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

Input Arguments for Mutations in GraphQL

📖 Scenario: You are building a simple GraphQL API for a bookstore. You want to allow users to add new books to the store by sending a mutation with the book details.

🎯 Goal: Create a GraphQL mutation called addBook that accepts input arguments for the book's title, author, and publishedYear. The mutation should return the added book's details.

📋 What You'll Learn

Define a Book type with fields title, author, and publishedYear.

Create an addBook mutation that takes input arguments title (String!), author (String!), and publishedYear (Int!).

The mutation should return the newly added Book object.

Use input arguments correctly in the mutation definition.

💡 Why This Matters

🌍 Real World

GraphQL mutations with input arguments are used in real APIs to create or update data, such as adding new books to a bookstore database.

💼 Career

Understanding how to define and use input arguments in GraphQL mutations is essential for backend developers working with GraphQL APIs.

1

Define the Book type

Create a GraphQL type called Book with fields title of type String!, author of type String!, and publishedYear of type Int!.

GraphQL

# Define the Book type here
type Book {
  # Your code here
}

Need a hint?

Use type Book { ... } and define each field with its type and exclamation mark for required fields.

2

Add the addBook mutation with input arguments

Add a mutation called addBook inside the type Mutation that accepts three input arguments: title of type String!, author of type String!, and publishedYear of type Int!. The mutation should return a Book.

GraphQL

type Book {
  title: String!
  author: String!
  publishedYear: Int!
}

type Mutation {
  # Your code here
}

Need a hint?

Define type Mutation { addBook(title: String!, author: String!, publishedYear: Int!): Book }.

3

Create an input type for the book details

Create an input type called BookInput with fields title (String!), author (String!), and publishedYear (Int!).

GraphQL

type Book {
  title: String!
  author: String!
  publishedYear: Int!
}

input BookInput {
  # Your code here
}

type Mutation {
  addBook(title: String!, author: String!, publishedYear: Int!): Book
}

Need a hint?

Use input BookInput { ... } to define input fields.

4

Update addBook mutation to use BookInput argument

Modify the addBook mutation to accept a single argument called input of type BookInput! instead of separate arguments. The mutation should still return a Book.

GraphQL

type Book {
  title: String!
  author: String!
  publishedYear: Int!
}

input BookInput {
  title: String!
  author: String!
  publishedYear: Int!
}

type Mutation {
  # Your code here
}

Need a hint?

Change mutation argument to input: BookInput!.