Restore vanilla components

app/javascript/mastodon/features/compose/util/counter.js

@@ -0,0 +1,9 @@
+import { urlRegex } from './url_regex';
+
+const urlPlaceholder = 'xxxxxxxxxxxxxxxxxxxxxxx';
+
+export function countableText(inputText) {
+  return inputText
+    .replace(urlRegex, urlPlaceholder)
+    .replace(/(^|[^\/\w])@(([a-z0-9_]+)@[a-z0-9\.\-]+[a-z0-9]+)/ig, '$1@$3');
+};