Reactive Fields

Let one field respond to another as your users type. Reactive Fields adds a react_on option to any Avo field, so a city select can repopulate when the country changes, a slug can fill itself from a name, and a price can recompute the moment a quantity is edited, all on the same form. It's all plain Ruby, no JavaScript to write and no Stimulus controller to wire up.

When a watched field changes, the form posts itself back over Turbo and Avo re-renders only the reacting fields. Point a field at one dependency, a list, or every field on the form with react_on: :all, then derive its value with a format_using or options lambda that reads the current @record. Dependent forms like that are fiddly to wire and easy to break on the next Avo upgrade. This is a gem you add, not a piece of front-end plumbing you build and then maintain.