Filestremove函数中的Bootstrap Fileinput js问题

Question

当我们点击删除按钮时，它首次运行，第二次它（event.target.files）对于新上传的图像变为空。 请在下面用angular 2写的代码

    $("#input-fcount-1").fileinput({
        uploadUrl: "/file-upload-batch/2",
        maxFileCount: 4,
        validateInitialCount: true,
        overwriteInitial: false,
        initialPreview: [
            "<img class='kv-preview-data file-preview-image' src='https://placeimg.com/800/460/nature'>",
            "<img class='kv-preview-data file-preview-image' src='https://placeimg.com/800/460/nature'>",
            "<img class='kv-preview-data file-preview-image' src='https://placeimg.com/800/460/nature'>"
        ]
 })
        .on('filepreremove', function(event, id, index) {
                        var deletedFileName = event.target.files[index].name;
        });

请提出任何建议或我遗漏了代码。