Switch to the another language on the same page? - middleman

Question

I am trying to add a language changer for Middleman and it's not generating the correct link. My default and root is English.
url_for("/#{current_page.path}", locale: :ja)
I would expect the equivalent for the current page in JA which is the same URL with JA prepended. Does anyone know how to fix this?

Answer 1

I'm a middleman beginner, but after doing a bunch of Googling it seems like this is a fairly common issue. I've tried to look through the middleman sources to see if I could find a solution, but I've been unable. I'm kinda disappointed about this, because it looks like middleman has first-class support for localizations. Being unable to easily link from one to another seems like a surprising omission.
What I've done is make a little helper that can swap localizations in paths, if needed.
def change_locale_in_path(path, locale)
locale_prefix = I18n.locale
path.gsub(/^#{locale_prefix}/, locale.to_s)
end
This isn't a great solution, though. It will need to be adjusted if you change the i18n :path, and won't work unless you mount_at_root: false. But, it worked well enough for me to move on. I really would love to see a better solution.
I found a few GitHub issues that seem to reference this problem. Here's one.

Answer 2

I am using the following helper to generate a URL for the current page in a different language. It was originally based on this gist, and then tweaked it a bit so that it works regardless of whether mount_at_root is used.
def current_url_for_locale(loc)
url_regex = /\A\/(?:(#{I18n.available_locales.join('|')})\/)?/
locale_root = url_for('/', locale: loc)
current_page.url.gsub(url_regex, '').blank? ?
locale_root :
current_page.url.gsub(url_regex, locale_root)
end