snapshot of https://github.com/jitsi/jitsi-meet.git @ fd1749dd28f4138aa80234fc7f311b19aaffa0e7 (2026-09-15)

react/features/base/i18n/languageDetector.web.ts

@@ -0,0 +1,70 @@
+import BrowserLanguageDetector from 'i18next-browser-languagedetector';
+import { noop } from 'lodash-es';
+
+import LANGUAGES_RESOURCES from '../../../../lang/languages.json';
+
+import configLanguageDetector from './configLanguageDetector';
+
+// Map from lowercased key → original key (e.g. 'fr-ca' → 'fr-CA') for
+// case-insensitive lookup that still returns the exact casing i18next expects.
+const SUPPORTED_LANGUAGES = new Map(
+    Object.keys(LANGUAGES_RESOURCES).map(lang => [ lang.toLowerCase(), lang ])
+);
+
+/**
+ * Custom querystring language detector that validates the raw `lang` query
+ * parameter against the application's supported-language allowlist before
+ * returning it. This prevents unsanitized user-controlled input from reaching
+ * i18next internals (defence-in-depth on top of i18next's own whitelist).
+ */
+const safeLangQueryDetector = {
+    name: 'safeLangQuery',
+    cacheUserLanguage: noop,
+    lookup() {
+        const value = new URLSearchParams(window.location.search).get('lang');
+
+        const lang = value && SUPPORTED_LANGUAGES.get(value.toLowerCase());
+
+        if (lang) {
+            return lang;
+        }
+
+        return undefined;
+    }
+};
+
+/**
+ * The ordered list (by name) of language detectors to be utilized as backends
+ * by the singleton language detector for Web.
+ *
+ * @type {Array<string>}
+ */
+const order = [
+    safeLangQueryDetector.name,
+    'localStorage'
+];
+
+// Allow i18next to detect the system language reported by the Web browser
+// itself.
+interfaceConfig.LANG_DETECTION && order.push('navigator');
+
+// Default use configured language
+order.push(configLanguageDetector.name);
+
+/**
+ * The singleton language detector for Web.
+ */
+const languageDetector
+    = new BrowserLanguageDetector(
+        /* services */ null,
+        /* options */ {
+            caches: [ 'localStorage' ],
+            lookupLocalStorage: 'language',
+            lookupQuerystring: 'lang',
+            order
+        });
+
+languageDetector.addDetector(safeLangQueryDetector);
+languageDetector.addDetector(configLanguageDetector);
+
+export default languageDetector;