Set jQuery Range Slider Max value as Current Month using JavaScript

I want to display the current month automatically when the month goes from one month to next month in the maximum range slider in jquery ui

Note: Current date is always 01

 //range slider in months
    function formatDate(date) {
        debugger;
        var monthNames = [
            "January", "February", "March",
            "April", "May", "June", "July",
            "August", "September", "October",
            "November", "December"
        ];
        var monthIndex = date.getMonth();
        var year = date.getFullYear();
        return monthNames[monthIndex] + ' ' + year;
    }
    function formatDateTime(dateTime) {
        var date = "01";
        var month = ("00" + (dateTime.getMonth() + 1)).slice(-2);
        var year = dateTime.getFullYear();
        var hour = ("00" + dateTime.getHours()).slice(-2);
        var minutes = ("00" + dateTime.getMinutes()).slice(-2);
        var seconds = ("00" + dateTime.getSeconds()).slice(-2);
        return date + "-" + month + "-" + year + " " + hour + ":" + minutes + ":" + seconds;
    }
    $(function () {        
        $("#slider-range").slider({
            range: true,
            min: new Date('2019-01-01').getTime() + 86400000,
            max: new Date('2019-12-01').getTime() + 86400000,
            step: 86400000,
            values: [new Date('2019-04-01').getTime(), new Date('2019-11-01').getTime()],
            slide: function (event, ui) {
                $("#amount").val(formatDate(new Date(ui.values[0])) + '-' + formatDate(new Date(ui.values[1])));
            },
            stop: function (event, ui) {
                debugger;
                var start = formatDateTime(new Date(ui.values[0]));
                var end = formatDateTime(new Date(ui.values[1]));
                $('#lblStartDateTime').html(start);
                $('#lblEndDateTime').html(end);
                //$("#amount").val(formatDate(new Date(ui.values[0])) + '-' + formatDate(new Date(ui.values[1])));
                $.ajax({
                    data: { MinValue: start, MaxValue: end },
                    type: "post",
                    url: apiUrl + "/api/Warehouse/addMinMaxValues",
                    success: function (data) {
                        //alert("Data Save: " + data);
                    }
                });
            }
        });
        $("#amount").val(formatDate((new Date($("#slider-range").slider("values", 0)))) +
          " - " + formatDate((new Date($("#slider-range").slider("values", 1)))));
    });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
<link rel="stylesheet" href="https://code.jquery.com/resources/demos/style.css">
<script type="text/javascript" src="https://code.jquery.com/jquery-1.12.4.js"></script>
<script type="text/javascript" src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<input type="text" id="amount" readonly style="border:0; color:#f6931f; font-weight:bold; width:100%">                            
<div id="slider-range"></div>