Connection pattern (edges, nodes, pageInfo) in GraphQL - Mini Project: Build & Apply

Build a GraphQL Connection Pattern

📖 Scenario: You are building a GraphQL API for a blog. You want to return a list of posts with pagination support.

🎯 Goal: Create a GraphQL connection pattern with edges, nodes, and pageInfo fields to support paginated queries of blog posts.

📋 What You'll Learn

Define a Post type with id and title fields

Create a PostEdge type with cursor and node fields

Create a PageInfo type with hasNextPage and endCursor fields

Create a PostConnection type with edges (list of PostEdge), nodes (list of Post), and pageInfo fields

💡 Why This Matters

🌍 Real World

GraphQL connection pattern is widely used in APIs to provide efficient and flexible pagination for lists of data, such as posts, comments, or users.

💼 Career

Understanding and implementing connection patterns is essential for backend developers working with GraphQL APIs to build scalable and user-friendly data fetching.

1

Define the Post type

Create a GraphQL type called Post with two fields: id of type ID! and title of type String!.

GraphQL

# Define the Post type with id and title fields
# Your code here

Hint

Use type Post { id: ID! title: String! } syntax.

2

Create the PostEdge type

Create a GraphQL type called PostEdge with two fields: cursor of type String! and node of type Post!.

GraphQL

type Post {
  id: ID!
  title: String!
}

# Define the PostEdge type with cursor and node fields
# Your code here

Hint

Remember to link node to the Post type.

3

Define the PageInfo type

Create a GraphQL type called PageInfo with two fields: hasNextPage of type Boolean! and endCursor of type String (nullable).

GraphQL

type Post {
  id: ID!
  title: String!
}

type PostEdge {
  cursor: String!
  node: Post!
}

# Define the PageInfo type with hasNextPage and endCursor fields
# Your code here

Hint

endCursor can be null, so no exclamation mark.

4

Create the PostConnection type

Create a GraphQL type called PostConnection with three fields: edges as a list of PostEdge (non-nullable items), nodes as a list of Post (non-nullable items), and pageInfo of type PageInfo!.

GraphQL

type Post {
  id: ID!
  title: String!
}

type PostEdge {
  cursor: String!
  node: Post!
}

type PageInfo {
  hasNextPage: Boolean!
  endCursor: String
}

# Define the PostConnection type with edges, nodes, and pageInfo fields
# Your code here

Hint

Use lists with non-nullable items and non-nullable list itself for edges and nodes.