services.AddSingleton<NodeServer.NodeServer>(
    sp => new NodeServer.NodeServer(sp,
        new NodeServer.NodeServerOptions
        {
            // This must be unique to avoid multiple process accessing same
            // folder conflicts
            TempFolder = "D:\\temp\\" + Guid.NewGuid(),
            // ProGet private registry url
            NPMRegistry = "https://private-proget.company.com/npm/PRIVATE",
            PrivatePackages = new string[] {
                "@company/package@1.0.1",
                "@company/core@1.0.1"
            }
        }));

    [HttpGet("template/{version}/{name}")]
    public async Task<string> ProcessTemplate(
        [FromRoute] string name,
        [FromRoute] string version,
        [FromBody] EmailModel model,
        [FromService] NodeServer.NodeServer server
    ) {

        // get node services from the installed package version
        // if version does not exist, it will download package
        // along with all its dependencies
        var package = await 
            server.GetInstalledPackageASync($"@company/template@{version}");

        var nodeServices = package.NodeServices;

        return await nodeServices.InvokeExportAsync(
            "index.js",
            "default",
            new {
                fromName: "Sender",
                fromAddress: "senderEmail",
                body: model
            });

    }