when<R> method

R when<R>({ required R loading(), required R success(T data), required R error(Object error), required R empty(), R custom()?, })

Exhaustive pattern matching — all cases must be handled.

status.when(
  loading: () => showSpinner(),
  success: (data) => showContent(data),
  error: (err) => showError(err),
  empty: () => showEmpty(),
);

Implementation

R when<R>({
  required R Function() loading,
  required R Function(T data) success,
  required R Function(Object error) error,
  required R Function() empty,
  R Function()? custom,
}) {
  if (this is SuccessStatus<T>) {
    return success((this as SuccessStatus<T>).data);
  } else if (this is ErrorStatus<T, Object>) {
    return error((this as ErrorStatus<T, Object>).error ?? 'Unknown error');
  } else if (this is LoadingStatus<T>) {
    return loading();
  } else if (this is EmptyStatus<T>) {
    return empty();
  } else {
    return (custom ?? empty)();
  }
}