feat(app): Add 'getAppLanguageCode' and 'getAppLanguageTag'

Author: philet

app/android/src/main/java/com/capacitorjs/plugins/app/AppPlugin.java

@@ -14,6 +14,8 @@
 import com.getcapacitor.annotation.CapacitorPlugin;
 import com.getcapacitor.util.InternalUtils;
 
+import java.util.Locale;
+
 @CapacitorPlugin(name = "App")
 public class AppPlugin extends Plugin {
 
@@ -115,6 +117,20 @@ public void minimizeApp(PluginCall call) {
         call.resolve();
     }
 
+    @PluginMethod
+    public void getAppLanguageCode(PluginCall call) {
+        JSObject ret = new JSObject();
+        ret.put("value", Locale.getDefault().getLanguage());
+        call.resolve(ret);
+    }
+
+    @PluginMethod
+    public void getAppLanguageTag(PluginCall call) {
+        JSObject ret = new JSObject();
+        ret.put("value", Locale.getDefault().toLanguageTag());
+        call.resolve(ret);
+    }
+
     /**
      * Handle ACTION_VIEW intents to store a URL that was used to open the app
      * @param intent

app/ios/Plugin/AppPlugin.m

@@ -10,4 +10,6 @@
            CAP_PLUGIN_METHOD(getState, CAPPluginReturnPromise);
            CAP_PLUGIN_METHOD(minimizeApp, CAPPluginReturnPromise);
            CAP_PLUGIN_METHOD(removeAllListeners, CAPPluginReturnPromise);
+           CAP_PLUGIN_METHOD(getAppLanguageCode, CAPPluginReturnPromise);
+           CAP_PLUGIN_METHOD(getAppLanguageTag, CAPPluginReturnPromise);
 )

app/ios/Plugin/AppPlugin.swift

@@ -104,4 +104,27 @@ public class AppPlugin: CAPPlugin {
     @objc func minimizeApp(_ call: CAPPluginCall) {
         call.unimplemented()
     }
+  
+    @objc func getAppLanguageCode(_ call: CAPPluginCall) {
+      
+        // According to https://developer.apple.com/news/?id=u2cfuj88, the current
+        // app language is returned by 'Bundle.main.preferredLocalizations.first'.
+        // Fallback to device language if app language is not defined.
+      
+        let appLanguageWithFallbackToDeviceLanguage =
+            Bundle.main.preferredLocalizations.first ?? Locale.preferredLanguages[0]
+        let code = String(appLanguageWithFallbackToDeviceLanguage.prefix(2))
+
+        call.resolve([
+            "value": code
+        ])
+    }
+
+    @objc func getAppLanguageTag(_ call: CAPPluginCall) {
+        let tag = Bundle.main.preferredLocalizations.first ?? Locale.preferredLanguages[0]
+
+        call.resolve([
+            "value": tag
+        ])
+    }
 }

app/src/definitions.ts

@@ -130,6 +130,24 @@ export type URLOpenListener = (event: URLOpenListenerEvent) => void;
 export type RestoredListener = (event: RestoredListenerEvent) => void;
 export type BackButtonListener = (event: BackButtonListenerEvent) => void;
 
+export interface GetLanguageCodeResult {
+  /**
+   * Two character language code.
+   *
+   * @since 5.1.0
+   */
+  value: string;
+}
+
+export interface LanguageTag {
+  /**
+   * Returns a well-formed IETF BCP 47 language tag.
+   *
+   * @since 5.1.0
+   */
+  value: string;
+}
+
 export interface AppPlugin {
   /**
    * Force exit the app. This should only be used in conjunction with the `backButton` handler for Android to
@@ -171,6 +189,20 @@ export interface AppPlugin {
    */
   minimizeApp(): Promise<void>;
 
+  /**
+   * Get the app specific language locale code.
+   *
+   * @since 5.1.0
+   */
+  getAppLanguageCode(): Promise<GetLanguageCodeResult>;
+
+  /**
+   * Get the app specific language locale tag.
+   *
+   * @since 5.1.0
+   */
+  getAppLanguageTag(): Promise<LanguageTag>;
+
   /**
    * Listen for changes in the app or the activity states.
    *

app/src/web.ts

@@ -1,6 +1,6 @@
 import { WebPlugin } from '@capacitor/core';
 
-import type { AppInfo, AppPlugin, AppLaunchUrl, AppState } from './definitions';
+import type { AppInfo, AppPlugin, AppLaunchUrl, AppState, GetLanguageCodeResult, LanguageTag } from './definitions';
 
 export class AppWeb extends WebPlugin implements AppPlugin {
   constructor() {
@@ -44,4 +44,16 @@ export class AppWeb extends WebPlugin implements AppPlugin {
       this.notifyListeners('resume', null);
     }
   };
+
+  async getAppLanguageCode(): Promise<GetLanguageCodeResult> {
+    return {
+      value: navigator.language.split('-')[0].toLowerCase(),
+    };
+  }
+
+  async getAppLanguageTag(): Promise<LanguageTag> {
+    return {
+      value: navigator.language,
+    };
+  }
 }