Fix web problems

app/lib/api/save.dart

@@ -1,36 +1,17 @@
-import 'dart:io';
-
-import 'package:file_selector/file_selector.dart' as fs;
-import 'package:flutter/foundation.dart';
+import 'package:butterfly/api/save_stub.dart'
+    if (dart.library.io) 'package:butterfly/api/save_io.dart'
+    if (dart.library.js) 'package:butterfly/api/save_html.dart' as save;
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
-import 'package:share_plus/share_plus.dart';
 
 Future<void> exportFile(
   BuildContext context,
   List<int> bytes,
   String fileExtension,
   String mimeType,
-) async {
-  final file = fs.XFile.fromData(Uint8List.fromList(bytes),
-      mimeType: mimeType, name: 'output.$fileExtension');
-  if (kIsWeb || Platform.isAndroid || Platform.isIOS) {
-    Share.shareXFiles([file]);
-    return;
-  }
-  final result = await fs.getSaveLocation(
-    acceptedTypeGroups: [
-      fs.XTypeGroup(
-        label: AppLocalizations.of(context).export,
-        extensions: [fileExtension],
-        mimeTypes: [mimeType],
-      ),
-    ],
-  );
-  if (result == null) return;
-  await file.saveTo(result.path);
-}
+) =>
+    save.exportFile(context, bytes, fileExtension, mimeType);
 
 Future<void> exportSvg(BuildContext context, String data) =>
     exportFile(context, data.codeUnits, 'svg', 'image/svg');

app/lib/api/save_html.dart

@@ -0,0 +1,20 @@
+// ignore_for_file: avoid_web_libraries_in_flutter
+
+import 'dart:html';
+
+import 'package:flutter/material.dart';
+
+Future<void> exportFile(
+  BuildContext context,
+  List<int> bytes,
+  String fileExtension,
+  String mimeType,
+) async {
+  final a = document.createElement('a') as AnchorElement;
+  // Create data URL
+  final blob = Blob([bytes], 'text/plain');
+  final url = Url.createObjectUrl(blob);
+  a.href = url;
+  a.download = 'output.$fileExtension';
+  a.click();
+}

app/lib/api/save_io.dart

@@ -0,0 +1,32 @@
+import 'dart:io';
+import 'dart:typed_data';
+
+import 'package:file_selector/file_selector.dart' as fs;
+import 'package:flutter/material.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
+import 'package:share_plus/share_plus.dart';
+
+Future<void> exportFile(
+  BuildContext context,
+  List<int> bytes,
+  String fileExtension,
+  String mimeType,
+) async {
+  final file = fs.XFile.fromData(Uint8List.fromList(bytes),
+      mimeType: mimeType, name: 'output.$fileExtension');
+  if (Platform.isAndroid || Platform.isIOS) {
+    Share.shareXFiles([file]);
+    return;
+  }
+  final result = await fs.getSaveLocation(
+    acceptedTypeGroups: [
+      fs.XTypeGroup(
+        label: AppLocalizations.of(context).export,
+        extensions: [fileExtension],
+        mimeTypes: [mimeType],
+      ),
+    ],
+  );
+  if (result == null) return;
+  await file.saveTo(result.path);
+}

app/lib/api/save_stub.dart

@@ -0,0 +1,8 @@
+import 'package:flutter/material.dart';
+
+Future<void> exportFile(
+  BuildContext context,
+  List<int> bytes,
+  String fileExtension,
+  String mimeType,
+) async {}

app/web/index.html

@@ -31,7 +31,7 @@
   <link rel="manifest" href="manifest.json">
 
 
-  <script src="pdf.js/pdf.min.js"></script>
+  <script src="pdf.js/pdf.min.js" type="module"></script>
   <script type="text/javascript">
       pdfjsLib.GlobalWorkerOptions.workerSrc = "pdf.js/pdf.worker.min.js";
   </script>