Advanced Pagination - Relay

import DocsRating from '@site/src/core/DocsRating'; import {OssOnly, FbInternalOnly} from 'docusaurus-plugin-internaldocs-fb/internal';

In this section we're going to cover how to implement more advanced pagination use cases than the default cases covered by usePaginationFragment.

Pagination Over Multiple Connections

If you need to paginate over multiple connections within the same component, you can use usePaginationFragment multiple times:

import type {CombinedFriendsListComponent_user$key} from 'CombinedFriendsListComponent_user.graphql';
import type {CombinedFriendsListComponent_viewer$key} from 'CombinedFriendsListComponent_viewer.graphql';

const React = require('React');

const {graphql, usePaginationFragment} = require('react-relay');

type Props = {
  user: CombinedFriendsListComponent_user$key,
  viewer: CombinedFriendsListComponent_viewer$key,
};

function CombinedFriendsListComponent(props: Props) {

  const {data: userData, ...userPagination} = usePaginationFragment(
    graphql`
      fragment CombinedFriendsListComponent_user on User {
        name
        friends
          @connection(
            key: "CombinedFriendsListComponent_user_friends_connection"
          ) {
          edges {
            node {
              name
              age
            }
          }
        }
      }
    `,
    props.user,
  );

  const {data: viewerData, ...viewerPagination} = usePaginationFragment(
    graphql`
      fragment CombinedFriendsListComponent_user on Viewer {
        actor {
          ... on User {
            name
            friends
              @connection(
                key: "CombinedFriendsListComponent_viewer_friends_connection"
              ) {
              edges {
                node {
                  name
                  age
                }
              }
            }
          }
        }
      }
    `,
    props.viewer,
  );

  return (...);
}

However, we recommend trying to keep a single connection per component, to keep the components easier to follow.

Bi-directional Pagination

In the Pagination section we covered how to use usePaginationFragment to paginate in a single "forward" direction. However, connections also allow paginating in the opposite "backward" direction. The meaning of "forward" and "backward" directions will depend on how the items in the connection are sorted, for example "forward" could mean more recent*, and "backward"* could mean less recent.

Regardless of the semantic meaning of the direction, Relay also provides the same APIs to paginate in the opposite direction, using usePaginationFragment, as long as the before and last connection arguments are also used along with after and first:

import type {FriendsListComponent_user$key} from 'FriendsListComponent_user.graphql';

const React = require('React');
const {Suspense} = require('React');

const {graphql, usePaginationFragment} = require('react-relay');

type Props = {
  userRef: FriendsListComponent_user$key,
};

function FriendsListComponent(props: Props) {
  const {
    data,
    loadPrevious,
    hasPrevious,
    // ... forward pagination values
  } = usePaginationFragment(
    graphql`
      fragment FriendsListComponent_user on User {
        name
        friends(after: $after, before: $before, first: $first, last: $last)
          @connection(key: "FriendsListComponent_user_friends_connection") {
          edges {
            node {
              name
              age
            }
          }
        }
      }
    `,
    userRef,
  );

  return (
    <>
      <h1>Friends of {data.name}:</h1>
      <List items={data.friends?.edges.map(edge => edge.node)}>
        {node => {
          return (
            <div>
              {node.name} - {node.age}
            </div>
          );
        }}
      </List>

      {hasPrevious ? (
        <Button onClick={() => loadPrevious(10)}>
          Load more friends
        </Button>
      ) : null}
    </>
  );
}

The APIs for both "forward" and "backward" are exactly the same, they're only named differently. When paginating forward, then the after and first connection arguments will be used, when paginating backward, the before and last connection arguments will be used.
Note that the primitives for both "forward" and "backward" pagination are exposed from a single call to usePaginationFragment, so both "forward" and "backward" pagination can be performed simultaneously in the same component.