A BLoC library for loading data from an api end-point with filtering and pagination.

The idea for this library is to convert the data loaded from an API into a BLoC to avoid boilerplate, but at the same time keeping things very simple and generic.

The base classes are DataCubt<T,F> where T is the type of the data element and F is a class for thr API filtering. It is implemented via freezed union of Data, Empty, Loading, Error.

Then, ListCubit<T,F> extends DataCubit<List<T>,F to provide a shorthand for loading list of items.

Further, ContinousListBloc<T,F> extends ListCubit<T,F> to facilitate implementing continuous lists. It requires OffsetLimitFilter to be implemented by F to be able to load extra data in the end of the list.

Finally, PaginatedCubit<T,F> extends DataCubit<ListPage<T,F> to provide pagination and switching between bates.

If you have an API instance that does not use filtering, you can replace the filter class with Object.

All blocs are expecting to be initialized with a variant of Future<T> loader([F? filter]) to get the data from the api and each is slightly different.

The filters can extend Object or any other class however freezed is quite useful for this as this allows re-building filters based on existing ones quite easily.

Usage

A simple usage example:

import 'packages:list_bloc.dart';

// Can be as complex as the API supports
class ItemFilter {
    enum fruits, vegetables;
}
class Item {
    int type;
    int value;
}

typedef FruitBloc = ListBloc<Item, ItemFilter>;
typedef FruitState = Data<List<Item>, ItemFilter>;

Future List<Item> loader([ItemFilter? filter]) async => api.....

main() {
    final bloc = FruitBloc(loader);

    bloc.load(ItemFilter.fruits);
...
    BlocBuilder<FruitBloc, FruitState>(
        bloc: bloc,
        builder: (context, state) {
            for(var item in state.data) {
                    ...
            }
        } 
}

TODO: PaginatedBloc example ListPage class explanation

Features and bugs

Please file feature requests and bugs at the issue tracker.