JSFiddle - React, Tailwind, and code Playground

HTML

<div id="dates">
</div>

JavaScript

function recurringDates(startDate, endDate, interval) {
    var date = startDate;
    var dates = [];

    while ((date = addDays(date, interval)) < endDate) {
        dates.push(date);
    }

    return dates;
}

function addDays(date, days) {
    var newDate = new Date(date);
    newDate.setDate(date.getDate() + days);
    return newDate;
}

var startDate = new Date(2015, 0, 1);
var endDate = new Date(2016, 0, 1);
var interval = 20;
var dates = recurringDates(startDate, endDate, interval);
var datesElement = $("#dates");
dates.forEach(function(date) {
    datesElement.append("<div>" + date + "</div>");
});