nst blob = new Blob([currentMindmap.markdown], {type: 'text/markdown'});
                    const url = URL.createObjectURL(blob);
                    const a = document.createElement('a');
                    a.href = url;
                    a.download = 'mindmap.md';
                    document
                        .body
                        .appendChild(a);
                    a.click();
                    document
                        .body
                        .removeChild(a);
         