Moved code into src folder. Added build for component library.

src/components/hooks/useLocale.js

@@ -0,0 +1,65 @@
+import { useEffect } from 'react';
+import { useRouter } from 'next/router';
+import { httpGet, setItem } from 'next-basics';
+import { LOCALE_CONFIG } from 'lib/constants';
+import { getDateLocale, getTextDirection } from 'lib/lang';
+import useStore, { setLocale } from 'store/app';
+import useForceUpdate from 'components/hooks/useForceUpdate';
+import enUS from 'public/intl/messages/en-US.json';
+
+const messages = {
+  'en-US': enUS,
+};
+
+const selector = state => state.locale;
+
+export function useLocale() {
+  const locale = useStore(selector);
+  const { basePath } = useRouter();
+  const forceUpdate = useForceUpdate();
+  const dir = getTextDirection(locale);
+  const dateLocale = getDateLocale(locale);
+
+  async function loadMessages(locale) {
+    const { ok, data } = await httpGet(`${basePath}/intl/messages/${locale}.json`);
+
+    if (ok) {
+      messages[locale] = data;
+    }
+  }
+
+  async function saveLocale(value) {
+    if (!messages[value]) {
+      await loadMessages(value);
+    }
+
+    setItem(LOCALE_CONFIG, value);
+
+    document.getElementById('__next')?.setAttribute('dir', getTextDirection(value));
+
+    if (locale !== value) {
+      setLocale(value);
+    } else {
+      forceUpdate();
+    }
+  }
+
+  useEffect(() => {
+    if (!messages[locale]) {
+      saveLocale(locale);
+    }
+  }, [locale]);
+
+  useEffect(() => {
+    const url = new URL(window?.location?.href);
+    const locale = url.searchParams.get('locale');
+
+    if (locale) {
+      saveLocale(locale);
+    }
+  }, []);
+
+  return { locale, saveLocale, messages, dir, dateLocale };
+}
+
+export default useLocale;