Initial draft

lib/persistence.dart

@@ -0,0 +1,20 @@
+import 'package:path_provider/path_provider.dart';
+import 'dart:io';
+
+class FileStorage {
+  Future<String> _path(String file) async {
+    return "${(await getApplicationDocumentsDirectory()).path}/$file";
+  }
+
+  Future<void> write(String name, String content) async {
+    await File(await _path(name)).writeAsString(content);
+  }
+
+  Future<String> read(String name) async {
+    return await File(await _path(name)).readAsString();
+  }
+
+  Future<bool> exist(String name) async {
+    return File(await _path(name)).exists();
+  }
+}