How to make angularjs and multer friends without angular-file-upload?

Question

Angular

Hello, how to transfer a file from angular without using third-party directives?
1. There is a form with text fields and a field with an image, I process the image like this, I display the result in base64 in the preview, and I want to transfer the file itself to multer - $scope.order.image

fileReader.readAsDataUrl($scope.file, $scope)
            .then(function(result) {
                $scope.order.image = $scope.file;
                $scope.order.image_preview = result;
            });

What is the best way to do this? load the file separately on onChange, get the generated file name from multer and pass it to the database as a separate request when submitting the form? Maybe someone has some solutions how to make them friends without using additional libraries from npm ?!
Thank you.