Write powerful wizards using page morphs

How?

• An empty state model is memoized in the controller (@book ||= Book.new(title: ...))
• A general purpose WizardReflex is used to step through the wizard and perist the model's state in the session
• A @current_step variable is in/decreased to display the current wizard pane.
• Validations are performed contextually, i.e. on: :step_1, etc.
• An allowlist approach is used to centrally sanitize resource classes and strong params in that reflex.

Caveat

In these examples, the amount of steps per wizard are hardcoded.

Variations

Enrich individual WizardReflexes with custom input processing logic:

class WizardReflex < ApplicationReflex
  def refresh
    additional_attributes, processed_resource_params = yield(resource_params) if block_given?

    session[:"new_#{resource_name.underscore}"] = resource_class.new(processed_resource_params || resource_params)
    session[:"new_#{resource_name.underscore}"].assign_attributes(**additional_attributes || {})

    # ...
  end
  
  # ...
end

class BookReflex < WizardReflex
  def refresh
    super do |params|
      [{isbn: '1234'}, params.except(...)]
    end
  end
end