A little further ahead with the app in Alpine

resources/assets/v4/util/format.js

@@ -0,0 +1,99 @@
+/*
+ * format.js
+ * Copyright (c) 2023 james@firefly-iii.org
+ *
+ * This file is part of Firefly III (https://github.com/firefly-iii).
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import {format} from 'date-fns'
+import {
+    bg,
+    cs,
+    da,
+    de,
+    el,
+    enGB,
+    enUS,
+    es,
+    ca,
+    fi,
+    fr,
+    hu,
+    id,
+    it,
+    ja,
+    ko,
+    nb,
+    nn,
+    nl,
+    pl,
+    ptBR,
+    pt,
+    ro,
+    ru,
+    sk,
+    sl,
+    sv,
+    tr,
+    uk,
+    vi,
+    zhTW,
+    zhCN
+} from 'date-fns/locale'
+
+const locales = {
+    bg,
+    cs,
+    da,
+    de,
+    el,
+    enGB,
+    enUS,
+    es,
+    ca,
+    fi,
+    fr,
+    hu,
+    id,
+    it,
+    ja,
+    ko,
+    nb,
+    nn,
+    nl,
+    pl,
+    ptBR,
+    pt,
+    ro,
+    ru,
+    sk,
+    sl,
+    sv,
+    tr,
+    uk,
+    vi,
+    zhTW,
+    zhCN
+}
+
+// by providing a default string of 'PP' or any of its variants for `formatStr`
+// it will format dates in whichever way is appropriate to the locale
+export default function (date, formatStr = 'PP') {
+    let locale = window.__localeId__.replace('_', '');
+    return format(date, formatStr, {
+        locale: locales[locale] ?? locales[locale.slice(0, 2)] ?? locales['enUS'] // or global.__localeId__
+    })
+}