Method showDialog

src/notebooks/export/exportDialog.ts:21–67

(
        format: ExportFormat,
        source: Uri | undefined,
        defaultFileName?: string
    )

 */
export class ExportDialog {
    public async showDialog(
        format: ExportFormat,
        source: Uri | undefined,
        defaultFileName?: string
    ): Promise<Uri | undefined> {
        // map each export method to a set of file extensions
        let fileExtensions: { [name: string]: string[] } = {};
        let extension: string | undefined;
        switch (format) {
            case ExportFormat.python:
                fileExtensions = PythonExtensions;
                extension = '.py';
                break;

            case ExportFormat.pdf:
                extension = '.pdf';
                fileExtensions = PDFExtensions;
                break;

            case ExportFormat.html:
                extension = '.html';
                fileExtensions = HTMLExtensions;
                break;

            case ExportFormat.ipynb:
                extension = '.ipynb';
                const filtersKey = localize.DataScience.exportDialogFilter;
                fileExtensions[filtersKey] = ['ipynb'];
                break;

            default:
                return;
        }

        const targetFileName =
            defaultFileName || !source
                ? defaultFileName || ''
                : `${path.basename(source.path, path.extname(source.path))}${extension}`;

        const options: SaveDialogOptions = {
            defaultUri: await this.getDefaultUri(source, targetFileName),
            saveLabel: localize.DataScience.exportButtonTitle,
            filters: fileExtensions
        };

        return window.showSaveDialog(options);
    }

    private async getDefaultUri(source: Uri | undefined, targetFileName: string): Promise<Uri | undefined> {
        if (source && source.scheme === 'untitled' && isWebExtension()) {