Permalink conflict with React Router in subfolder

Question

I managed to get it working by placing the following in an .htaccess file in my React app folder:

 <IfModule mod_rewrite.c>
     RewriteEngine on
     # Don’t rewrite files or directories
     RewriteCond %{REQUEST_FILENAME} -f [OR]
     RewriteCond %{REQUEST_FILENAME} -d
     RewriteRule ^ – [L]
     # Rewrite everything else to index.html to allow html5 state links
     RewriteRule ^ index.html [L]
 </IfModule>

Also WP custom permalinks work as well.