Generate calendar of monthly credit fees in JavaScript

Question

I have small credit calculator and I neeed to add monthly fees dates to the calendar (table).

For example, I have first fee date 10.11.2016 and 12 payments. Table should be like this:

# | date | fee 1 | 10.11.2016 | 500$ 2 | 10.12.2016 | 500$ 3 | 10.01.2017 | 500$ 4 | 10.02.2017 | 500$ ... 12 | 10.10.2017 | 11$

How to do this?

Answer 1

Date.isLeapYear = function (year) {
    return (((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0));
};

Date.getDaysInMonth = function (year, month) {
    return [31, (Date.isLeapYear(year) ? 29 : 28), 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][month];
};

Date.prototype.isLeapYear = function () { 
    return Date.isLeapYear(this.getFullYear()); 
};

Date.prototype.getDaysInMonth = function () { 
    return Date.getDaysInMonth(this.getFullYear(), this.getMonth());
};

Date.prototype.addMonths = function (value) {
    var n = this.getDate();
    this.setDate(1);
    this.setMonth(this.getMonth() + value);
    this.setDate(Math.min(n, this.getDaysInMonth()));
    return this;
};