update, test stub

flutter_cache_manager/lib/src/storage/file_system/file_system_web.dart

@@ -2,9 +2,11 @@ import 'package:file/file.dart' show File;
 import 'package:file/memory.dart';
 import 'package:flutter_cache_manager/src/storage/file_system/file_system.dart';
 
-// Export web-specific implementations
-export 'indexed_db_file.dart';
-export 'indexed_db_file_system.dart';
+// Web-specific implementations: export on web only, export stubs elsewhere
+export 'indexed_db_file_stub.dart'
+    if (dart.library.js_interop) 'indexed_db_file.dart';
+export 'indexed_db_file_system_stub.dart'
+    if (dart.library.js_interop) 'indexed_db_file_system.dart';
 
 class MemoryCacheSystem implements FileSystem {
   final directory = MemoryFileSystem().systemTempDirectory.createTemp('cache');

flutter_cache_manager/lib/src/storage/file_system/indexed_db_file_stub.dart

@@ -0,0 +1,175 @@
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:file/file.dart';
+
+// Non-web stub to satisfy conditional export when js_interop is unavailable
+class IndexedDbFile implements File {
+  IndexedDbFile(String path, String dbName);
+
+  @override
+  File get absolute => this;
+
+  @override
+  Future<File> copy(String newPath) => _unsupported();
+
+  @override
+  File copySync(String newPath) => _throw();
+
+  @override
+  Future<File> create({bool recursive = false, bool exclusive = false}) =>
+      _unsupported();
+
+  @override
+  void createSync({bool recursive = false, bool exclusive = false}) => _throw();
+
+  @override
+  Future<FileSystemEntity> delete({bool recursive = false}) => _unsupported();
+
+  @override
+  void deleteSync({bool recursive = false}) => _throw();
+
+  @override
+  bool existsSync() => _throw();
+
+  @override
+  Future<bool> exists() => _unsupported();
+
+  @override
+  bool get isAbsolute => true;
+
+  @override
+  RandomAccessFile openSync({FileMode mode = FileMode.read}) => _throw();
+
+  @override
+  Future<RandomAccessFile> open({FileMode mode = FileMode.read}) =>
+      _unsupported();
+
+  @override
+  Stream<List<int>> openRead([int? start, int? end]) =>
+      Stream<List<int>>.error(_unsupportedError());
+
+  @override
+  IOSink openWrite(
+          {FileMode mode = FileMode.write, Encoding encoding = utf8}) =>
+      _throw();
+
+  @override
+  Directory get parent => _throw();
+
+  @override
+  String get path => _throw();
+
+  @override
+  Future<int> length() => _unsupported();
+
+  @override
+  int lengthSync() => _throw();
+
+  @override
+  Future<Uint8List> readAsBytes() => _unsupported();
+
+  @override
+  Uint8List readAsBytesSync() => _throw();
+
+  @override
+  Future<String> readAsString({Encoding encoding = utf8}) => _unsupported();
+
+  @override
+  String readAsStringSync({Encoding encoding = utf8}) => _throw();
+
+  @override
+  Future<List<String>> readAsLines({Encoding encoding = utf8}) =>
+      _unsupported();
+
+  @override
+  List<String> readAsLinesSync({Encoding encoding = utf8}) => _throw();
+
+  @override
+  Future<File> rename(String newPath) => _unsupported();
+
+  @override
+  File renameSync(String newPath) => _throw();
+
+  @override
+  Future<String> resolveSymbolicLinks() => _unsupported();
+
+  @override
+  String resolveSymbolicLinksSync() => _throw();
+
+  @override
+  Future<DateTime> lastAccessed() => _unsupported();
+
+  @override
+  DateTime lastAccessedSync() => _throw();
+
+  @override
+  Future<DateTime> lastModified() => _unsupported();
+
+  @override
+  DateTime lastModifiedSync() => _throw();
+
+  @override
+  FileStat statSync() => _throw();
+
+  @override
+  Future<FileStat> stat() => _unsupported();
+
+  @override
+  Uri get uri => _throw();
+
+  @override
+  String get basename => _throw();
+
+  @override
+  String get dirname => _throw();
+
+  @override
+  Stream<FileSystemEvent> watch(
+          {int events = FileSystemEvent.all, bool recursive = false}) =>
+      Stream<FileSystemEvent>.error(_unsupportedError());
+
+  @override
+  Future<File> writeAsBytes(List<int> bytes,
+          {FileMode mode = FileMode.write, bool flush = false}) =>
+      _unsupported();
+
+  @override
+  void writeAsBytesSync(List<int> bytes,
+          {FileMode mode = FileMode.write, bool flush = false}) =>
+      _throw();
+
+  @override
+  Future<File> writeAsString(String contents,
+          {FileMode mode = FileMode.write,
+          Encoding encoding = utf8,
+          bool flush = false}) =>
+      _unsupported();
+
+  @override
+  void writeAsStringSync(String contents,
+          {FileMode mode = FileMode.write,
+          Encoding encoding = utf8,
+          bool flush = false}) =>
+      _throw();
+
+  @override
+  void setLastAccessedSync(DateTime time) => _throw();
+
+  @override
+  Future<File> setLastAccessed(DateTime time) => _unsupported();
+
+  @override
+  void setLastModifiedSync(DateTime time) => _throw();
+
+  @override
+  Future<File> setLastModified(DateTime time) => _unsupported();
+
+  T _throw<T>() => throw _unsupportedError();
+  Future<T> _unsupported<T>() => Future<T>.error(_unsupportedError());
+  UnsupportedError _unsupportedError() =>
+      UnsupportedError('IndexedDbFile is only available on web');
+
+  @override
+  FileSystem get fileSystem => _throw();
+}

flutter_cache_manager/lib/src/storage/file_system/indexed_db_file_system_stub.dart

@@ -0,0 +1,13 @@
+import 'package:file/file.dart' as file_pkg;
+import 'package:flutter_cache_manager/src/storage/file_system/file_system.dart'
+    as cache_fs;
+
+// Non-web stub to satisfy conditional export when js_interop is unavailable
+class IndexedDbFileSystem implements cache_fs.FileSystem {
+  IndexedDbFileSystem(String databaseName);
+
+  @override
+  Future<file_pkg.File> createFile(String name) async {
+    throw UnsupportedError('IndexedDbFileSystem is only available on web');
+  }
+}