autocompletion in vscode

vscode_autocompletion_fileopen_dialogue.ts

    const commandCreateFile = vscode.commands.registerCommand("extension.dired.createFile", async () => {
        // list files of provider.dirname
        const quickPick = vscode.window.createQuickPick();
        quickPick.canSelectMany = false;
        quickPick.placeholder = "Filename:";
        let dirname = provider.dirname ?? path.normalize(".");
        quickPick.items = [{ label: dirname }];
        let fileName = quickPick.value;
        let disposables: vscode.Disposable[] = [];
        try {
            await new Promise<void>(resolve => {
                quickPick.placeholder = "Create Or Open Files"
                disposables.push(
                    quickPick.onDidChangeValue(directoryOrFile => {
                        if (!path.isAbsolute(directoryOrFile))
                        {
                            if (provider.dirname == undefined)
                                return
                            directoryOrFile = path.join(provider.dirname, directoryOrFile);
                        }
                        let files: vscode.QuickPickItem[] = []
                        let dirname: string
                        try {
                            let stat = fs.statSync(directoryOrFile);
                            files.push({label : directoryOrFile});
                            if (stat.isDirectory()) {
                                dirname = directoryOrFile;
                            }
                            else {
                                dirname = path.dirname(directoryOrFile);
                            }
                        }
                        catch
                        {
                            dirname = path.dirname(directoryOrFile);
                        }
                        fs.readdirSync(dirname).forEach(
                            fileName => files.push( {label : path.join(dirname, fileName)})
                        )
                        quickPick.items = files;
                    }),
                    quickPick.onDidAccept(() => {
                        if (quickPick.selectedItems.length == 0 || quickPick.selectedItems[0].label == quickPick.value) {
                            fileName = quickPick.value;
                            quickPick.hide();
                            resolve();
                        }
                        else {
                            quickPick.value = quickPick.selectedItems[0].label;
                        }
                    }),
                    quickPick.onDidHide(() => {
                        quickPick.dispose();
                        resolve();
                    })
                );
                quickPick.show();
            });
        }
        finally {
            disposables.forEach(d => d.dispose());
        }

        vscode.window.showInformationMessage(`${fileName} success`);
        if (fileName == undefined) {
            return;
        }
        let openFile: boolean = false;
        try {
            let stat = await fs.promises.stat(fileName);
            if (stat.isDirectory()) {
                provider.openDir(fileName);
            }
            else {
                openFile = true;
            }
        }
        catch {
            openFile = true;
        }
        if (openFile) {
            let document = await vscode.workspace.openTextDocument(fileName);
            await vscode.window.showTextDocument(document);
            provider.reload();
        }
    });