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JavaScript Object-Oriented JavaScript (2015) Prototypal Inheritance Setting Up the Prototype Chain

Posted by Mateusz Hyla
Mateusz Hyla
11,210 Points

What is wring with my code [OOP JavaScript]?

Hello

I have a problem with code challange. There is said to call a constructor of Person class in Teacher constructor. I done that like :

Person.call(this , firstName , lastName);

And it shows me an error that firstName and lastName does not need to be set up there.

When I try another approach like :

Person.call("Matt","Hyla");

It said that I need to place arguments in order like : "this" , "firstName" and "lastName",

I don't know what to do now. What am I doing wrong ?

Cheers

person.js 
function Person(firstName, lastName) {
  this.firstName = firstName;
  this.lastName = lastName;
}

Person.prototype.fullName = function() {
 return this.firstName + " " + this.lastName; 
};
teacher.js 
function Teacher(firstName, lastName, roomNumber) {
  this.firstName = firstName;
  this.lastName = lastName;
  this.room = roomNumber;
}

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

:point_right: You had the right idea the first time.

You probably just forgot to remove the redundant lines from the Teacher constructor:

teacher.js 
function Teacher(firstName, lastName, roomNumber) {
  Person.call(this, firstName, lastName); // this sets up both names, we don't need to here
  this.room = roomNumber;                 // but we still assign the room
}