i18n: optimize performance

src/App.tsx

@@ -1,4 +1,4 @@
-import { Route, Router } from "@solidjs/router";
+import { Route } from "@solidjs/router";
 import { ThemeProvider } from "@suid/material";
 import {
   Component,
@@ -17,7 +17,12 @@ import {
 } from "./masto/clients.js";
 import { $accounts, updateAcctInf } from "./accounts/stores.js";
 import { useStore } from "@nanostores/solid";
-import { DateFnScope, useLanguage } from "./platform/i18n.jsx";
+import {
+  AppLocaleProvider,
+  createCurrentLanguage,
+  createCurrentRegion,
+  createDateFnLocaleResource,
+} from "./platform/i18n.jsx";
 import { useRegisterSW } from "virtual:pwa-register/solid";
 import {
   isJSONRPCResult,
@@ -67,7 +72,9 @@ const Routing: Component = () => {
 const App: Component = () => {
   const theme = useRootTheme();
   const accts = useStore($accounts);
-  const lang = useLanguage();
+  const lang = createCurrentLanguage();
+  const region = createCurrentRegion();
+  const dateFnLocale = createDateFnLocaleResource(region);
   const [serviceWorker, setServiceWorker] = createSignal<
     ServiceWorker | undefined
   >(undefined, { name: "serviceWorker" });
@@ -150,7 +157,13 @@ const App: Component = () => {
       }}
     >
       <ThemeProvider theme={theme}>
-        <DateFnScope>
+        <AppLocaleProvider
+          value={{
+            language: lang,
+            region: region,
+            dateFn: dateFnLocale,
+          }}
+        >
           <ClientProvider value={clients}>
             <ServiceWorkerProvider
               value={{
@@ -162,7 +175,7 @@ const App: Component = () => {
               <Routing />
             </ServiceWorkerProvider>
           </ClientProvider>
-        </DateFnScope>
+        </AppLocaleProvider>
       </ThemeProvider>
     </ErrorBoundary>
   );

src/platform/i18n.tsx

@@ -1,12 +1,12 @@
 import {
-  ParentComponent,
+  catchError,
   createContext,
   createMemo,
   createResource,
   useContext,
 } from "solid-js";
 import { match } from "@formatjs/intl-localematcher";
-import { Accessor, createEffect, createSignal } from "solid-js";
+import { Accessor } from "solid-js";
 import { $settings } from "../settings/stores";
 import { enGB } from "date-fns/locale/en-GB";
 import { useStore } from "@nanostores/solid";
@@ -17,13 +17,6 @@ import {
   type Template,
 } from "@solid-primitives/i18n";
 
-async function synchronised(
-  name: string,
-  callback: () => Promise<void> | void,
-): Promise<void> {
-  await navigator.locks.request(name, callback);
-}
-
 export const SUPPORTED_LANGS = ["en", "zh-Hans"] as const;
 
 export const SUPPORTED_REGIONS = ["en_US", "en_GB", "zh_CN"] as const;
@@ -38,14 +31,6 @@ export function autoMatchLangTag() {
   return match(Array.from(navigator.languages), SUPPORTED_LANGS, DEFAULT_LANG);
 }
 
-const DateFnLocaleCx = /* __@PURE__ */ createContext<Accessor<Locale>>(
-  () => enGB,
-);
-
-const cachedDateFnLocale: Record<string, Locale> = {
-  enGB,
-};
-
 export function autoMatchRegion() {
   const specifiers = navigator.languages.map((x) => x.split("-"));
 
@@ -70,7 +55,7 @@ export function autoMatchRegion() {
   return "en_GB";
 }
 
-export function useRegion() {
+export function createCurrentRegion() {
   const appSettings = useStore($settings);
 
   return createMemo(
@@ -100,53 +85,6 @@ async function importDateFnLocale(tag: string): Promise<Locale> {
   }
 }
 
-/**
- * Provides runtime values and fetch dependencies for date-fns locale
- */
-export const DateFnScope: ParentComponent = (props) => {
-  const [dateFnLocale, setDateFnLocale] = createSignal(enGB, {
-    name: "dateFnLocale",
-  });
-  const region = useRegion();
-
-  createEffect(() => {
-    const dateFnLocaleName = region();
-
-    if (cachedDateFnLocale[dateFnLocaleName]) {
-      setDateFnLocale(cachedDateFnLocale[dateFnLocaleName]);
-    } else {
-      synchronised("i18n-wrapper-load-date-fns-locale", async () => {
-        if (cachedDateFnLocale[dateFnLocaleName]) {
-          setDateFnLocale(cachedDateFnLocale[dateFnLocaleName]);
-          return;
-        }
-        const target = `date-fns/locale/${dateFnLocaleName}`;
-        try {
-          const mod = await importDateFnLocale(dateFnLocaleName);
-          cachedDateFnLocale[dateFnLocaleName] = mod;
-          setDateFnLocale(mod);
-        } catch (reason) {
-          console.error(
-            {
-              act: "load-date-fns-locale",
-              stat: "failed",
-              reason,
-              target,
-            },
-            "failed to load date-fns locale",
-          );
-        }
-      });
-    }
-  });
-
-  return (
-    <DateFnLocaleCx.Provider value={dateFnLocale}>
-      {props.children}
-    </DateFnLocaleCx.Provider>
-  );
-};
-
 /**
  * Get the {@link Locale} object for date-fns.
  *
@@ -155,11 +93,11 @@ export const DateFnScope: ParentComponent = (props) => {
  * @returns Accessor for Locale
  */
 export function useDateFnLocale(): Accessor<Locale> {
-  const cx = useContext(DateFnLocaleCx);
-  return cx;
+  const { dateFn } = useAppLocale();
+  return dateFn;
 }
 
-export function useLanguage() {
+export function createCurrentLanguage() {
   const settings = useStore($settings);
   return () => settings().language || autoMatchLangTag();
 }
@@ -179,7 +117,7 @@ type MergedImportedModule<T> = T extends []
 export function createStringResource<
   T extends ImportFn<Record<string, string | Template<any> | undefined>>[],
 >(...importFns: T) {
-  const language = useLanguage(); // TODO: this function costs to much, provide a global cache
+  const language = createCurrentLanguage();
   const cache: Record<string, MergedImportedModule<T>> = {};
 
   return createResource(
@@ -209,3 +147,38 @@ export function createTranslator<
 
   return [translator(res[0], resolveTemplate), res] as const;
 }
+
+export type AppLocale = {
+  dateFn: () => Locale;
+  language: () => string;
+  region: () => string;
+};
+
+const AppLocaleContext = /* @__PURE__ */ createContext<AppLocale>();
+
+export const AppLocaleProvider = AppLocaleContext.Provider;
+
+export function useAppLocale() {
+  const l = useContext(AppLocaleContext);
+  if (!l) {
+    throw new TypeError("app locale not found");
+  }
+  return l;
+}
+
+export function createDateFnLocaleResource(region: () => string) {
+  const [localeUncaught] = createResource(
+    region,
+    async (region) => {
+      return await importDateFnLocale(region);
+    },
+    { initialValue: enGB },
+  );
+
+  return createMemo(
+    () =>
+      catchError(localeUncaught, (reason) => {
+        console.error("fetch date-fns locale", reason);
+      }) ?? enGB,
+  );
+}