date localization

apps/client/src/lib/date-locale.ts

@@ -0,0 +1,62 @@
+import { format as dateFnsFormat, type Locale } from "date-fns";
+import {
+  de,
+  enUS,
+  es,
+  fr,
+  it,
+  ja,
+  ko,
+  nl,
+  ptBR,
+  ru,
+  uk,
+  zhCN,
+} from "date-fns/locale";
+import { useTranslation } from "react-i18next";
+import i18n from "@/i18n.ts";
+
+const LOCALE_MAP: Record<string, Locale> = {
+  "de-DE": de,
+  "en-US": enUS,
+  "es-ES": es,
+  "fr-FR": fr,
+  "it-IT": it,
+  "ja-JP": ja,
+  "ko-KR": ko,
+  "nl-NL": nl,
+  "pt-BR": ptBR,
+  "ru-RU": ru,
+  "uk-UA": uk,
+  "zh-CN": zhCN,
+};
+
+export function getDateFnsLocale(language?: string): Locale {
+  const lang = language ?? i18n.language ?? "en-US";
+  return LOCALE_MAP[lang] ?? LOCALE_MAP[lang.split("-")[0]] ?? enUS;
+}
+
+export function useDateFnsLocale(): Locale {
+  const { i18n: instance } = useTranslation();
+  return getDateFnsLocale(instance.language);
+}
+
+function isEnglishLocale(locale: Locale): boolean {
+  return locale.code === "en-US" || locale.code?.startsWith("en") === true;
+}
+
+/**
+ * Picks `enUSPattern` for the English locale and `localizedPattern` for every
+ * other locale. Keeps existing en-US output byte-identical while letting other
+ * languages use date-fns localized format tokens (P, PP, p, PPp, …).
+ */
+export function formatLocalized(
+  date: Date | number | string,
+  enUSPattern: string,
+  localizedPattern: string,
+  locale?: Locale,
+): string {
+  const effective = locale ?? getDateFnsLocale();
+  const pattern = isEnglishLocale(effective) ? enUSPattern : localizedPattern;
+  return dateFnsFormat(new Date(date), pattern, { locale: effective });
+}

apps/client/src/lib/time.ts

@@ -1,17 +1,25 @@
-import { formatDistanceStrict } from "date-fns";
-import { format, isToday, isYesterday } from "date-fns";
+import { formatDistanceStrict, isToday, isYesterday } from "date-fns";
 import i18n from "@/i18n.ts";
+import { formatLocalized, getDateFnsLocale } from "@/lib/date-locale.ts";
 
 export function timeAgo(date: Date) {
-  return formatDistanceStrict(new Date(date), new Date(), { addSuffix: true });
+  return formatDistanceStrict(new Date(date), new Date(), {
+    addSuffix: true,
+    locale: getDateFnsLocale(),
+  });
 }
 
 export function formattedDate(date: Date) {
+  const locale = getDateFnsLocale();
   if (isToday(date)) {
-    return i18n.t("Today, {{time}}", { time: format(date, "h:mma") });
+    return i18n.t("Today, {{time}}", {
+      time: formatLocalized(date, "h:mma", "p", locale),
+    });
   } else if (isYesterday(date)) {
-    return i18n.t("Yesterday, {{time}}", { time: format(date, "h:mma") });
+    return i18n.t("Yesterday, {{time}}", {
+      time: formatLocalized(date, "h:mma", "p", locale),
+    });
   } else {
-    return format(date, "MMM dd, yyyy, h:mma");
+    return formatLocalized(date, "MMM dd, yyyy, h:mma", "PPp", locale);
   }
 }