Setup <select>

by supercool

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.3.0/knockout-min.js"></script>
<div data-bind="foreach:main">
<ul data-bind="foreach:$parent.filter($data)">
    <li data-bind="text:'gotcha'+$data"></li>
</ul>
</div>

JavaScript

var viewModel = function(){
  var self=this;
  self.main=ko.observableArray([1,2,4]);  
   self.filter = function(data){
   if(data==1){return [1,1,1]}
   if(data==4){return [4,4,4]}
   if(data==2){return [2,2,2]}
    }
}
ko.applyBindings(new viewModel())