Not possible to run SvelteKit SPA inside a subfolder of a web server

[GELight]

Describe the bug

Its not possible to run a SvelteKit SAP application in a subfolder of a web server like this:

Folder example:
wwwroot/project_folder

Url example:
http://mydomain.de/project_folder

Reproduction

1. Create new sveltekit app with npm init svelte@next my-app
2. Add adapter @sveltejs/adapter-static to the project and the sveltekit configuration
3. Add the path configuration for the config.kit.paths

path: {
   base: '/project_folder',
   assets: 'http://localhost/project_folder'
}

4. Run npm run build to create a production version of the project
5. Create an example web server root folder out of the project mkdir wwwroot
6. Copy the created production my-app/build folder into the wwwroot
7. Rename wwwroot/build folder to my-app/project_folder
8. Go into wwwroot folder and start a web server by http-server
9. Open URL http://localhost/project_folder
10. Click any link to route to other sub route

Problem is:
The router will not change the pages per Javascript. Instead a standard behaviour of the browser with a default page refresh (no javascript) from / to /blog (for example) happens. The result is a 404 error because the page does not exist.

Logs

No errors in log...

System Info

Tested in Linux Mint...
Tested in Windows...

Severity

blocking all usage of SvelteKit

Additional Information

Question from my side:

1. Is there any configuration to running my SAP inside a sub folder in my web server?
2. Its possible to configure the router for using hash in URL like in Vue.js - hash-mode?
3. Maybe its needed any server rewrite rule configuration for the project folder wwwroot/project_folder?

The problem is ... only one webserver ( IIS ) is possible.
Therefore only working with sub folders is possible in our company.

[dominikg]

Please use discussions and/or discord https://svelte.dev/chat for questions

[edwinspire]

I had the same problem with my project with Sveltekit and adapter-static when uploading it on my IIS where I have several apps in other folders.

What I did is place in svelte.config.js:

import adapter from '@sveltejs/adapter-static';
import { vitePreprocess } from '@sveltejs/kit/vite';

const config = {
	preprocess: vitePreprocess(),

	kit: {
		adapter: adapter({
			fallback: 'index.html',
		}),
		paths: {base: '/svelte'},
		prerender: { entries: [] }
	}
};

export default config;

Where the base "/svelte" is the name of the folder where I saved the files generated by Sveltekit en IIS.

It worked.