refactor progress

packages/list_utils/src/ListFormattingSupport.tsx

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2026 Fluxer Contributors
+ *
+ * This file is part of Fluxer.
+ *
+ * Fluxer 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 of the License, or
+ * (at your option) any later version.
+ *
+ * Fluxer 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 Fluxer. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+export function isIntlListFormatSupported(): boolean {
+	return typeof Intl !== 'undefined' && typeof Intl.ListFormat !== 'undefined';
+}
+
+export function isIntlListFormatLocaleSupported(locale: string): boolean {
+	if (!isIntlListFormatSupported()) {
+		return false;
+	}
+
+	try {
+		return Intl.ListFormat.supportedLocalesOf([locale]).length > 0;
+	} catch {
+		return false;
+	}
+}