closure return function doesn't changes scoped variable

Question

function testLet(){
    var x=9;
    return{
        y:x,
        getX: function(){
            return ++x;
        },
    }
}

var obj = new testLet();
console.log(obj.y); //9 as expected
console.log(obj.getX()); //10 as expected
console.log(obj.getX()); //11 as expected
console.log(obj.y); //I expect it 11.. but it stays 9

Why the last line returns 9 instead of 11 as x is in the same scope?

Answer 1

y:x means "Copy the current value of x to the property y ".

The value, at the time, is 9 .

Subsequent changes to the value of x won't change the value of y .

---

You can either change your getX function to modify this.y , or you can change the y property to be a getter function which reads the current value of x .