[CHORES] Clean code

lib/Component/router.dart

@@ -155,7 +155,7 @@ class Router {
                   RepositoryProvider.of<DependenciesRepositories>(
                       context)
                       .dio),
-              child: Programs()
+              child: const Programs()
             ));
 
       case detailProgramPage:

lib/Pages/Program/bloc_program/program_bloc.dart

@@ -60,7 +60,7 @@ class ProgramBloc extends Bloc<ProgramEvent, ProgramState> {
       }
     } else if ((event is FetchProgramByStatus) && !_hasReachedMaxSorted(currentState)) {
       try {
-        var programs =
+        final programs =
         await programRepository.fetchProgram(page: currentState.page + 1);
         if (currentState is ListProgramsLoaded || currentState is InitialListProgramState) {
           programs.results.sort((a,b) => b.endDateTime.compareTo(a.endDateTime));

lib/Pages/Program/program_page.dart

@@ -69,17 +69,17 @@ class _ProgramsState extends State<Programs> {
                 ),
               ),
               bottomNavigationBar: Container(
-                margin: EdgeInsets.symmetric(horizontal: 25.0),
+                margin: const EdgeInsets.symmetric(horizontal: 25.0),
                 child: Wrap(children: [
-                  Padding(
-                    padding: const EdgeInsets.only(top: 20),
+                  const Padding(
+                    padding: EdgeInsets.only(top: 20),
                     child: Text('Urutkan Berdasarkan:',
                       style: TextStyle(fontSize: 16.0),),
                   ),
                   GestureDetector(
                       onTap: () {
                         setState(() {
-                          programList = _ListProgramSortStatus();
+                          programList = const _ListProgramSortStatus();
                         });
                       },
                       child: FilterButton(sort: 'Status')
@@ -87,7 +87,7 @@ class _ProgramsState extends State<Programs> {
                   GestureDetector(
                       onTap: () {
                         setState(() {
-                          programList = _ListProgram();
+                          programList = const _ListProgram();
                         });
                       },
                       child: FilterButton(sort: 'Tanggal')
@@ -336,7 +336,7 @@ class ProgramCard extends StatelessWidget {
 
 class _ProgramDescription extends StatelessWidget {
   final Program program;
-  _ProgramDescription({Key key, @required this.program})
+  const _ProgramDescription({Key key, @required this.program})
       : assert(program != null),
         super(key: key);
 
@@ -383,7 +383,7 @@ class _ProgramDescription extends StatelessWidget {
                             ),
                             if ( program.endDateTime != null &&
                             program.endDateTime.compareTo(CustomizableDateTime.current) < 1)
-                              Text(
+                              const Text(
                                 'Selesai',
                                 style: TextStyle(fontWeight: FontWeight.bold),
                               )
@@ -429,7 +429,9 @@ class _DonasiButton extends StatelessWidget {
 
 class FilterButton extends StatelessWidget {
   final String sort;
-  FilterButton({Key key, @required this.sort});
+  FilterButton({Key key, @required this.sort})
+      : assert(sort != null),
+        super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -442,7 +444,7 @@ class FilterButton extends StatelessWidget {
       child: Padding(
         padding: const EdgeInsets.symmetric(vertical: 10.0, horizontal: 10.0),
         child: Text(sort,
-          style: TextStyle(color: Colors.white),
+          style: const TextStyle(color: Colors.white),
         ),
       ),
     );