Implement correct normalization of locales in i18n

packages/osd-i18n/src/core/i18n.test.ts

@@ -178,7 +178,7 @@ describe('I18n engine', () => {
         'en-us'
       );
 
-      expect(i18n.getLocale()).toBe('en-us');
+      expect(i18n.getLocale()).toBe('en-US');
       expect(i18n.getTranslation()).toEqual({
         messages: {
           ['a.b.c']: 'bar',
@@ -246,9 +246,19 @@ describe('I18n engine', () => {
       expect(i18n.getLocale()).toBe('foo');
     });
 
-    test('should normalize passed locale', () => {
-      i18n.setLocale('en-US');
-      expect(i18n.getLocale()).toBe('en-us');
+    test('should normalize basic locale', () => {
+      i18n.setLocale('It-iT');
+      expect(i18n.getLocale()).toBe('it-IT');
+    });
+
+    test('should normalize simple locale', () => {
+      i18n.setLocale('en-LATN-us_PRIVATE-variant');
+      expect(i18n.getLocale()).toBe('en-Latn-US');
+    });
+
+    test('should normalize complex locale', () => {
+      i18n.setLocale('FR-CA-X-FALLBACK-und-u@keyword=calendarKey');
+      expect(i18n.getLocale()).toBe('fr-CA');
     });
   });
 
@@ -280,8 +290,8 @@ describe('I18n engine', () => {
     });
 
     test('should normalize passed locale', () => {
-      i18n.setDefaultLocale('en-US');
-      expect(i18n.getDefaultLocale()).toBe('en-us');
+      i18n.setDefaultLocale('eN-uS');
+      expect(i18n.getDefaultLocale()).toBe('en-US');
     });
 
     test('should set "en" locale as default for IntlMessageFormat and IntlRelativeFormat', () => {

packages/osd-i18n/src/core/i18n.ts

@@ -44,6 +44,16 @@ const EN_LOCALE = 'en';
 const translationsForLocale: Record<string, Translation> = {};
 const getMessageFormat = memoizeIntlConstructor(IntlMessageFormat);
 
+/* A locale code is made of several components:
+ *    * lang: The two- and three-letter lower-case language code follows the ISO 639-1 and ISO 639-2/3 standards, respectively.
+ *    * script: The optional four-letter title-case code follows the ISO 15924 standard for representing writing systems.
+ *    * region: The two-letter upper-case region code follows the ISO 3166-1 alpha-2 standard.
+ *
+ * Ref: https://www.rfc-editor.org/rfc/rfc5646.txt
+ * Note: While case carries no distinction with locale codes, proper formatting is recommended.
+ */
+const localeParser = /^(?<lang>[a-z]{2,3})(?:-(?<script>[a-z]{4}))?(?:-(?<region>[a-z]{2}|[0-9]{3}))?(?:[_@\-].*)?$/i;
+
 let defaultLocale = EN_LOCALE;
 let currentLocale = EN_LOCALE;
 let formats = EN_FORMATS;
@@ -64,8 +74,16 @@ function getMessageById(id: string): string | undefined {
  * Normalizes locale to make it consistent with IntlMessageFormat locales
  * @param locale
  */
-function normalizeLocale(locale: string) {
-  return locale.toLowerCase();
+export function normalizeLocale(locale: string) {
+  const { lang, script, region } = localeParser.exec(locale)?.groups || {};
+  // If parsing failed or the language code was not extracted, return the locale
+  if (!lang) return locale;
+
+  const parts = [lang.toLowerCase()];
+  if (script) parts.push(script[0].toUpperCase() + script.slice(1).toLowerCase());
+  if (region) parts.push(region.toUpperCase());
+
+  return parts.join('-');
 }
 
 /**

packages/osd-i18n/src/loader.ts

@@ -34,6 +34,7 @@
 
 import { unique } from './core/helper';
 import { Translation } from './translation';
+import { normalizeLocale } from './core';
 
 const TRANSLATION_FILE_EXTENSION = '.json';
 
@@ -69,7 +70,9 @@
     );
   }
 
-  return path.basename(fullFileName, TRANSLATION_FILE_EXTENSION);
+  const basename = path.basename(fullFileName, TRANSLATION_FILE_EXTENSION);
+
+  return normalizeLocale(basename);
 }
 
