Doing server side rendering of HTML templates I find myself using Java's Locale class (via various helper functions) to render language codes (ISO 639-1), script codes (ISO 15294), and country codes (ISO 3166) as their name (i.e. "en" -> "English") in a manner that respects the current user's selected locale.
Now, moving some stuff to client side rendering (with Angular JS), I'm a bit unsure of how to approach this. Doing the code-to-name conversion on the server side and sending locale-aware JSON is one option, but it would add quite a lot of complexity to how various bits of data get JSONified (by having to pass the locale through lots of layers of functions, mainly.)
On the other hand, I can see how a full-on client side version of the Java Locale class would involve sending lots of data to the client, most of which wouldn't get used most of the time.
Are there any emerging best-practices for doing this kind of stuff with largely single-page apps, or any super libraries that would solve my problem in well fell swoop?