fix: correctly detect internal links when hash router is used

[teemingc]

fixes #13287

This PR fixes the client-side external link evaluation so that when using the hash router, accessing /index.html is considered an internal link. This prevents the page from reloading infinitely because the router incorrectly considered /index.html an external link.

There's also a slight doc change. Instead of suggesting all links start with /#/, suggesting links start with # allows the router to preserve the /index.html pathname. For example, links to /about should be #/about instead of /#/about so that it navigates to /index.html#/about.

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[Rich-Harris]

preview: https://svelte-dev-git-preview-kit-13296-svelte.vercel.app/

this is an automated message

[teemingc]

Seems to still infinitely reload if we embed the app in an iframe using srcdoc because the URL becomes about:srcdoc and the pathname is srcdoc.

EDIT: I think we'll just deal with the embedded app html text case in a different PR as there are more compatibility issues to deal with first #13226 . Embedding through a URL src seems to work fine.

[sateeshsai]

There's also a slight doc change. Instead of suggesting all links start with /#/, suggesting links start with # allows the router to preserve the /index.html pathname. For example, links to /about should be #/about instead of /#/about so that it navigates to /index.html#about.

This is great. I was going to raise an issue for this. '.../index.html/#/about' causes browser navigation in pages served by certain web servers.

Would this change work for urls that have the page name other than /index.html? For example, .../somepage.html

[teemingc]

Would this change work for urls that have the page name other than /index.html? For example, .../somepage.html

No, because the hash router build currently always generates an index.html page as the root page.

Wouldn't /index.html#about be expected to land on an element with id about on the /index.html page?

Yes, but you don't want to write all your links as href="/index.html#about" so you can just write href="#about" for the same effect.

[stephenlrandall]

No, because the hash router build currently always generates an index.html page as the root page.

This actually isn't documented at the moment, and it's not clear from the documentation how this interacts with the adapter-static fallback page option.

Wouldn't /index.html#about be expected to land on an element with id about on the /index.html page?

Yes, but you don't want to write all your links as href="/index.html#about" so you can just write href="#about" for the same effect.

So in the event someone has an "About this project" section on their home page with id="about" but also a page called "About" at /about, how would you link to each? Should href="#about" take you down to the section or over to the other page? Would something like href="#/about#authors" correctly take you to the "Authors" section over on /about? I apologize for all the questions, but it's not clear from the documentation how this is supposed to work.

[teemingc]

Wouldn't /index.html#about be expected to land on an element with id about on the /index.html page?

Yes, but you don't want to write all your links as href="/index.html#about" so you can just write href="#about" for the same effect.

So in the event someone has an "About this project" section on their home page with id="about" but also a page called "About" at /about, how would you link to each? Should href="#about" take you down to the section or over to the other page?

Sorry, I'm mistaken. The link should be href="#/about". The slash after the hash will cause it to navigate to a different page.

Would something like href="#/about#authors" correctly take you to the "Authors" section over on /about? I apologize for all the questions, but it's not clear from the documentation how this is supposed to work.

Yes, that will take you to authors section in the about page. Perhaps you can create a new issue and outline the hash router mechanics that require clarification in the documentation.

[sateeshsai]

Would this change work for urls that have the page name other than /index.html? For example, .../somepage.html

No, because the hash router build currently always generates an index.html page as the root page.

What is the recommended workaround if my html file isn't named index.html. E.g., test.html

[teemingc]

Would this change work for urls that have the page name other than /index.html? For example, .../somepage.html

No, because the hash router build currently always generates an index.html page as the root page.

What is the recommended workaround if my html file isn't named index.html. E.g., test.html

It should be easy enough to rename it in a post-build script. We should continue further discussion in the discussion boards or on discord