feat: dynamic languages (#27869)

Co-authored-by: xantin <github@xantin.be>

web/src/lib/utils/i18n.ts

@@ -1,8 +1,8 @@
-import { langs } from '$lib/constants';
+import type { Lang } from '$lib/constants';
 import { locale, t, waitLocale } from 'svelte-i18n';
 import { get, type Unsubscriber } from 'svelte/store';
 
-export async function getFormatter() {
+export const getFormatter = async () => {
   let unsubscribe: Unsubscriber | undefined;
   await new Promise((resolve) => {
     unsubscribe = locale.subscribe((value) => value && resolve(value));
@@ -11,23 +11,122 @@ export async function getFormatter() {
 
   await waitLocale();
   return get(t);
-}
+};
+
+const modules = import.meta.glob('$i18n/*.json');
+
+const fileCodes = Object.keys(modules)
+  .map((path) => path.match(/\/(\w+)\.json$/)?.[1])
+  .filter(Boolean) as string[];
+
+const convertBCP47 = (code: string) => code.replace('_', '-');
+
+export const langCodes = fileCodes.map((code) => convertBCP47(code));
 
 // https://github.com/kaisermann/svelte-i18n/blob/780932a3e1270d521d348aac8ba03be9df309f04/src/runtime/stores/locale.ts#L11
-function getSubLocales(refLocale: string) {
-  return refLocale
+const getSubLocales = (locale: string) => {
+  return locale
     .split('-')
     .map((_, i, arr) => arr.slice(0, i + 1).join('-'))
     .reverse();
-}
+};
 
-export function getClosestAvailableLocale(locales: readonly string[], allLocales: readonly string[]) {
+export const getClosestAvailableLocale = (locales: readonly string[], allLocales: readonly string[]) => {
   const allLocalesSet = new Set(allLocales);
   return locales.find((locale) => getSubLocales(locale).some((subLocale) => allLocalesSet.has(subLocale)));
-}
+};
 
-export const langCodes = langs.map((lang) => lang.code);
+export const getPreferredLocale = () => getClosestAvailableLocale(navigator.languages, langCodes);
 
-export function getPreferredLocale() {
-  return getClosestAvailableLocale(navigator.languages, langCodes);
-}
+const rtlCodes = new Set([
+  'ae',
+  'aeb',
+  'aii',
+  'ajp',
+  'apc',
+  'apd',
+  'ar',
+  'ar_BH',
+  'ar_DZ',
+  'ar_EG',
+  'ar_KW',
+  'ar_LY',
+  'ar_MA',
+  'ar_SA',
+  'ar_YE',
+  'ara',
+  'arc',
+  'arq',
+  'ars',
+  'arz',
+  'ave',
+  'bal',
+  'bcc',
+  'bgn',
+  'bqi',
+  'ckb',
+  'ckb_IR',
+  'dv',
+  'egy',
+  'fa',
+  'fa_AF',
+  'fas',
+  'glk',
+  'ha',
+  'he',
+  'heb',
+  'khw',
+  'kmr',
+  'ks',
+  'ku',
+  'lrc',
+  'luz',
+  'ms_Arab',
+  'mzn',
+  'nqo',
+  'pa_PK',
+  'pal',
+  'per',
+  'phn',
+  'pnb',
+  'prs',
+  'ps',
+  'rhg',
+  'sam',
+  'sd',
+  'sdh',
+  'skr',
+  'syc',
+  'syr',
+  'ug',
+  'ur',
+  'ur_IN',
+  'urd',
+  'yi',
+]);
+
+const capitalize = (string: string) =>
+  string
+    .split(' ')
+    .map((word) => word.charAt(0).toUpperCase() + word.slice(1))
+    .join(' ');
+
+const nonIntlNames: Record<string, string> = {
+  mfa: 'Malay (Pattani)',
+  bi: 'Bislama',
+};
+
+const getLanguageName = (code: string) =>
+  nonIntlNames[code] ?? capitalize(new Intl.DisplayNames([code], { type: 'language' }).of(code) ?? code);
+
+export const langs: Lang[] = [
+  ...fileCodes
+    .map((code) => ({
+      name: getLanguageName(convertBCP47(code)),
+      code,
+      loader: () => import(`$i18n/${code}.json`),
+      rtl: rtlCodes.has(code),
+    }))
+    .sort((a, b) => a.code.localeCompare(b.code)),
+  { name: 'Development (keys only)', code: 'dev', loader: () => Promise.resolve({ default: {} }) },
+];