GETTER SETTER question

JavaScript
1

In the course video 12 there is this file explaning all.


function Circle(radius) {
    this.radius= radius;

    let defaultLocation = {x : 0 ,y : 0 };

    this.defaultLocation= function(){
        return defaultLocation;
    };

    this.draw = function () {
        console.log('draw');   
    };

    Object.defineProperty(this , 'defaultLocation', {
        get : function (){
            return defaultLocation;
        },
        set : function ( value ) {
            if (!value.x || ! value.y)
                throw new Error('invalid Location!! CIAO');
            defaultLocation = value;
        }
    });
}

const circle = new Circle(10);
//circle.defaultLocation = 1;
circle.draw();

I recap what i understand:
Get → read
Set → Write

Where can i found a part when i call this methods from outside?
i means …

When there is this object.defineProperties ( #1,#2,#3);

Legend :
with #1 i refer to parameter number 1
with #2 i refer to parameter number 2
with #3 i refer to parameter number 3

  1. #1, i will pass “this” keyword ( i undestand this ok! )
  2. #2 i will pass a function but where this funcion it’s called ? ( i don’t undestand this )
  3. #3. We pass an object for todo something like check variable with set/get ( ok undestand half …because here i found an return defaullocation )

when video start mosh say we want to use like

//circle.defaultLocation = 1;

i comment this line because if i do doesn works