This issue is a feature request asking to add a catch-all capability to the static mode.
The static server should redirect every possible url pointed to the function to the root path.
Example: http:127.0.0.1:8080/function/hello/subpath -> http:127.0.0.1:8080/function/hello

In Nginx, this is accomplished with the try_files directive.
https://docs.nginx.com/nginx/admin-guide/web-server/serving-static-content/#trying-several-options

Current Behaviour

Currently, requesting any function subpath, i.e http:127.0.0.1:8080/function/hello/subpath, will return a 404 error.

Context

This capability is mandatory in the context of Single Page Applications, like React.js apps.
Using Hash History adding # in the URL brings other issues and is not a valid solution for professional modern web applications.
A Single Page Application technically only have a single index.html, and a server should redirect every possible url pointed to the domain at this index.html located at the root.

In Nginx, we implement a catch-all rule for SPA like so:

location / {
    try_files  $uri  $uri/  index.html;
}

Link to your project or a code example to reproduce issue

Minimal React.js Single Page Application packaged for OpenFaaS with the dockerfile template and the watchdog in static mode: https://github.com/Janaka-Steph/react-spa-openfaas