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

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.

1 Answer

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.