Create a click handler only when needed

Question

I have a small directive where the is a button, and a hidden input file.

I would like to create a click handler when the button is clicked, so I would click the input file that is hidden.

My directive:

app.directive('fileUpload', function($timeout) {
    return {
        restrict: 'E',
        templateUrl: "templates/partials/file-upload.html",

        controller: ['$scope', function ($scope) {

            $scope.fileInput = "";

            $scope.clickedImageUpload = function () {
                console.log($scope.fileInput);

                $scope.fileInput.click();
            };

        }],

        link: function(scope, element, attrs) {
            console.log(element);

            var fileInput = angular.element().find('.invisibleFileInput').html;
            scope.fileInput = element[0].getElementsByClassName('invisibleFileInput');
            console.log(scope.fileInput);
        }
    };
});