README.md

swift-graphql-pagination

A Swift implementation of the GraphQL Cursor Connections Specification.

Purpose

This package provides an alternative to the pagination/connection tools provided by Graphiti. Benefits include:

• Create your own connection/edge types that expose additional data
• An opaque Cursor type that supports identity-based or index-based cursors
• Converts GraphQL pagination model to offset pagination to give to your database, elasticsearch, etc.
• Offset pagination performs a "plus two" algorithm to efficiently calculate hasNextPage and hasPreviousPage

Example

Add pagination to any arguments.

/// This supports forward and backward pagination. We could use `GraphForwardPaginatable` to simplify.
struct PeopleArguments: GraphPaginatable {
  // ... other inputs
  var first: Int?
  var after: Cursor?
  var last: Int?
  var before: Cursor?
}

Use pagination.

func people(context: Context, arguments: PeopleArguments) async throws -> BasicConnection<Person> {
  // Extract offset and count from the input, and query the database.
  let offsetPagination = arguments.pagination.makeOffsetPagination()
  let people = try await Person.all(
    offset: offsetPagination.offset,
    count: offsetPagination.count
  )
  // Create a connection data structure converting people into edges
  // with index-based cursors.
  return BasicConnection(
    nodes: people,
    pagination: arguments.pagination,
    cursor: .index
  )
}

GraphQL

{
  "people": {
    "edges": [
      {
        "cursor": "MA==",
        "node": { }
      },
      {
        "cursor": "MQ==", 
        "node": {  }
      }
    ],
    "pageInfo": {
      "hasPreviousPagePage": false,
      "hasNextPage": true,
      "startCursor": "MA==",
      "startCursor": "MQ=="
    }
  }
}

License

MIT