Update

lib/api/api_result.dart

@@ -0,0 +1,22 @@
+import 'package:json_annotation/json_annotation.dart';
+
+part 'api_result.g.dart';
+
+@JsonSerializable(genericArgumentFactories: true)
+class ApiResult<T> {
+  const ApiResult({
+    required this.ok,
+    required this.status,
+    this.data,
+    this.error,
+  });
+  factory ApiResult.fromJson(
+          Map<String, dynamic> json, T Function(Object?) fromJsonT) =>
+      _$ApiResultFromJson(json, fromJsonT);
+  final bool ok;
+  final int status;
+  final T? data;
+  final String? error;
+  Map<String, dynamic> toJson(Object? Function(T) toJsonT) =>
+      _$ApiResultToJson(this, toJsonT);
+}