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

Posted by Adiv Abramson
Adiv Abramson
6,919 Points

Why doesn't Person.call(this, firstName, lastName); work?

I get an error message that the Person object will set the first and last name properties. I have no idea what the editor is on about. I mimicked the call used in the video tutorial on inheritance:

    Media.call(this, title, duration);
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;

  Person.call(this, firstName, lastName);
}//Teacher

1 Answer

Sara Hardy
Sara Hardy
8,650 Points
Sara Hardy
Sara Hardy
8,650 Points

You don't need to call this.firstName = firstName; and this.lastName = lastName; inside Teacher because those will be set inside Person. You can remove those lines. You will still need to set this.room = roomNumber; because that is specific to just a Teacher.

Adiv Abramson
Adiv Abramson
6,919 Points

Thank you! It makes perfect sense now. :-)

MUZ140884 Maxwell Makumucha
MUZ140884 Maxwell Makumucha
6,291 Points

hie, was following a discussion you did on a particular area under this topic. How do it to get through because i cant get the right object to call. Pliz help