class User { final String id; final String email; final String? firstName; final String? lastName; User({ required this.id, required this.email, this.firstName, this.lastName, }); factory User.fromJson(Map json) { return User( id: json['id'].toString(), email: json['email'] as String, firstName: json['first_name'] as String?, lastName: json['last_name'] as String?, ); } String get displayName { if (firstName != null && lastName != null) { return '$firstName $lastName'; } if (firstName != null) { return firstName!; } return email; } }