Fixed name to camel case

js/lib/helpers/userOnline.js

@@ -0,0 +1,13 @@
+import icon from 'flarum/helpers/icon';
+
+/**
+ * The `useronline` helper displays a green circle if the user is online
+ *
+ * @param {User} user
+ * @return {Object}
+ */
+export default function userOnline(user) {
+    if (user.lastSeenTime() && user.isOnline()) {
+        return <span className="UserOnline">{icon('circle')}</span>;
+    }
+}