5/7 Not a function error


#1

I am getting the error "cashRegister.voidLastTransaction" is not a function. Does anyone see what I'm doing wrong?

var cashRegister = {
    total:0,
    lastTransactionAmount: 0,
    //Dont forget to add your property
    add: function(itemCost) {
        this.total +=  itemCost;
        this.voidLastTransaction = 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.voidLastTransaction;
    }
    
};

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);

Thanks!


#2

in these blocks

    add: function(itemCost) {
        this.total +=  itemCost;
        this.voidLastTransaction = itemCost;
    },

//and

    voidLastTransaction: function() {
        this.total -= this.voidLastTransaction;
    }

instead of this.voidLastTransaction you should rather be using this.lastTransactionAmount;


#3

Great! It works now. Thanks for your help!