refactor progress

packages/number_utils/src/NumberFormatterCache.tsx

@@ -0,0 +1,43 @@
+/*
+ * 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/>.
+ */
+
+const numberFormatterCache = new Map<string, Intl.NumberFormat>();
+
+export function getNumberFormatter(
+	locale: string,
+	numberFormatOptions: Intl.NumberFormatOptions = {},
+): Intl.NumberFormat {
+	const cacheKey = buildFormatterCacheKey(locale, numberFormatOptions);
+	const cachedFormatter = numberFormatterCache.get(cacheKey);
+	if (cachedFormatter !== undefined) {
+		return cachedFormatter;
+	}
+
+	const formatter = new Intl.NumberFormat(locale, numberFormatOptions);
+	numberFormatterCache.set(cacheKey, formatter);
+	return formatter;
+}
+
+function buildFormatterCacheKey(locale: string, numberFormatOptions: Intl.NumberFormatOptions): string {
+	const optionEntries = Object.entries(numberFormatOptions)
+		.filter(([, value]) => value !== undefined)
+		.sort(([left], [right]) => left.localeCompare(right));
+	const optionKey = optionEntries.map(([key, value]) => `${key}:${String(value)}`).join('|');
+	return `${locale}|${optionKey}`;
+}