I have a list in the items (JSON) in ares

i am trying to filter the list when a letter is typed
the filter shows up but no letters are visible and no filtering happens
i am not sure what i am missing-i have tried this in so many ways and nothing seems to work -please help to get me passed this -it seems that there is not enough information on this
here is the code that i have now but still doesnt work:

setup: function() {
// Let's cache the current list of items and keep them around for filtering
this.allItems = this.$.list1.getItems();

// handler implementing a FilterField's onfilter event.
filterField1Filter: function(inSender, event) {
// get the filtered items
var filteredItems = this.fetchFilteredItems(event.filterString);
// set the list to display the filtered items

// really really simple filtering
fetchFilteredItems: function(inFilter) {
var items = [];
for (var i=0, l; l=this.allItems[i]; i++) {
if (l.label.toLowerCase().indexOf(inFilter) == 0) {
return items;
list1Listtap: function(event, inSender) {
} ,