You Deserved It!


#1


https://www.codecademy.com/courses/close-the-super-makert/0/7?curriculum_id=506324b3a7dffd00020bf661


No error message. Could someone explain the following below lines of code to me?
(1) this.total += (itemCost || 0); --- What purpose does the '||' serve?
(2) the parameter 'employee' is not introduced anywhere until the 'applyStaffDiscount' method. How does the code know to apply the StaffMember to the 'employee' parameter?
(3) console.log('Your bill is '+cashRegister.total.toFixed(2)); --- What purpose does the '.toFixed(2)' serve?

Thank you!


Replace this line with your code. 
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 ("me", 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

If itemCost is not a valid number, this expression returns 0 so that the total is not changed and no NaN results.


#3

employee is only a local parameter, determined by the argument in the call to the method.

applyStaffDiscount(me)

me in this case is defined as a StaffMember instance. That becomes the employee in the method.


#4

This number method reduces the number decimal places in the result, based on the 5/4 rounding rule. Technically, if the amounts in the instructions are followed, it is not needed. When the values are altered, it does come into play.


#5

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