scroll-to-end

import angular = require('angular');

function OnScrollToEndDirective($window, $document) {
    'use strict';

    return {
        restrict: 'A',
        link: link,
    };

    function link(scope, element, attrs) {
        angular.element($window).bind('scroll', scrollHandler);

        element.on('$destroy', function() {
            angular.element($window).unbind('scroll', scrollHandler);
        });

        let above = true;

        function scrollHandler() {
            if (above && $document[0].body.scrollHeight - $window.scrollY - $window.innerHeight < 500) {
                above = false;
                scope.$apply(function() {
                    scope.$eval(attrs.onScrollToEnd);
                });
            } else {
                above = true;
            }

        }
    }
}

OnScrollToEndDirective.$inject = ['$window', '$document'];
export = OnScrollToEndDirective;