Preview mentions (#5571)

Co-authored-by: Tom Moor <tom.moor@gmail.com>

shared/utils/date.ts

@@ -1,4 +1,24 @@
+/* eslint-disable import/no-duplicates */
 import { subDays, subMonths, subWeeks, subYears } from "date-fns";
+import {
+  de,
+  enUS,
+  es,
+  faIR,
+  fr,
+  it,
+  ja,
+  ko,
+  nl,
+  ptBR,
+  pt,
+  pl,
+  ru,
+  tr,
+  vi,
+  zhCN,
+  zhTW,
+} from "date-fns/locale";
 import type { DateFilter } from "../types";
 
 export function subtractDate(date: Date, period: DateFilter) {
@@ -80,3 +100,35 @@ export function getCurrentDateTimeAsString(locales?: Intl.LocalesArgument) {
     minute: "numeric",
   });
 }
+
+const locales = {
+  de_DE: de,
+  en_US: enUS,
+  es_ES: es,
+  fa_IR: faIR,
+  fr_FR: fr,
+  it_IT: it,
+  ja_JP: ja,
+  ko_KR: ko,
+  nl_NL: nl,
+  pt_BR: ptBR,
+  pt_PT: pt,
+  pl_PL: pl,
+  ru_RU: ru,
+  tr_TR: tr,
+  vi_VN: vi,
+  zh_CN: zhCN,
+  zh_TW: zhTW,
+};
+
+/**
+ * Returns the date-fns locale object for the given user language preference.
+ *
+ * @param language The user language
+ * @returns The date-fns locale.
+ */
+export function dateLocale(language: string | null | undefined) {
+  return language ? locales[language] : undefined;
+}
+
+export { locales };