Help: chargeFines() What would happen if this method was called more than once while a patron had the same book overdue?

Hi Steven Parker, thanks so much taking the time to answer. I just noticed the spelling myself and yes, it looks weird :) I will edit that and make it to something else. You might have glanced over it but I do have my workspace screenshot at the beginning of my previous message. I will paste it again here Here is snapshot of my TreeHouse Workspace https://w.trhou.se/jrx29d56bc

Ah! So I was under the impression that the first time the loop in the code runs, it will add "Johnny Bravo" name property into the empty lateChargedPatron array and then the second time I invoke the chargeFines() method, it should see that "Johnny Bravo" is already in the lateChargedPatron array and print Don't Charge to the console.

Are you saying that each time I will invoke the chargeFines() method the lateChargedPatron will be given an empty array and whatever was in it from before gets overwritten? Will this have to be done by some sort of database where its keeping track of all the Patrons that were charged late fees.

Yes, you are correct, this exercise was limited to checking out only one book. I love the "lateBooks" idea and will try to implement that next.

My goal with this one was to keep track of the Patrons who were already charged a late fee and lets say I invoke the chargeFines() method on the same day, that particular Patron should not get charged again.

The future goal is to add a logic where I invoke the method a day later and it adds 10c to the current balance. I am guessing that I will have to create a new Date() object which will keep track of when the Patron was last charged. The difference of the current date and the last charged date will give me the number of additional days the fees needs to be charged.

So first time around the balance for Johnny Bravo is 1.40000... If I invoke the chargeFines() method again it should output "Dont charge" and maintain the 1.40000... balance.

Right now it adds "Johnny Bravo" every iteration and the balance keeps getting doubled.

Hope this explanation helps.

Again, I really appreciate your help.

    chargeFines() {
        const today = new Date();
        const latePatrons = this.patrons.filter(patron => patron.currentBook !== null && patron.currentBook.dueDate < today);

        // Challenge: run chargeFines() method without doubling the fine for the patron
        const lateChargedPatron = [];

        for (const latePatron of latePatrons) {
            // If patron is already charged, charge him only for the difference of days since last check
            if (lateChargedPatron.includes(latePatron.name)) {
                console.log("Dont Charge")
            } else {
                const daysLate = today.getDate() - latePatron.currentBook.dueDate.getDate();
                latePatron.balance += (daysLate * this.dailyFine);
                lateChargedPatron.push(latePatron.name);              
            }

            console.log(lateChargedPatron);
        }

Thanks for the pointers Steven Parker. That's a great approach and I can also use the same to remove Patrons who have paid the balance.

I was able to find a solution to my "keeping track of the overdue Patrons" by adding an overdue array to the Library object. Now it doesn't print "Johnny Bravo" if I invoke the chargeFines() method multiple times. Now I will use the Date approach you mentioned and that should make it much simpler.

class Library {
    constructor(books, patrons, dailyFine, overdue) {
        this.books = [];
        this.patrons = [];
        this.dailyFine = 0.1;
        this.overdue = []; // Store Patrons who have overdue books
    }

Now when I invoke the chargeFines() method the second of third time, it knows Patron.name exists in the overdue array. It was a simple thing but I took me a while to make that connection

    chargeFines() {
        const today = new Date();
        const latePatrons = this.patrons.filter(patron => patron.currentBook !== null && patron.currentBook.dueDate < today);

        for (const latePatron of latePatrons) {
            if (this.overdue.includes(latePatron.name)) {
                console.log("Dont Charge")
            } else {
                const daysLate = today.getDate() - latePatron.currentBook.dueDate.getDate();
                latePatron.balance += (daysLate * this.dailyFine);
                this.overdue.push(latePatron.name);              
            }
        }

Thanks again for all your time and help. I really appreciate it. This was a very good exercise by TreeHouse and I hope to see a lot more like these. Hopefully this will be helpful for someone else.

Doesn't this only work if "today" and the "due date" fall on the same month?? wouldn't it be better to use some sort of a function that gets executed automatically, say every 24 hours and adds the daily fine to the balance of the over due patrons.