static files with express.js

I want to serve index.html and /media subdirectory as static files. The index file should be served both at /index.html and / URLs.

I have

web_server.use("/media", express.static(__dirname + '/media'));
web_server.use("https://stackoverflow.com/", express.static(__dirname));

but the second line apparently serves the entire __dirname, including all files in it (not just index.html and media), which I don’t want.

I also tried

web_server.use("https://stackoverflow.com/", express.static(__dirname + '/index.html'));

but accessing the base URL / then leads to a request to web_server/index.html/index.html (double index.html component), which of course fails.

Any ideas?

By the way, I could find absolutely no documentation in Express on this topic (static() + its params)… frustrating. A doc link is also welcome.