Bleep Bleep lastTransactionAmount Error


#1



Hi guys, i'm stuck in this code and i can't get why i'm getting this error:
ReferenceError: lastTransactionAmount is not defined

Here is my code:


var cashRegister = {
total:0,
lastTransactionAmount : 0,
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 -= 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)

I defined "lastTransactionAmount " in line 3, so why am i getting this error?
Thanks guys!


#2

hi, you have to use "this."

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


#3

Thanks netsolver! I can't believe i forgot this hahaha