Documentation for Field Enhancers

What do I need to do to write my own enhancer in a custom module? Specifically how do I register them?

@woldtwerk Custom field enhancers should be saved as /my_module/src/Plugin/jsonapi/FieldEnhancer/MyFieldEnhancer.php.

After that, rebuilding the Drupal cache (drush cr) should cause the field enhancer to be picked up automatically.

I successfully set up an enhancer just now by referencing the other ones in code and reading this issue. I just wanted to second the observation in #4 that doTransform and doUndoTransform seem to be named the opposite of what they do. doUndoTransform is where you will want to modify the data for API output. I didn't dig around too much to figure out why, but I guess it has to do with the more general intent of Shaper\DataAdaptor\DataAdaptorTransformerTrait from e0ipso/shaper, where doTransform is meant to transform "incoming" data, and doUndoTransform is meant to perform the inverse transformation on "outgoing" data. Our use cases in this issue are all for outgoing data. At least that's my interpretation.