Typeahead.js how to use filters

typeahead.js

$("#search").typeahead({
    remote: 'url',
    limit: 10,
    prefetch: {
       url:hotelPrefetchURL,
       filter:function(respData){
           var data = respData.data;
           return data;
       },
       ttl: 86400000        
    }
 });