feature: adding dynamic length for day names

lib/src/utils.dart

@@ -1,8 +1,11 @@
 import 'package:intl/intl.dart';
 
 /// Returns the default week days as strings (using intl).
-List<String> defaultWeekDays() =>
-    DateFormat.E().dateSymbols.WEEKDAYS.map((e) => e.substring(0, 3)).toList();
+List<String> defaultWeekDays({int lengthOfDateNames = 3}) => DateFormat.E()
+    .dateSymbols
+    .WEEKDAYS
+    .map((e) => e.substring(0, lengthOfDateNames))
+    .toList();
 
 extension ListUtils on List {
   /// Shifts the list by "amount" places

lib/src/widgets/date_range_picker.dart

@@ -77,8 +77,11 @@ class DayNamesRow extends StatelessWidget {
     Key? key,
     required this.textStyle,
     List<String>? weekDays,
+    int lengthOfDateName = 3,
     int firstDayOfWeek = 0,
-  })  : weekDays = (weekDays ?? defaultWeekDays()).shiftBy(firstDayOfWeek),
+  })  : weekDays =
+            (weekDays ?? defaultWeekDays(lengthOfDateNames: lengthOfDateName))
+                .shiftBy(firstDayOfWeek),
         super(key: key);
 
   final TextStyle textStyle;
@@ -142,12 +145,15 @@ class DateRangePickerWidget extends StatefulWidget {
     this.separatorThickness = 1,
     this.allowSingleTapDaySelection = false,
     this.firstDayOfWeek = 0,
+    this.lengthOfDateName = 3,
   })  : assert(
           firstDayOfWeek >= 0 && firstDayOfWeek <= 6,
           'firstDayOfWeek must be in the range [0..6].',
         ),
         super(key: key);
 
+  final int lengthOfDateName;
+
   /// Called whenever the selected date range is changed.
   final ValueChanged<DateRange?> onDateRangeChanged;
 
@@ -267,6 +273,7 @@ class DateRangePickerWidgetState extends State<DateRangePickerWidget> {
                 delta: calendarController
                     .retrieveDeltaForMonth(widget.firstDayOfWeek),
                 firstDayOfWeek: widget.firstDayOfWeek,
+                lengthOfDateName: widget.lengthOfDateName,
               ),
               if (widget.doubleMonth) ...{
                 if (widget.displayMonthsSeparator)
@@ -338,11 +345,14 @@ class EnrichedMonthWrapWidget extends StatelessWidget {
     required this.days,
     required this.delta,
     this.firstDayOfWeek = 0,
+    this.lengthOfDateName = 3,
   }) : super(key: key);
 
   /// The theme to use for the calendar.
   final CalendarTheme theme;
 
+  final int lengthOfDateName;
+
   /// A callback that is called when the selected date changes.
   final ValueChanged<DateTime> onDateChanged;
 
@@ -364,6 +374,7 @@ class EnrichedMonthWrapWidget extends StatelessWidget {
           DayNamesRow(
             textStyle: theme.dayNameTextStyle,
             firstDayOfWeek: firstDayOfWeek,
+            lengthOfDateName: lengthOfDateName,
           ),
           const SizedBox(height: 16),
           MonthWrapWidget(

test/widgets_test.dart

@@ -19,7 +19,8 @@ void main() {
   });
 
   group('DateRangePickerWidget', () {
-    testWidgets('renders correctly and initializes with initial dateRange',
+    testWidgets(
+        'renders correctly and initializes with initial dateRange render 2 letters names',
         (WidgetTester tester) async {
       final initialDateRange =
           DateRange(DateTime(2023, 1, 1), DateTime(2023, 1, 5));
@@ -29,12 +30,13 @@ void main() {
       await tester.pumpWidget(MaterialApp(
         home: Scaffold(
           body: SizedBox(
-            height: 334,
+            height: 340,
             child: DateRangePickerWidget(
               initialDateRange: initialDateRange,
               minDate: minDate,
               maxDate: maxDate,
               onDateRangeChanged: (DateRange? dateRange) {},
+              lengthOfDateName: 2,
             ),
           ),
         ),
@@ -43,6 +45,38 @@ void main() {
       expect(find.byType(DateRangePickerWidget), findsOneWidget);
       expect(find.byType(MonthSelectorAndDoubleIndicator), findsOneWidget);
       expect(find.byType(DayNamesRow), findsNWidgets(2));
+      expect(find.text('Mo'), findsOneWidget);
+      expect(find.byType(MonthWrapWidget), findsNWidgets(2));
+      expect(find.byType(DayTileWidget), findsWidgets);
+    });
+
+    testWidgets(
+        'renders correctly and initializes with initial dateRange 3 length names',
+        (WidgetTester tester) async {
+      final initialDateRange =
+          DateRange(DateTime(2023, 1, 1), DateTime(2023, 1, 5));
+      final minDate = DateTime(2022, 1, 1);
+      final maxDate = DateTime(2023, 12, 31);
+
+      await tester.pumpWidget(MaterialApp(
+        home: Scaffold(
+          body: SizedBox(
+            height: 340,
+            child: DateRangePickerWidget(
+              initialDateRange: initialDateRange,
+              minDate: minDate,
+              maxDate: maxDate,
+              onDateRangeChanged: (DateRange? dateRange) {},
+              lengthOfDateName: 3,
+            ),
+          ),
+        ),
+      ));
+
+      expect(find.byType(DateRangePickerWidget), findsOneWidget);
+      expect(find.byType(MonthSelectorAndDoubleIndicator), findsOneWidget);
+      expect(find.byType(DayNamesRow), findsNWidgets(2));
+      expect(find.text('Mon'), findsExactly(2));
       expect(find.byType(MonthWrapWidget), findsNWidgets(2));
       expect(find.byType(DayTileWidget), findsWidgets);
     });