go-locale

Go library used to retrieve the current locale(s) of the operating system.

OS Support

• Windows
  Using GetUserDefaultLocaleName and GetSystemDefaultLocaleName.

• macOS
  Using [Bundle preferredLocalizations], falling back to calling defaults read -g AppleLocale and defaults read -g AppleLanguages (since environment variables like LANG are not usually set on macOS).

• Unix-like systems (Linux, BSD, etc.)
  Using the LANGUAGE, LC_ALL, LC_MESSAGES and LANG environment variables.

• WASM (JavaScript)
  Using navigator.language and navigator.languages.

• iOS
  Using [NSLocale preferredLanguages].

• Android
  Using getResources().getConfiguration().getLocales for Android N or later, or getResources().getConfiguration().locale otherwise.

  Note: for Android, you'll first need to call SetRunOnJVM, depending on which mobile framework you're using:

  • For Fyne:

    import (
    	"fyne.io/fyne/v2/driver"
    	"github.com/jeandeaual/go-locale"
    )
    
    func init() {
    	locale.SetRunOnJVM(func(fn func(vm, env, ctx uintptr) error) error {
    		driver.RunNative(func(ctx interface{}) error {
    			and := ctx.(*driver.AndroidContext)
    			return fn(and.VM, and.Env, and.Ctx)
    		})
    		return nil
    	})
    }

  • For gomobile:

    import (
    	"golang.org/x/mobile/app"
    	"github.com/jeandeaual/go-locale"
    )
    
    func init() {
    	locale.SetRunOnJVM(app.RunOnJVM)
    }

Usage

GetLocales

GetLocales returns the user's preferred locales, by order of preference, as a slice of IETF BCP 47 language tag (e.g. []string{"en-US", "fr-FR", "ja-JP"}).

This works if the user set multiple languages on macOS and other Unix systems. Otherwise, it returns a slice with a single locale.

userLocales, err := locale.GetLocales()
if err == nil {
	fmt.Println("Locales:", userLocales)
}

This can be used with golang.org/x/text or go-i18n to set the localizer's language preferences:

import (
	"github.com/jeandeaual/go-locale"
	"golang.org/x/text/message"
)

func main() {
	userLocales, _ := locale.GetLocales()
	p := message.NewPrinter(message.MatchLanguage(userLocales...))
	...
}

import (
	"github.com/jeandeaual/go-locale"
	"github.com/nicksnyder/go-i18n/v2/i18n"
	"golang.org/x/text/language"
)

func main() {
	userLocales, _ := locale.GetLocales()
	bundle := i18n.NewBundle(language.English)
	localizer := i18n.NewLocalizer(bundle, userLocales...)
	...
}

For a complete example, see here.

GetLocale

GetLocale returns the current locale as defined in IETF BCP 47 (e.g. "en-US").

userLocale, err := locale.GetLocale()
if err == nil {
	fmt.Println("Locale:", userLocale)
}

GetLanguage

GetLanguage returns the current language as an ISO 639 language code (e.g. "en").

userLanguage, err := locale.GetLanguage()
if err == nil {
	fmt.Println("Language:", userLocale)
}

GetRegion

GetRegion returns the current language as an ISO 3166 country code (e.g. "US").

userRegion, err := locale.GetRegion()
if err == nil {
	fmt.Println("Region:", userRegion)
}

Aknowledgements

Inspired by jibber_jabber.