katowulf

// this will be much more efficient than $watch()
app.factory('FilteredArray', function($firebaseArray) {
  function FilteredArray(ref, filterFn) {
    this.filterFn = filterFn;
    return $firebaseArray.call(this, ref);
  }
  FilteredArray.prototype.$$added = function(snap) {
    var rec = $firebaseArray.prototype.$$added.call(this, snap);
    if( !this.filterFn || this.filterFn(rec) ) {
      return rec;

katowulf

var app = angular.module('app', ['firebase']);

app.controller('ctrl', function($scope) {
  var ref = new Firebase('https://fbutil.firebaseio.com/paginate');
  $scope.scrollItems = $scrollArray(ref, 'number');
});

app.factory('$scrollArray', function($firebaseArray) {
  return function(ref, field) {
    // create a special scroll ref