class UserModel { String username; DateTime createdAt; DateTime updatedAt; String userId; UserModel({ required this.username, required this.createdAt, required this.updatedAt, required this.userId, }); factory UserModel.fromJson(Map<String, dynamic> json) { return UserModel( username: json['username'], createdAt: DateTime.parse(json['createdAt']), updatedAt: DateTime.parse(json['updatedAt']), userId: json['userId'], ); } Map<String, dynamic> toJson() { return { 'username': username, 'createdAt': createdAt.toIso8601String(), 'updatedAt': updatedAt.toIso8601String(), 'userId': userId, }; } }