We are planning to create a set of REST services, but it's very possible that your server will also have to serve some static files, such as images, PDFs, and so on. On principle, you could do this by hand by setting specific routes for each static asset, and then writing a function that would read the required file and stream its contents to the client; we did something like that in the Working with streams to process requests section in the previous chapter.
However, this is such a common and reiterative task that Express provides a simpler solution; let's look at how we can simply serve static files.
An even better solution would be to have another server, such as nginx, in your stack and have it handle static files. Standard servers are much better at handling this type of simple request, and will leave your Node code free to handle more complex, demanding tasks.