JSFiddle - React, Tailwind, and code Playground

HTML

<div class="demo"></div>

JavaScript

var dateStart="31-08-2018";
    var splitSrt = dateStart.split("-");
  	var dateSrt = new Date(splitSrt[2], splitSrt[1] - 1, splitSrt[0]);
    var currentDay = dateSrt.getDate();
    var nBill=10;
    var mthBill=6;
    
  for (var i=1 ; i<=nBill ; i++ ){
  		var currentMonth = dateSrt.getMonth();
  		if(i===1){
          currentMonth=currentMonth;
      }else if(i===2){
      		currentMonth=currentMonth+(mthBill-1);
      }else if(i<=nBill){
      		currentMonth=currentMonth+(mthBill);
      }
      dateSrt.setMonth(currentMonth, currentDay);
      if (dateSrt.getMonth() > currentMonth + 1) 	dateSrt.setDate(0);
      srvDay= $.datepicker.formatDate('dd-mm-yy', dateSrt);
      $(".demo").append("<label>"+srvDay+"</label><br>");
      
      if(i===2){
          dateSrt.setMonth(currentMonth+1, currentDay);
          if (dateSrt.getMonth() > currentMonth + 1) 	dateSrt.setDate(0);
      }
      
  }