5/7 Bleep Bleep Help?


I couldn't figure this out:

var cashRegister = {
    //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;


//Void the last transaction and then add 3 instead
//Show the total bill
console.log('Your bill is '+cashRegister.total);


I remember this one and having great difficulty with it. Anyway, on the instructions, it says...

> 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.

This means you have to create a new property called lastTransactionAmount. You already have the total property declared so declaring the lastTransactionAmount property will be similar to this one.

Then in the hint section it says the value of the lastTransactionAmount property will be changed to the item cost in the add method. Again, its already been done with the total property so putting in the lastTransactionAmount in the add function will be similar.


in your voidLastTransaction method,
you shall define the variable lastTransactionAmount (just like the total variable, set it to a initial value to 0)
in the add function, change the lastTransactionAmount to itemCost
when you call the function voidLastTransaction(lastTransactionAmount), the new total will subtract the lastTransactionAmount.


var cashRegister = {
lastTransactionAmount: 0,


Never mind I solved it