Wrap a request in a promise

I have a custom Templating system that requires me to have a file per path (/api, /url2 . . ;)
And i would like to get the content of a file uploaded, for example

module.exports = async (req, res) =>
{
var UploadManager = Router.GetModel("UploadManager", req);
if (req.method === "POST")
{
var uploadedFiles = await multer().single('avatar')(req,res);
console.log(multerUpload);
}
}

I know this code will not work but i want to give an example so maybe i can get an answer. Thanks =)