opt.: replace first with firstOrNull

lib/data/model/app/backup.dart

@@ -70,7 +70,7 @@ class Backup {
 
   Backup.loadFromStore()
       : version = backupFormatVersion,
-        date = DateTime.now().toString().split('.').first,
+        date = DateTime.now().toString().split('.').firstOrNull ?? '',
         spis = Stores.server.fetch(),
         snippets = Stores.snippet.fetch(),
         keys = Stores.key.fetch(),

lib/data/model/server/cpu.dart

@@ -92,7 +92,8 @@ class OneTimeCpuStatus extends TimeSeqIface<OneTimeCpuStatus> {
 
     for (var item in raw.split('\n')) {
       if (item == '') break;
-      final id = item.split(' ').first;
+      final id = item.split(' ').firstOrNull;
+      if (id == null) continue;
       final matches = item.replaceFirst(id, '').trim().split(' ');
       cpus.add(
         OneTimeCpuStatus(

lib/data/model/server/temp.dart

@@ -50,7 +50,7 @@ class Temperatures {
         return _map[key];
       }
     }
-    return _map.values.first;
+    return _map.values.firstOrNull;
   }
 }
 

lib/view/page/ping.dart

@@ -148,7 +148,7 @@ class _PingPageState extends State<PingPage>
     if (result.results == null || result.results!.isEmpty) {
       return '$ip - ${l10n.noResult}';
     }
-    final ttl = result.results?.first.ttl ?? unknown;
+    final ttl = result.results?.firstOrNull?.ttl ?? unknown;
     final loss = result.statistic?.loss ?? unknown;
     final min = result.statistic?.min ?? unknown;
     final max = result.statistic?.max ?? unknown;

lib/view/page/ssh/page.dart

@@ -287,7 +287,8 @@ class _SSHPageState extends State<SSHPage> with AutomaticKeepAliveClientMixin {
         );
         if (snippets == null || snippets.isEmpty) return;
 
-        final snippet = snippets.first;
+        final snippet = snippets.firstOrNull;
+        if (snippet == null) return;
         _terminal.textInput(snippet.script);
         _terminal.keyInput(TerminalKey.enter);
         break;

lib/view/page/storage/sftp.dart

@@ -665,7 +665,7 @@ class _SftpPageState extends State<SftpPage> with AfterLayoutMixin {
           /// Issue #97
           /// In order to compatible with the Synology NAS
           /// which not has '.' and '..' in listdir
-          if (fs.isNotEmpty && fs.first.filename == '.') {
+          if (fs.isNotEmpty && fs.firstOrNull?.filename == '.') {
             fs.removeAt(0);
           }
 
@@ -673,7 +673,7 @@ class _SftpPageState extends State<SftpPage> with AfterLayoutMixin {
           /// Due to [WillPopScope] added in this page
           /// There is no need to keep '..' folder in listdir
           /// So remove it
-          if (fs.isNotEmpty && fs.first.filename == '..') {
+          if (fs.isNotEmpty && fs.firstOrNull?.filename == '..') {
             fs.removeAt(0);
           }
           if (mounted) {

lib/view/widget/server_func_btns.dart

@@ -135,8 +135,8 @@ void _onTapMoreBtns(
         name: (e) => e.name,
       );
       if (snippets == null || snippets.isEmpty) return;
-      final snippet = snippets.first;
-
+      final snippet = snippets.firstOrNull;
+      if (snippet == null) return;
       AppRoute.ssh(spi: spi, initCmd: snippet.fmtWith(spi)).checkGo(
         context: context,
         check: () => _checkClient(context, spi.id),