class Customer { final String id; final String firstName; final String lastName; final String phoneNumber; Customer({ required this.id, required this.firstName, required this.lastName, required this.phoneNumber, }); String get fullName => '$firstName $lastName'.trim(); Map toMap() { return { 'id': id, 'firstName': firstName, 'lastName': lastName, 'phoneNumber': phoneNumber, }; } factory Customer.fromMap(Map map) { return Customer( id: map['id'], firstName: map['firstName'], lastName: map['lastName'], phoneNumber: map['phoneNumber'], ); } }