1 // Copyright 2015-present 650 Industries. All rights reserved.
2 
3 import Foundation
4 
5 @objc
6 public class EXTextDirectionController: NSObject {
7   class func isRTLPreferredForCurrentLocale() -> Bool {
8     return NSLocale.characterDirection(forLanguage: NSLocale.preferredLanguages.first ?? "en-US") == NSLocale.LanguageDirection.rightToLeft
9   }
10 
11   @objc
12   public class func setSupportsRTL(_ supportsRTL: Bool) {
13     // These keys are used by React Native here: https://github.com/facebook/react-native/blob/main/React/Modules/RCTI18nUtil.m
14     // We set them before React loads to ensure it gets rendered correctly the first time the app is opened.
15     // On iOS we need to set both forceRTL and allowRTL so apps don't have to include localization strings.
16     UserDefaults.standard.set(supportsRTL, forKey: "RCTI18nUtil_allowRTL")
17     UserDefaults.standard.set(supportsRTL ? isRTLPreferredForCurrentLocale() : false, forKey: "RCTI18nUtil_forceRTL")
18     UserDefaults.standard.synchronize()
19   }
20 }
21