How is the setter method getting its argument?

Yes to both your questions. You're correct. In MDN docs it states "a setter can be used to execute a function whenever a specified property is attempted to be changed"

So the setter is called, because this book.out property is being set to 'true'

The parameter of the setter receives this new 'true' value from the book.out = true in the checkOut(book) method.

Ref: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/set

Hi Jonathan, In the class Book we have the property this._out = false;. In our setter out, the if statement checks to see if this._out is true or false;

If the setter is = true, then it will execute the block of code that calculates the due date. Then the getter out will return the value of the setter out. If setter out is = true then getter out will return the due date. If setter out is = false then getter out will return false

So when the checkOut method is executed for a patron the return value of the getter out of the Book class will determine if book.out = true in the checkOut method is true or false.

I hope that makes sense and hopefully, I have understood it correctly too.

Maybe someone else will be able to let us know if I'm right.

One thing I think I understand is that getters return values, a setter can perform logic on a value or update an existing property with that value. So the setter does all the hard work and the getter stores that hard work or rather returns the value of the setter.

Didn't click, but this was the best explanation found on the web , Source: [https://discuss.codecademy.com/t/why-dont-we-need-parenthesis-for-getters/435463/2]

"get attribute () { return this._attribute; } *We write a get call the way we would access an object property, normally.

console.log(object.attribute); We know there is no literal attribute by that name, but a backing variable with an underscore, which value is returned by the getter. We never invoke the getter method as we would a typical method, since it is self-invoking and accesses the actual attribute and returns it.

Likewise, we never invoke a setter, but call it like we would be making an assignment.

object.attribute = newValue; The mechanics behind the scene are such that we cannot access (get) a variable while it is being set. It’s a bit complicated to fully understand, let alone explain, but warrants further study as you get more immersed in the finer details. Add this to your reading list."*