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Start your free trialSamuel Kleos
Front End Web Development Techdegree Student 13,307 PointsConfusion. . . 😵💫 Why is my daysOverDue property negative?
In my Library class I used filter and reduce to generate a .daysOverDue value from a book using a getter method in the book class. Also, a setter method out() is used to set .dueDate to -14 days (in the past):
chargeFines() {
const now = new Date();
const latePatrons = this.patrons.filter(patron =>
(patron.currentBook !== null && patron.currentBook.dueDate < now)
);
for (let patron of latePatrons) {
const daysLate = Math.floor( (now.getTime() - patron.currentBook.dueDate.getTime()) / (1000 * 60 * 60 * 24));
patron.balance += this.dailyFine * daysLate;
}
}
My solution:
collectFines() {
let today = new Date();
console.log(today.getDate())
return this.patrons
.filter(patron => (patron.currentBook.daysOverDue > 0))
.reduce((collector, patron) => {
console.log(patron.currentBook.dueDate.getDate());
patron.balance = -patron.currentBook.daysOverDue * this.dailyFine;
return collector + -patron.balance;
}, 0);
}
Here is my Book class where dueDate is set and daysOverDue is calculated:
set out(value) {
this._out = value;
if (value) {
let today = new Date();
today.setDate(today.getDate() - 14);
this.dueDate = today;
} else {
this.dueDate = null;
}
}
get daysOverDue() {
let today = new Date();
let daysOverDue = today.getDate() - this.dueDate.getDate();
return daysOverDue
}
ASIDE: What's the difference between
this.dueDate = today.setDate(today.getDate() - 14);
and
today.setDate(today.getDate() - 14);
this.dueDate = today;
1 Answer
Travis Alstrand
Treehouse TeacherI found this page which shows an example of using getDate
and setDate
about halfway down and subtracting days from them. I'm not exactly sure why you're getting a negative number back, if the date it has is less than 14 would it go negative and not loop through the end of the previous month?
I hope this is helpful, if not please let me know!
Travis Alstrand
Treehouse TeacherTravis Alstrand
Treehouse TeacherIf you have a GitHub repo that you can share the link to, it'd be easier to play with it and see if we can come up with a solution. But I'm unfortunately not 100% sure why it's doing that to you, my apologies.