webserver - How to custom handle a file not being found when using go static file server?

Question

So I'm using a go server to serve up a single page web application.

This works for serving all the assets on the root route. All the CSS and HTML are served up correctly.

fs := http.FileServer(http.Dir("build"))
http.Handle("/", fs)

So when the URL is http://myserverurl/index.html or http://myserverurl/styles.css, it serves the corresponding file.

But for a URL like http://myserverurl/myCustompage, it throws 404 if myCustompage is not a file in the build folder.

How do I make all routes for which a file does not exist serve index.html?

It is a single page web application and it will render the appropriate screen once the html and js are served. But it needs index.html to be served on routes for which there is no file.

How can this be done?

Answer 1

Waitting for answers