 /**
@@ -131,6 +134,15 @@
   return Object.keys(translationsRegistry);
 }
 
+/**
+ * Check if a locale is registered; returns undefined if i18n is uninitialized
+ */
+export function isRegisteredLocale(locale: string): boolean | undefined {
+  const normalizedLocale = normalizeLocale(locale);
+
+  return translationsRegistry?.hasOwnProperty(normalizedLocale);
+}
+
 /**
  * Returns translation messages by specified locale
  * @param locale

src/core/public/application/scoped_history.test.ts

@@ -30,23 +30,8 @@
 
 import { ScopedHistory } from './scoped_history';
 import { createMemoryHistory } from 'history';
-import { getLocaleInUrl } from '../locale_helper';
-import { i18n } from '@osd/i18n';
-
-jest.mock('../locale_helper', () => ({
-  getLocaleInUrl: jest.fn(),
-}));
-
-jest.mock('@osd/i18n', () => ({
-  i18n: {
-    getLocale: jest.fn(),
-  },
-}));
 
 describe('ScopedHistory', () => {
-  beforeEach(() => {
-    (getLocaleInUrl as jest.Mock).mockReturnValue('en');
-  });
   describe('construction', () => {
     it('succeeds if current location matches basePath', () => {
       const gh = createMemoryHistory();
@@ -373,49 +358,4 @@ describe('ScopedHistory', () => {
       expect(gh.length).toBe(4);
     });
   });
-
-  describe('locale handling', () => {
-    let originalLocation: Location;
-
-    beforeEach(() => {
-      originalLocation = window.location;
-      delete (window as any).location;
-      window.location = { href: 'http://localhost/app/wow', reload: jest.fn() } as any;
-      (i18n.getLocale as jest.Mock).mockReturnValue('en');
-    });
-
-    afterEach(() => {
-      window.location = originalLocation;
-      jest.resetAllMocks();
-    });
-
-    it('reloads the page when locale changes', () => {
-      const gh = createMemoryHistory();
-      gh.push('/app/wow');
-      const h = new ScopedHistory(gh, '/app/wow');
-      // Use the 'h' variable to trigger the listener
-      h.push('/new-page');
-
-      // Mock getLocaleInUrl to return a different locale
-      (getLocaleInUrl as jest.Mock).mockReturnValue('fr');
-
-      // Simulate navigation
-      gh.push('/app/wow/new-page');
-
-      expect(window.location.reload).toHaveBeenCalled();
-    });
-
-    it('does not reload the page when locale changes', () => {
-      const gh = createMemoryHistory();
-      gh.push('/app/wow');
-
-      // Mock getLocaleInUrl to return a different locale
-      (getLocaleInUrl as jest.Mock).mockReturnValue('en');
-
-      // Simulate navigation
-      gh.push('/app/wow/new-page');
-
-      expect(window.location.reload).not.toHaveBeenCalled();
-    });
-  });
 });

src/core/public/application/scoped_history.ts

@@ -39,8 +39,6 @@ import {
   Href,
   Action,
 } from 'history';
-import { i18n } from '@osd/i18n';
-import { getLocaleInUrl } from '../locale_helper';
 
 /**
  * A wrapper around a `History` instance that is scoped to a particular base path of the history stack. Behaves
@@ -309,7 +307,6 @@ export class ScopedHistory<HistoryLocationState = unknown>
    * state. Also forwards events to child listeners with the base path stripped from the location.
    */
   private setupHistoryListener() {
-    const currentLocale = i18n.getLocale() || 'en';
     const unlisten = this.parentHistory.listen((location, action) => {
       // If the user navigates outside the scope of this basePath, tear it down.
       if (!location.pathname.startsWith(this.basePath)) {
@@ -318,14 +315,6 @@ export class ScopedHistory<HistoryLocationState = unknown>
         return;
       }
 
-      const localeValue = getLocaleInUrl(window.location.href);
-
-      if (localeValue !== currentLocale) {
-        // Force a full page reload
-        window.location.reload();
-        return;
-      }
-
       /**
        * Track location keys using the same algorithm the browser uses internally.
        * - On PUSH, remove all items that came after the current location and append the new location.