JS Time calculation

 calculate(endTime) {
    let startTime = this.getStartTime();
    while (startTime <= endTime) {
      this.availableTimes.push(moment(startTime));
      startTime.add('m', 45);
    }
    return this.availableTimes;
  }


  getStartTime() {
    let selectedDate = this.navigatOBJ.date.toLocaleDateString('en-US');
    let now = new Date().toLocaleDateString('en-US');
    if (moment(selectedDate).isAfter(now)) {
      return moment().hour(8).minute(30)
    } else {
      return moment().add('m', 45 - moment().minute() % 45)
    }
  }
---
$(function(){
    var dtToday = new Date();
   
    var month = dtToday.getMonth() + 1;
    var day = dtToday.getDate();
    var year = dtToday.getFullYear();
    if(month < 10)
        month = '0' + month.toString();
    if(day < 10)
        day = '0' + day.toString();
   
    var maxDate = year + '-' + month + '-' + day;
    alert(maxDate);
    $('#txtDate').attr('min', maxDate);
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="date" id="txtDate" />