Infinite Queries

Infinite queries allow you to handle paginated data, such as “Load More” lists or infinite scrolls.

Usage

Since Fasq currently provides the raw logic for infinite queries, you can use it with a standard StreamBuilder.

// 1. Define the fetch function
Future<List<Post>> fetchPosts(int page) async {
  return api.getPosts(page: page);
}

// 2. Create the InfiniteQuery
final query = QueryClient().getInfiniteQuery<List<Post>, int>(
  'posts'.toQueryKey(),
  (page) => fetchPosts(page),
  options: InfiniteQueryOptions(
     // Define how to get the next page param
     getNextPageParam: (pages, lastPage) {
       return pages.length; // Simple page number logic
     },
  ),
);

// 3. Use standard StreamBuilder
class PostList extends StatefulWidget {
  @override
  _PostListState createState() => _PostListState();
}

class _PostListState extends State<PostList> {
  @override
  void initState() {
    super.initState();
    // Start listening to data
    query.addListener();
    // Fetch first page if needed
    if (query.state.pages.isEmpty) {
        query.fetchNextPage(0);
    }
  }

  @override
  void dispose() {
    query.removeListener();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return StreamBuilder(
      stream: query.stream,
      initialData: query.state,
      builder: (context, snapshot) {
        final state = snapshot.data!;

        // Flatten pages into a single list
        final posts = state.pages.expand((page) => page.data ?? []).toList();

        return ListView.builder(
          itemCount: posts.length + 1,
          itemBuilder: (context, index) {
            if (index == posts.length) {
              // Load more button
              return ElevatedButton(
                onPressed: state.isFetchingNextPage
                   ? null
                   : () => query.fetchNextPage(),
                child: state.isFetchingNextPage
                   ? const CircularProgressIndicator()
                   : const Text('Load More'),
              );
            }
            return ListTile(title: Text(posts[index].title));
          },
        );
      },
    );
  }
}

API

InfiniteQueryOptions

Property	Description
getNextPageParam	Function to calculate the next page parameter given the current pages. Return null to indicate no more pages.
getPreviousPageParam	Function to calculate the previous page parameter.
maxPages	Maximum number of pages to keep in memory (auto-garbage collection for lists).

InfiniteQueryState

Property	Description
pages	List of Page<TData, TParam> objects containing your data.
hasNextPage	Boolean indicating if there is more data to fetch.
isFetchingNextPage	True if currently fetching the next page.