jQuery: filter ul usando underscore.js

var todos = [];

$("ul li").each(function(index) {
   todos.push($(this).text());
});

$("#filter_def").keyup(function(){
    
    $("ul").html("");
   var srtSearch = $(this).val(); 

    var filtrados = _.filter(todos, function(txt){ return (new RegExp(srtSearch,'gi')).test(txt); });
    
    for(var i=0;i<filtrados.length;i++){
        $('ul').append('<li>'+filtrados[i]+'</li>');
    }

});

test rck:

http://jsfiddle.net/ric47121/Cvq4e/4/