Add languages to metrics API endpoint

hooks/useLanguageNames.js

@@ -0,0 +1,34 @@
+import { useState, useEffect } from 'react';
+import { useRouter } from 'next/router';
+import { get } from 'lib/web';
+import enUS from 'public/language/en-US.json';
+
+const languageNames = {
+  'en-US': enUS,
+};
+
+export default function useLanguageNames(locale) {
+  const [list, setList] = useState(languageNames[locale] || enUS);
+  const { basePath } = useRouter();
+
+  async function loadData(locale) {
+    const { ok, data } = await get(`${basePath}/language/${locale}.json`);
+
+    if (ok) {
+      languageNames[locale] = data;
+      setList(languageNames[locale]);
+    } else {
+      setList(enUS);
+    }
+  }
+
+  useEffect(() => {
+    if (!languageNames[locale]) {
+      loadData(locale);
+    } else {
+      setList(languageNames[locale]);
+    }
+  }, [locale]);
+
+  return list;
+}