1 files changed, 30 insertions, 0 deletions
diff --git a/packages/anastasis-webui/src/hooks/useLang.ts b/packages/anastasis-webui/src/hooks/useLang.ts
new file mode 100644
index 000000000..5b02c5255
--- /dev/null
+++ b/packages/anastasis-webui/src/hooks/useLang.ts
@@ -0,0 +1,30 @@
+/*
+ This file is part of GNU Anastasis
+ (C) 2021-2022 Anastasis SARL
+
+ GNU Anastasis is free software; you can redistribute it and/or modify it under the
+ terms of the GNU Affero General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Anastasis is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
+
+ You should have received a copy of the GNU Affero General Public License along with
+ GNU Anastasis; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+import { useNotNullLocalStorage } from "./useLocalStorage.js";
+
+function getBrowserLang(): string | undefined {
+  if (window.navigator.languages) return window.navigator.languages[0];
+  if (window.navigator.language) return window.navigator.language;
+  return undefined;
+}
+
+export function useLang(
+  initial?: string,
+): [string, (s: string) => void, boolean] {
+  const defaultLang = (getBrowserLang() || initial || "en").substring(0, 2);
+  return useNotNullLocalStorage("lang-preference", defaultLang);
+}