Moved autosave functionality to LocalStorage singleton

Author: Levi-Lesches

pkgs/dartpad_ui/lib/editor/editor.dart

@@ -12,6 +12,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:web/web.dart' as web;
 
+import '../local_storage.dart';
 import '../model.dart';
 import 'codemirror.dart';
 
@@ -185,7 +186,7 @@ class _EditorWidgetState extends State<EditorWidget> implements EditorService {
   void _autosave([Timer? timer]) {
     final content = widget.appModel.sourceCodeController.text;
     if (content.isEmpty) return;
-    web.window.localStorage.setItem('user_input', content);
+    LocalStorage.instance.saveUserCode(content);
   }
 
   void _platformViewCreated(int id, {required bool darkMode}) {

pkgs/dartpad_ui/lib/local_storage.dart

@@ -0,0 +1,18 @@
+// Copyright (c) 2024, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:web/web.dart' as web;
+
+const _userInputKey = 'user_';
+
+class LocalStorage {
+  static final instance = LocalStorage._();
+
+  LocalStorage._();
+
+  void saveUserCode(String code) =>
+      web.window.localStorage.setItem(_userInputKey, code);
+
+  String? getUserCode() => web.window.localStorage.getItem(_userInputKey);
+}

pkgs/dartpad_ui/lib/main.dart

@@ -15,7 +15,6 @@ import 'package:provider/provider.dart';
 import 'package:split_view/split_view.dart';
 import 'package:url_launcher/url_launcher.dart' as url_launcher;
 import 'package:vtable/vtable.dart';
-import 'package:web/web.dart' as web;
 
 import 'console.dart';
 import 'docs.dart';
@@ -24,6 +23,7 @@ import 'embed.dart';
 import 'execution/execution.dart';
 import 'extensions.dart';
 import 'keys.dart' as keys;
+import 'local_storage.dart';
 import 'model.dart';
 import 'problems.dart';
 import 'samples.g.dart';
@@ -273,25 +273,27 @@ class _DartPadMainPageState extends State<DartPadMainPage>
     );
 
     appServices.populateVersions();
-    appServices
-        .performInitialLoad(
-            gistId: widget.gistId,
-            sampleId: widget.builtinSampleId,
-            flutterSampleId: widget.flutterSampleId,
-            channel: widget.initialChannel,
-            fallbackSnippet: web.window.localStorage.getItem('user_input') ??
-                Samples.defaultSnippet())
-        .then((value) {
-      // Start listening for inject code messages.
-      handleEmbedMessage(appServices, runOnInject: widget.runOnLoad);
-      if (widget.runOnLoad) {
-        appServices.performCompileAndRun();
-      }
-    });
+    _initAppServices();
 
     appModel.compilingBusy.addListener(_handleRunStarted);
   }
 
+  Future<void> _initAppServices() async {
+    await appServices.performInitialLoad(
+      gistId: widget.gistId,
+      sampleId: widget.builtinSampleId,
+      flutterSampleId: widget.flutterSampleId,
+      channel: widget.initialChannel,
+      fallbackSnippet:
+          LocalStorage.instance.getUserCode() ?? Samples.defaultSnippet(),
+    );
+    // Start listening for inject code messages.
+    handleEmbedMessage(appServices, runOnInject: widget.runOnLoad);
+    if (widget.runOnLoad) {
+      appServices.performCompileAndRun();
+    }
+  }
+
   @override
   void dispose() {
     appModel.compilingBusy.removeListener(_handleRunStarted);