Bleep Bleep, code not working correctly?

#1

https://www.codecademy.com/courses/close-the-super-makert/0/5?curriculum_id=506324b3a7dffd00020bf661#

It says SyntaxError: Unexpected Token

//Dont forget to add your property
    add: function(itemCost) {
        this.total +=  itemCost;
        this.lastTransactionAmount = itemCost;
    },
    scan: function(item,quantity) {
        switch (item) {
        case "eggs": this.add(0.98 * quantity); break;
        case "milk": this.add(1.23 * quantity); break;
        case "magazine": this.add(4.99 * quantity); break;
        case "chocolate": this.add(0.45 * quantity); break;
        }
        return true;
    },
    //Add the voidLastTransaction Method here
    voidLastTransaction: function() {
        this.total -= this.lastTransactionAmount;
    };
};

cashRegister.scan('eggs',1);
cashRegister.scan('milk',1);
cashRegister.scan('magazine',1);
cashRegister.scan('chocolate',4);

//Void the last transaction and then add 3 instead
cashRegister.voidLastTransaction()
cashRegister.scan('chocolate',3);

//Show the total bill
console.log('Your bill is '+cashRegister.total);
#2

I understand what I did wrong, but why is ; at the }; considered wrong?

#3

In the following code:

var cashRegister = {
//Dont forget to add your property
    add: function(itemCost) {
        this.total +=  itemCost;
        this.lastTransactionAmount = itemCost;
    },
    scan: function(item,quantity) {
        switch (item) {
        case "eggs": this.add(0.98 * quantity); break;
        case "milk": this.add(1.23 * quantity); break;
        case "magazine": this.add(4.99 * quantity); break;
        case "chocolate": this.add(0.45 * quantity); break;
        }
        return true;
    },
    //Add the voidLastTransaction Method here
    voidLastTransaction: function() {
        this.total -= this.lastTransactionAmount;
    }; // line (A)
};

You are asking why, on line A, }; is considered incorrect. The reason is because cashRegister is an object. When defined using the object literal syntax, it should have the following structure:

var cashRegister = {
    prop1: val1,
    prop2: val2,
    prop3: val3
};

Notice that a comma is used to separate properties and the last property needs no comma separator.

Now, in your code, there’s a ; after the last property definition. That’s why you are getting an error.