ffects and don't save any information
that is used on subsequent runs of the function.</p>
<p>In some situations, however, you may need to write a helper that interacts with
the rest of your application. You can create class-based helpers that have
access to services in your application, and can optionally save state as well,
although this is usually unnecessary and error-prone.</p>
<p>To create a class-based helper, rather than exporting a simple function, you
should export a subclass of <a href="https://a