I'm not sure if this will be useful, but here is the code I came up with:
RECORDS

Method
getTowerLeaveData_LV: function(monthyear, numOfDays,tower, userid, username) {
        var selectedMonthYear = monthyear.split("-");
        var tempArr = new Array();
        var reArr = new Array()
        tempArr.push(username)
        reArr.push(username);
        LeavesCollection.find({associate_tower: {$in: tower}, leaves_approval_status: {$ne: 'Rejected'}, user_id: userid},{sort:{leaves_timestamp   :-1}},{fields: {_id:1,user_id:1,associate_id:1, associate_fullname:1,leaves_type:1,leaves_start:1,leaves_end:1, leaves_days:1}}).forEach(
          function(leaver) {
              for(var a=1; a!=numOfDays+1; a++) {
                var dateActive = selectedMonthYear[0] + "/" + a.toString() + "/" + selectedMonthYear[1];
                var res = dateCheck(leaver.leaves_start, leaver.leaves_end,dateActive);
                if(res == true) {
                    tempArr.splice(a, 0,[leaver.leaves_approval_status,leaver.leaves_type,leaver._id,leaver.associate_fullname,a]);
                }
              }
          });
        for(var a=1; a!=numOfDays+1; a++) {
          var temp = findKey(tempArr,a);
          if(temp != false) {
            reArr.push(tempArr[temp]);
          } else {
            reArr.push('null')
          }
        }
        return reArr;
    },
FUNCTIONS MISC JS:
function dateCheck(from,to,check) {
    var fDate,lDate,cDate;
    fDate = Date.parse(from);
    lDate = Date.parse(to);
    cDate = Date.parse(check);
    if((cDate <= lDate && cDate >= fDate)) {
        return true;
    }
    return false;
}
function findKey(array, search) {
  var theIndex = false;
  for (var i = 0; i < array.length; i++) {
    if (array[i].indexOf(search) > -1) {
        theIndex = i;
        break;
    }
  }
  return(theIndex);
}
OUTPUT IN ARRAY:

EXPLANATION OF EXIT:
Elements after the name in the array are equal to numOfDays (these are dates). If the program finds a match date in the range between "leaves_start" and "leaves_end", it will return the array data from mongodb, if not, it will return "null".