I love the idea of applications which exist in one file which you can run anywhere. I've been working towards this with my serverless platform; you can build complex data-driven apps with just one .html file and mostly declarative HTML markup (thanks to web-components which are loaded from a remote server). With modern browser features, you don't need a bundling system. Once you do away with it; a whole universe is opened up.

The ability to load .html files over the file:// protocol is a powerful, often neglected feature. In practice, it means you can double-click an HTML file and it runs an app in your browser instantly.

Sadly a lot of browser features are inaccessible from non-https contexts.

or you could use something like caddy (https reverse-proxy, local cert), and have a dedicated ws running in the background that serves your files

Don't most (all?) browsers consider file:// and localhost to be secure for the sake of enabling those features?

https://developer.mozilla.org/en-US/docs/Web/Security/Defens...

Unfortunately, no. CORS will block this on Chrome and Firefox.

https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/COR...

The security risk : https://www.mozilla.org/en-US/security/advisories/mfsa2019-2...

You need a local webserver. Or bundle everything in one html file.