Lesson 5 Pl help Error says Oops try again false


#1

Here is my code

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

Small mistake, I thought you could catch it.
voidLastTransaction: function() {
this.total -= this.lastTransactionAmount;
}

The code you want is:

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

You dont need this.lastTransactionAmount, take out the this. and you should be fine.


#3

Don't forget to add lastTransactionAmount to the cashRegister.add method:

"We need to keep track of how much the last transaction was. Modify the add method to keep track of the amount of the last transaction. This should be tracked in a new property, lastTransactionAmount."

Add this code into cashRegister.add method

this.lastTransactionAmount = itemCost;

That should probably fix your error.