Memoize NumberFormat as well

packages/react-i18n/src/i18n.ts

@@ -1,4 +1,5 @@
 import {
+  formatDate,
   isLessThanOneHourAgo,
   isLessThanOneMinuteAgo,
   isLessThanOneWeekAgo,
@@ -41,7 +42,6 @@ import {
   memoizedNumberFormatter,
   memoizedPluralRules,
 } from './utilities';
-import {formatDate} from './temporary-format-date';
 
 export interface NumberFormatOptions extends Intl.NumberFormatOptions {
   as?: 'number' | 'currency' | 'percent';

packages/react-i18n/src/utilities/translate.tsx

@@ -17,6 +17,17 @@ const MISSING_TRANSLATION = Symbol('Missing translation');
 const PLURALIZATION_KEY_NAME = 'count';
 const SEPARATOR = '.';
 
+const numberFormats = new Map();
+export const memoizedNumberFormatter = function(locale, options = {}) {
+  const key = numberFormatCacheKey(locale, options);
+  if (numberFormats.has(key)) {
+    return numberFormats.get(key);
+  }
+  const i = new Intl.NumberFormat(locale, options);
+  numberFormats.set(key, i);
+  return i;
+};
+
 export const PSEUDOTRANSLATE_OPTIONS: PseudotranslateOptions = {
   startDelimiter: '{',
   endDelimiter: '}',
@@ -30,19 +41,13 @@ export interface TranslateOptions<Replacements = {}> {
   pseudotranslate?: boolean | string;
 }
 
-function numberFormatter(
+function numberFormatCacheKey(
   locale: string,
   options: Intl.NumberFormatOptions = {},
 ) {
-  return new Intl.NumberFormat(locale, options);
+  return `${locale}${JSON.stringify(options)}`;
 }
 
-export const memoizedNumberFormatter = memoizeFn(
-  numberFormatter,
-  (locale: string, options: Intl.NumberFormatOptions = {}) =>
-    `${locale}${JSON.stringify(options)}`,
-);
-
 function pluralRules(locale: string, options: Intl.PluralRulesOptions = {}) {
   return new Intl.PluralRules(locale, options);
 }