Preventing nginx from adding the trailing slash onto subdirs

nginx.vhost.conf

server {
...
  # asset files (.css, .js, .png etc.) are not served correctly...
  location /developer {
    rewrite /(.*)/? /$1/index.html break;
    root /mnt/www/docs/public;
  }

  # ... so they get a separate entry
  # Being a more specific match, nginx uses this one for assets.
  location /developer/assets {
    root /mnt/www/docs/public;
  }
...
}

Want to avoid if conditions...