From e72cc8b9885643ea5279c58b244e065298587c68 Mon Sep 17 00:00:00 2001
From: kazuya kawaguchi <kawakazu80@gmail.com>
Date: Thu, 12 Oct 2023 14:45:33 +0900
Subject: [PATCH] fix: refactor `validateLangTag` (#23)

---
 src/shared.ts | 3 +--
 src/shim.d.ts | 3 +++
 2 files changed, 4 insertions(+), 2 deletions(-)
 create mode 100644 src/shim.d.ts

diff --git a/src/shared.ts b/src/shared.ts
index 70bf362..3f0837a 100644
--- a/src/shared.ts
+++ b/src/shared.ts
@@ -42,8 +42,7 @@ export function toLocale(val: string | Intl.Locale): Intl.Locale {
  */
 export function validateLangTag(lang: string): boolean {
   try {
-    // TODO: if we have a better way to validate the language tag, we should use it.
-    new Intl.Locale(lang)
+    Intl.getCanonicalLocales(lang)
     return true
   } catch {
     return false
diff --git a/src/shim.d.ts b/src/shim.d.ts
new file mode 100644
index 0000000..4f541fa
--- /dev/null
+++ b/src/shim.d.ts
@@ -0,0 +1,3 @@
+declare namespace Intl {
+  function getCanonicalLocales(locales: string | string[]): string[]
+}