text: ({
  	init: function (cmp, evt, helper) {
  		var listSize = cmp.get("v.initialSize");
  		cmp._virtualItems = [];
  		
  		helper.generateListItems(0, listSize, function(item) {
  			cmp._virtualItems.push(item);
  		});
      },
      
      onLoadMore: function(cmp, callback, helper) {
      	var currentSize = cmp._virtualItems.length;
      	var tempList = document.createDocumentFragment();
      	
      	setTimeout(function() {
      		helper.generateListItems(currentSize, currentSize + 20, function(item, index) {
  	    		cmp._virtualItems.push(item);
  	    		tempList.appendChild(item);
  	    		
  	    		if (index == currentSize + 19) {
  	    			cmp.find("body").getElement().appendChild(tempList);
  	    			callback();
  	    		}
      		})
      	}, cmp.get('v.loadDelay_ms'));
      }
  })