How to correctly download pdf and docx file in React JS?

I am trying to download docx or pdf file in React JS(depending on server response) when I get the response from the server. Backend is implemented in Python/Flask.

When I try to download the file, it downloads but damaged and corrupted.

React JS

function downloadDocument(downloadLink, downloadType) {
 const documentBlob = new Blob([downloadLink], { type: downloadType });
 const url = window.URL.createObjectURL(documentBlob);
 const anchor = document.createElement('a');
 anchor.href = url;
 anchor.download = document_title;
 document.body.appendChild(anchor);
 anchor.click();
 document.body.removeChild(anchor);
 window.URL.revokeObjectURL(url) ;
}

Backend Python/Flask

@app.route('/download_document_docx/<request_document_id>', methods=['GET'])
@token_required
def download_document_docx(current_user, request_document_id):
    '''
    Docx document preparation code
    '''
    return send_file(docx_file_path, as_attachment=True, mimetype="application/vnd.openxmlformats-officedocument.wordprocessingml.document")