Angular Directive watches page scroll w/ debounce feature

affix-w-debounce.js

'use strict';
angular.module('someApp').directive('simpleAffix', ['$window',function ($window) {
    return {
        scope: {
            onAffix: "&",
            onUnaffix: "&",
            affixHeight:"="
        },
        restrict: 'A',
        link: function (scope, element, attrs)
        {
            var fixed = false;
            scope.onUnaffix()
            angular.element($window).bind("scroll", function ()
            {
                if (fixed == false && scope.affixHeight < $window.pageYOffset) {
                    fixed = true;
                    scope.$apply(scope.onAffix());
                    return
                }
                if (fixed == true && scope.affixHeight >= $window.pageYOffset) {
                    fixed = false;
                    scope.$apply(scope.onUnaffix());
                }
            });
        }
    };
}]);

   angular.module('someApp').directive('rangeAffix', ['$window',function ($window) {
    return {
        scope: {
            onAffix: "&"
        },
        restrict: 'A',
        link: function (scope, element, attrs)
        {
            
            let fixed = false;
            function scrollHandler() {
                let _boundingClientRect = element[0].getBoundingClientRect();

                let _top = _boundingClientRect.top;
                let _bottom = _boundingClientRect.bottom;
                if (_bottom >= $window.innerHeight/2 &&  $window.innerHeight/2 >= _top ) {
                    scope.$apply(scope.onAffix());
                    return
                }
            }
            angular.element($window).bind("scroll", debounce(scrollHandler,10));
        }
    };
   }]);

   function debounce(func, wait) {
    var timeout;
    return function () {
        var context = this, args = arguments;
        var later = function () {
            timeout = null;
            func.apply(context, args);
        };

        if (!timeout) func.apply(context, args);
        clearTimeout(timeout);
        timeout = setTimeout(later, wait);
    };
}