Asset upload with Laravel 5.5

Hi, I'm using grapesjs - 0.14.15 on my server. Trying to upload images in two different ways:

        assetManager: {
            upload: '/uploadAsset',
            assets: [],
            uploadText: 'Ziehe Dateien hier her oder klicke hier.',
            autoAdd: true,
            addBtnText: 'ext. Bild',
            modalTitle: 'Bild auswählen',
            dropzone: true,
            openAssetsOnDrop: true,
            headers: {
                'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
            },

and with:

        assetManager: {
            upload: '/uploadAsset',
            assets: [],
            uploadText: 'Ziehe Dateien hier her oder klicke hier.',
            autoAdd: true,
            addBtnText: 'ext. Bild',
            modalTitle: 'Bild auswählen',
            dropzone: true,
            openAssetsOnDrop: true,
            headers: {
                'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
            },
            uploadFile: function (e) {
                var files = e.dataTransfer ? e.dataTransfer.files : e.target.files;
                var formData = new FormData();
                for (var i in files) {
                    formData.append('file-' + i, files[i]) //containing all the selected images from local
                }
                $.ajax({
                    url: '/uploadAsset',
                    type: 'POST',
                    data: formData,
                    contentType: false,
                    crossDomain: true,
                    headers: {
                        'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
                    },
                    dataType: 'json',
                    mimeType: "multipart/form-data",
                    processData: false,
                    success: function (result) {
                        var myJSON = [];
                        $.each(result['data'], function (key, value) {
                            myJSON[key] = value;
                        });
                        var images = myJSON;
                        editor.AssetManager.add(images); //adding images to asset
                    }
                });

            }
        }

In my PHP file I only want to return the files array using:

    public function uploadAsset(Request $request)
    {
        return $request;
    }

But it's allways empty. Please help - thank you. Regards Frantischek