Pagination with first and after in GraphQL - Mini Project: Build & Apply

Pagination with first and after in GraphQL

📖 Scenario: You are building a simple GraphQL API for a bookstore. The bookstore has many books, and you want to allow users to fetch books in small chunks (pages) to avoid loading too many books at once.

🎯 Goal: Create a GraphQL query that supports pagination using first and after arguments to fetch a limited number of books starting after a given cursor.

📋 What You'll Learn

Create a list of books with exact titles and IDs

Add a first argument to limit the number of books returned

Add an after argument to start fetching books after a specific cursor

Return the books along with cursors for pagination

💡 Why This Matters

🌍 Real World

Pagination is used in APIs to load data in small chunks, improving performance and user experience when dealing with large datasets.

💼 Career

Understanding pagination with cursors is essential for backend developers working with GraphQL APIs or any data service that returns large lists.

1

DATA SETUP: Define the list of books

Create a list called books with these exact entries: { id: "1", title: "Book One" }, { id: "2", title: "Book Two" }, { id: "3", title: "Book Three" }, { id: "4", title: "Book Four" }, { id: "5", title: "Book Five" }.

GraphQL

# Your code here
books = [
    # Add book objects here
]

Hint

Use a list of dictionaries with keys id and title.

2

CONFIGURATION: Define pagination arguments

Create two variables: first set to 2 and after set to "1" to represent fetching 2 books after the book with ID "1".

GraphQL

books = [
    { "id": "1", "title": "Book One" },
    { "id": "2", "title": "Book Two" },
    { "id": "3", "title": "Book Three" },
    { "id": "4", "title": "Book Four" },
    { "id": "5", "title": "Book Five" }
]
# Your code here
first = 
after = 

Hint

Set first to 2 and after to "1" exactly.

3

CORE LOGIC: Implement pagination filtering

Create a variable start_index that finds the index of the book with id equal to after. Then create a variable paginated_books that slices the books list starting after start_index and includes first books.

GraphQL

books = [
    { "id": "1", "title": "Book One" },
    { "id": "2", "title": "Book Two" },
    { "id": "3", "title": "Book Three" },
    { "id": "4", "title": "Book Four" },
    { "id": "5", "title": "Book Five" }
]
first = 2
after = "1"
# Your code here
start_index = 
paginated_books = 

Hint

Use enumerate and next to find the index, then slice the list.

4

COMPLETION: Create the paginated response with cursors

Create a list edges where each item is a dictionary with keys cursor set to the book's id and node set to the book object from paginated_books. Then create a dictionary page_info with endCursor as the last book's id in paginated_books and hasNextPage as True if there are more books after the last one, otherwise False.

GraphQL

books = [
    { "id": "1", "title": "Book One" },
    { "id": "2", "title": "Book Two" },
    { "id": "3", "title": "Book Three" },
    { "id": "4", "title": "Book Four" },
    { "id": "5", "title": "Book Five" }
]
first = 2
after = "1"
start_index = next(i for i, book in enumerate(books) if book["id"] == after)
paginated_books = books[start_index + 1 : start_index + 1 + first]
# Your code here
edges = 
page_info = 

Hint

Use a list comprehension for edges and check length for hasNextPage.