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JavaScript Practice Object Interaction Checking Out and Returning a Book Solution: Charging Fines to Patrons

Posted by Dan Ingenthron
Dan Ingenthron
8,769 Points

Is the code meant to charge the same fine for each day the book is late?

By adding a multiplier for 'days late', this seems to be set up to charge $.10 the first day, $.20 the 2nd day, $.30 the 3rd day, and so on. By 'daily fine' I understood the code to be a little simpler, like this:

chargeFines() {
    const now = new Date();

    const latePatrons = this.patrons.filter(patron => 
        (patron.currentBook !== null && patron.currentBook.dueDate < now)
    );

    for (let patron of latePatrons) {
        patron.balance += this.dailyFine;
    }
}

This adds a $.10 daily fine to the patron's balance until the book is returned. This is a small detail, but just including in case anyone else read the problem this way.

2 Answers

Brian Crowe
seal-mask
.a{fill-rule:evenodd;}techdegree
Brian Crowe
Full Stack JavaScript Techdegree Student 5,975 Points
Brian Crowe
.a{fill-rule:evenodd;}techdegree
Brian Crowe
Full Stack JavaScript Techdegree Student 5,975 Points

I got there on my own, reassigning patron.balance to a calculated fine. Then I saw the solution and thought I had this all messed up. Came here to check and realized that at least some other people found the compounding fine ridiculous. Thank you.

KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,972 Points
KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,972 Points

The instructions specify:

dailyFine ... charged to each Patron for every day their checked out book is overdue

So there is a fine for each day which is why the multiplier is used.

Jeremy Yochum
.a{fill-rule:evenodd;}techdegree seal-36
Jeremy Yochum
Front End Web Development Techdegree Graduate 16,023 Points

If you use the multiplier by having patron.balance += this.dailyFine * daysLate; then after a year you would have to pay $6,679.50 for that book. Just take the plus sign off to reassign the property with the new value.