getRelativeLocaleUrl() should correctly identify and parse paths that are already localized to one language, so they can be "translated" to a different language.

[victor-marino]

Body

Summary

The getRelativeLocaleUrl() currently only works if you pass a "clean", unlocalized path to it. It's not able to change the language for an already localized path. This makes it a bit challenging and counter-intuitive to implement a reliable language switcher in our websites.

Background & Motivation

In my site, I have two languages set up:

• Spanish as the default language at /
• English at /en/

I have a navbar that correctly links to the right pages depending on which language the user is browsing now, which is easy by using getRelativeLocaleUrl() since the navbar links always point to a known, static page that I can hard-code. E.g.:

getRelativeLocaleUrl(Astro.currentLocale!, "about")
getRelativeLocaleUrl(Astro.currentLocale!, "blog")
...

However, things get trickier when implementing the "language switcher" control. The expected behaviour is that, if the user is browsing the about page and they switch languages, they should be taken to the same page they're currently viewing, but in the other language.

The issue is, the only function that I can find to get the current URL path is Astro.url.pathname, and that will return the full path, including any localization subfolders. But the getRelativeLocaleUrl() seems to always expect a "clean" path without any language subfolders.

So if the user is browsing a page in the default language without any localized subfolder, such as mysite.com/about/, all will be good. The function will return /about/, which I can correctly pass like:

getRelativeLocaleUrl('en', Astro.url.pathname)' // returns a valid link: mysite.com/en/about/

However, if the user is browsing the English version at mysite.com/en/about/ and I want to take him to the default (es) language of that page, that doesn't work.

getRelativeLocaleUrl('es', '/en/about') // --> returns the same link: mysite.com/en/about/

as getRelativeLocaleUrl() assumes the provided path is always a default path free of subdomains, and so it doesn't modify it.

Right now, I'm using a little one-liner helper to strip the locale from a path (if present) before passing it to getRelativeLocaleUrl():

currentPathWithoutLocale = currentPath.replace('/' + currentLocale + '/', '/');

But I'm not sure how reliable that will be going forward, and either way I think this functionality should be built-in.

Goals

In my view, we should either:

• Have the getRelativeLocaleUrl() function correctly identify and parse localized paths natively

and/or:

• Have a complimentary method to Astro.url.pathname, something like Astro.url.unlocalizedPathname, that returns the current path without the language subfolder, so that it can always be reliably passed to getRelativeLocaleUrl().

Does this make sense? Or am I missing something and there is perhaps an existing, 'native' way of doing this already?