refactor(neon,neon_files,neon_notes): improve nullability of SortBoxBuilder

Signed-off-by: Nikolas Rimikis <rimikis.nikolas@gmail.com>

packages/neon/neon/lib/src/sort_box/sort_box_builder.dart

@@ -2,26 +2,39 @@ import 'package:flutter/widgets.dart';
 import 'package:neon/src/settings/models/select_option.dart';
 import 'package:sort_box/sort_box.dart';
 
+/// Signature for a function that creates a widget for a given sorted list.
+///
+/// Used by [SortBoxBuilder] to display a sorted list of items.
+typedef SortBoxWidgetBuilder<T> = Widget Function(BuildContext context, List<T> sorted);
+
+/// Sorted list builder.
+///
+/// Used together with a [SortBox] to sort a given list.
 class SortBoxBuilder<T extends Enum, R> extends StatelessWidget {
-  const SortBoxBuilder({
+  SortBoxBuilder({
     required this.sortBox,
     required this.sortPropertyOption,
     required this.sortBoxOrderOption,
-    required this.input,
+    required final List<R>? input,
     required this.builder,
     super.key,
-  });
+  }) : input = input ?? [];
 
   final SortBox<T, R> sortBox;
   final SelectOption<T> sortPropertyOption;
   final SelectOption<SortBoxOrder> sortBoxOrderOption;
-  final List<R>? input;
-  final Widget Function(BuildContext, List<R>?) builder;
+
+  /// Input list to sort.
+  final List<R> input;
+
+  /// Child builder using the sorted list.
+  final SortBoxWidgetBuilder<R> builder;
 
   @override
   Widget build(final BuildContext context) {
-    if (input == null || (input?.isEmpty ?? false)) {
-      return builder(context, null);
+    if (input.length <= 1) {
+      // input is already sorted.
+      return builder(context, input);
     }
 
     return ValueListenableBuilder<T>(
@@ -31,7 +44,7 @@ class SortBoxBuilder<T extends Enum, R> extends StatelessWidget {
         builder: (final context, final order, final _) {
           final box = Box(property, order);
 
-          return builder(context, sortBox.sort(input!, box));
+          return builder(context, sortBox.sort(input, box));
         },
       ),
     );

packages/neon/neon_files/lib/widgets/browser_view.dart

@@ -60,8 +60,7 @@ class _FilesBrowserViewState extends State<FilesBrowserView> {
                         items: [
                           for (final uploadTask in tasksSnapshot.requireData.whereType<FilesUploadTask>().where(
                                 (final task) =>
-                                    sorted?.where((final file) => _pathMatchesFile(task.path, file.name)).isEmpty ??
-                                    false,
+                                    sorted.where((final file) => _pathMatchesFile(task.path, file.name)).isEmpty,
                               )) ...[
                             FileListTile(
                               bloc: widget.filesBloc,
@@ -73,7 +72,6 @@ class _FilesBrowserViewState extends State<FilesBrowserView> {
                               onPickFile: widget.onPickFile,
                             ),
                           ],
-                          if (sorted != null) ...[
                           for (final file in sorted) ...[
                             if (!widget.onlyShowDirectories || file.isDirectory) ...[
                               Builder(
@@ -103,7 +101,6 @@ class _FilesBrowserViewState extends State<FilesBrowserView> {
                             ],
                           ],
                         ],
-                        ],
                         isLoading: files.isLoading,
                         error: files.error,
                         onRefresh: widget.bloc.refresh,

packages/neon/neon_notes/lib/widgets/notes_view.dart

@@ -31,8 +31,8 @@ class NotesView extends StatelessWidget {
               scrollKey: 'notes-notes',
               withFloatingActionButton: true,
               items: [
-                ...?sortedFavorites,
-                ...?sortedNonFavorites,
+                ...sortedFavorites,
+                ...sortedNonFavorites,
               ],
               isLoading: notes.isLoading,
               error: notes.error,