angularjs - JavaScript sorting on date (but not the "usual" way) -

i'm trying sort js array, in different fashion. here's scenario:

say have following dates in array (these each item's expirydate)

1. 2015/09/23 2. 2015/10/10 3. 2015/07/05 4. 2015/07/24 

and current date 2015/07/04 , select 2015/09 (which vm.sortmodel in example) sorting date display order must follows -

3.  1.  4.  2.  

here's have far, it's not working...

for (var = 0; < vm.tabledata.length; i++) {     var entity = vm.tabledata[i];     entity.items.sort(function(a, b) {         if (a.expiresthisweek() < b.expiresthisweek()) {             return 1;         }          //now check stuff in months after selected year/month combo         if (vm.sortmodel) {             var tmp = vm.sortmodel.split('/');             var currentdateselection = new date(tmp[0], tmp[1]);              if (a.getexpirydateobject() >= currentdateselection) {                 return 1;             } else {                 return -1;             }         }          if (a.getexpirydateobject() < b.getexpirydateobject()) {             return -1;         } else if (a.getexpirydateobject() > b.getexpirydateobject()) {             return 1;         }          return 0;     }); } 

basically, if item expires in week, must @ top of table, should list items in "selected month", months after month, , then months before that.

very strange, know, business gets business wants.

thanks help!

edit

here's expiresthisweek method

model.expiresthisweek = function() {     var todaydate = new date();     //we want check if item expires within 7 days today     var enddate = new date(todaydate.getfullyear(), todaydate.getmonth(), todaydate.getdate() + 7);     var date = model.getexpirydateobject();      return todaydate < date && date < enddate; }