[рони]

и 30

<script>
 let dateFormat = d => d.toLocaleDateString("ru");
function getDates(date)
           {  var arr = [];
              date = new Date(date);
              if(!date) return arr;
              var days = 7;
              date.setDate(date.getDate()  + days);
              var month = date.getMonth();
              while (date.getMonth() == month) {
                  arr.push(dateFormat(date))
                  date.setDate(date.getDate()  + days);
              }
              return arr;
           }
document.write(getDates(new Date(2020, 2, 3).getTime()))
  </script>