I have done some tasks for my job, I have done all of them. But I have some problems, it doesn't work as it supposed to. When I'm trying to add a new user for Customer class, for example:

```
var user3 = new Customer ("Sergiu", "Tataru");

```

And when I access user3, I receive:

```
lastname: undefined

```

Why so?

See the result to understand what I mean

![result](https://i.stack.imgur.com/3ibMN.png)

The tasks that I have done:

1. Use a Person class and extend it for the Employee and Customer
classes.
2. The Person object has a private name property and a getter method for the name.
3. The Employee class has two private properties hire date and salary. It also has getter methods for the two properties.
4. The Customer class has a private contract number property and a getter for the contract number.

The code:

```js
//4)Create a Person class
class Person{
  constructor(firstName, lastName) {
    this.firstname = firstName;
    this.lastname = lastName;
    var _name = name;// create a private name property for the Person class

  // create a getter method for the name for the Person class
    this.getName = function () {
      return _name;
    };

    this.getFullName = function() {
      return this.firstname+ " " + this.lastname;
    };
  }
}

// extend Person class for the Employee and Customer classes.
class Employee extends Person {
  constructor(hireDate, salary){

  super(hireDate, salary);
  var _hiredate = hireDate; // create a private property hire date for  Employee class
  var _salary = salary; // create a private property salary for  Employee class

  // create a getter method for the hire date s
  this.getHireDate = function(){
  return _hiredate;
};
  // create a getter method for the salary
  this.getSalary = function(){  //varianta alternativa:  Employee.prototype.getSalary = function(){
  return _salary;
};
}
}

class Customer extends Person {
constructor(contractNumber){

super(contractNumber);
var _contractNumber = contractNumber; // create a private contract number for Customer class

//create a  getter for the contract number.
this.getcontractNumber = function(){
return _contractNumber;
};
};
}
```