7. You Deserved It! - wrong discount?


#1

I'm supposed to get 20% discount, but even when I have everything right (as far as I can tell), it still says "Oops, try again. Your discountPercent should be 20!". Code below:

function StaffMember(name,discountPercent){
    this.name = name;
    this.discountPercent = discountPercent;
}

var sally = new StaffMember("Sally",5);
var bob = new StaffMember("Bob",10);

// Create yourself again as 'me' with a staff discount of 20%
var me = new StaffMember("Tom", 20);

var cashRegister = {
    total:0,
    lastTransactionAmount: 0,
    add: function(itemCost){
        this.total += (itemCost || 0);
        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;
    },
    voidLastTransaction : function(){
        this.total -= this.lastTransactionAmount;
        this.lastTransactionAmount = 0;
    },
    // Create a new method applyStaffDiscount here
    applyStaffDiscount: function(employee) {
        this.total -= this.total * (employee.discountPercent /= 100);
    }
};

cashRegister.scan('eggs',1);
cashRegister.scan('milk',1);
cashRegister.scan('magazine',3);
// Apply your staff discount by passing the 'me' object 
// to applyStaffDiscount
cashRegister.applyStaffDiscount(me);

// Show the total bill
console.log('Your bill is '+cashRegister.total.toFixed(2));


#2

The above does not look quite right.

Consider this simple algebra...

let y = this.total
let x = employee.discountPercent

y = y - y * x / 100   // factor out y on the right side

y = y * (1 - x / 100)

// Rewriting as a JS augmentation assignment...

y *= 1 - x / 100

So,

this.total *= 1 - employee.discountPercent / 100

#3

Oh yeah, I didn't notice the "=/"... I think I just copied all of it from previous attempt. So I deleted the "=" and not it works fine. Thanks.


#4

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