Question

In the following function, with a method inside of it called newlastname :

function person(firstname,lastname,age,eyecolor)
{
  this.firstname=firstname;
  this.lastname=lastname;
  this.age=age;
  this.eyecolor=eyecolor;

  this.newlastname=newlastname;
}


function newlastname(new_lastname)
{
  this.lastname=new_lastname;
}

In the line this.newlastname=newlastname; what is happening? What does the first newlastname refer to? I appreciate any tips or advice.

Answer 1

In this line of code:

this.newlastname=newlastname;

The first newlastname is a property on the person object.

The second newlastname is a reference to the newlastname() function.

So, when you do this:

this.newlastname=newlastname;   

you are storing a reference to that function in a property of the person object. That would allow the following code to work:

var p = new person("Ted", "Smith", 31, "blonde");
p.newlastname("Bundy");

When you execute p.newlastname("Bundy");, it will look for a property on the person object called newlastname. When it finds that property, it will execute that function and pass it "Bundy" and set this to be the particular person object.