Support translations in Fluxon components

lib/music_library_web/components/core_components.ex

@@ -118,4 +118,22 @@ defmodule MusicLibraryWeb.CoreComponents do
          "opacity-0 translate-y-4 sm:translate-y-0 sm:scale-95"}
     )
   end
+
+  def translate_error({msg, opts}) do
+    # When using gettext, we typically pass the strings we want
+    # to translate as a static argument:
+    #
+    #     # Translate the number of files with plural rules
+    #     dngettext("errors", "1 file", "%{count} files", count)
+    #
+    # However the error messages in our forms and APIs are generated
+    # dynamically, so we need to translate them by calling Gettext
+    # with our gettext backend as first argument. Translations are
+    # available in the errors.po file (as we use the "errors" domain).
+    if count = opts[:count] do
+      Gettext.dngettext(MusicLibraryWeb.Gettext, "errors", msg, msg, count, opts)
+    else
+      Gettext.dgettext(MusicLibraryWeb.Gettext, "errors", msg, opts)
+    end
+  end
 end