How do you reference current_user with stimulus_reflex?

Trying to slightly build off the stimulus reflex dynamic forms checkbox lesson. I wanted to add the current_user id to the lastUpdateBy field when the checkbox is checked. I have not been able to get it to work though. Any thoughts on what I am doing wrong? If I hard code the value instead of current_user it works. I must just be referencing it wrong.

  def toggle
     todo = Todo.find(element.dataset[:id])
     todo.update(completed_at: (todo.completed_at? ? nil : Time.current), lastUpdatedBy: current_user)
  end

I didn't realize you had to delegate the current_user. per this: https://docs.stimulusreflex.com/authentication