How to upload file using BusBoy in combination with ExpressJS, NodeJS and TypeScript?

We believe adaptation to the latest trends in the coding. Hence, we have been using TypeScript in all our major projects. We love code the the frontend in Angular 2, React and the dynamic backend in NodeJS. Here's a small example we have created using TypeScript, NodeJS and ExpressJS to upload a file with BusBoy using Typescript.