try {
    if (fs.existsSync(uploadPath + filename.substring(0, filename.lastIndexOf('.')) + '.mp4')) {
        res.end('<b><i>' + filename + '</i></b> already exists in the directory.');
    }
    else {
        const fstream = fs.createWriteStream(path.join(cfg.tempStoragePath, filename));
        file.pipe(fstream);
        console.log("nfile_type: " + file_type);
        filename = filename.substring(0, filename.lastIndexOf('.'));

        // On finish of the copying file to temp location
        fstream.on('close', () => {
            hbjs.spawn({
                input: cfg.tempStoragePath + filename + '.' + file_type,
                output: uploadPath + filename + '.mp4'
            })
                .on('error', err => {
                    // invalid user input, no video found etc
                    console.log('error! No input video found at: n: ' + cfg.tempStoragePath + filename + '.' + file_type);
                    res.send('Conversion of the file, <b><i>' + filename + '</i></b>, from <b>.' + file_type + '</b>' + ' to <b>.mp4</b> failed because no input video was found at: n: ' + cfg.tempStoragePath + filename + '.' + file_type);
                })
                .on('progress', progress => {
                    progress_percent = (Number(progress.percentComplete) * 2 <= 100) ? Number(progress.percentComplete) * 2 : 100;
                    eta = progress.eta.split(/[a-zA-Z]/);
                    minutes = ((+eta[0]) * 60 + (+eta[1])) / 2;
                    console.log('Percent complete: %d, ETA: %d ///// %s ==> mp4', progress_percent, minutes, file_type);
                })
                .on('end', end => {
                    console.log('Conversion from .' + file_type + ' to .mp4 complete.');
                    //delete the temp file
                    fs.unlink(cfg.tempStoragePath + filename + '.' + file_type);
                    let new_path = uploadPath + filename + '.mp4';
                    let stat = fs.statSync(new_path);
                    console.log(`Upload of '${filename}' finished`);
                    if(Number(progress_percent) === Number(100))
                        res.send('The file, <b><i>' + filename + '</i></b>, has been converted from <b>.' + file_type + '</b>' + ' to <b>.mp4</b> complete.');
                    })
                });
            }
    }

    catch (err) {
        res.end(err);
    }

request = new XMLHttpRequest();
request.onreadystatechange = function () {
    if (request.readyState === XMLHttpRequest.DONE && request.status === 200) {
        showConversionModal('<p>' + request.responseText + '</p>', 'done');
    }
};
showSomeModal('something');
request.open("POST", client.clientHost + ":" + client.clientPort + "/uploadVideoService");
formData = new FormData();
formData.append("file", files[0], files[0].name);
request.send(formData);