: BookInput): Book
}

# Add a root Query type with _empty field

Need a hint?

GraphQL schemas need a root Query type. Add type Query { _empty: String } to complete the schema.