AnugalrJS infinit-scroll directive Idea

infinit-scroll.js

app.directive('infinitScroll', ['$parse', function($parse) {

    return {
        restrict : 'A',
        link: function ($scope, $el, $attr) {

            var registered = false;
            var pollInProgress = false;
            var nextPageFn = $parse($attr.infinitScroll);
            var options = $scope.$eval($attr.infinitScrollOptions)||{};

            options.offset = options.offset || 0;

            //========================================
            //
            //
            //========================================
            function pollNextPage() {

                if(!$scope || !$scope.$root) {
                    deregister();
                    return;
                }

                if(pollInProgress) {
                    return;
                }

                if(!$el.is(':visible')) {
                    return;
                }

                try {

                    pollInProgress = true;

                    var offsetTop = $el.offset().top;
                    var scrollBottom = $(window).scrollTop() + $(window).height();

                    if(offsetTop <= (scrollBottom + options.offset)) { // Reached

                        $scope.safeApply(function(){

                            var result = nextPageFn($scope);

                            if(result===false)
                                deregister();
                        });
                    }
                }
                catch (e) {

                    throw e;
                }
                finally {

                    pollInProgress = false;
                }
            }

            //========================================
            //
            //
            //========================================
            function register(){

                if(registered)
                    return;

                registered = true;

                $(window  ).on('load resize', pollNextPage);
                $(document).on('load resize scroll', pollNextPage);
            }

            //========================================
            //
            //
            //========================================
            function deregister(){
                if(!registered)
                    return;

                $(window  ).off('load resize', pollNextPage);
                $(document).off('load resize scroll', pollNextPage);
                registered = false;
            }

            //========================================
            //
            //
            //========================================
            $scope.$watch(function(){ // On digest
                if(registered) {
                    pollNextPage();
                }
            });

            //========================================
            //
            //
            //========================================
            $scope.safeApply = function(fn) {
              var phase = this.$root.$$phase;
              if(phase == '$apply' || phase == '$digest') {
                if(fn && (typeof(fn) === 'function')) {
                  fn();
                }
              } else {
                this.$apply(fn);
              }
            };

            register();
        }
    };
}]);