16 Building a Cash Register


#1

var cashRegister = {
total:0,
//Dont forget to add your property
add: function(itemCost) {
this.total += itemCost;
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() {
cashRegister.total -= lastTransactionAmount;
//takes away the value of the last transaction form the current list of transactions
}

};

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();
//why not just voidLastTransaction();
cashRegister.scan("chocolate", 3);

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

okay so the code above runs just perfectly, however I'm just not quite understanding why we can use "lastTransactionAmount" which has been created inside a different function from the one of which it is called in "voidLastTransaction"


#2

voidLastTransaction method belongs to cashRegister object, that's why you cannot call it directly.


Regarding lastTransactionAmount - you actually forgot to declare this property. It belongs right after total.


#3

do you mean declare it outside of the add function?


#4

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.