azback5 said over 3 years ago on User Notifications :
Ok, I think I get the logic, but not sure if I've gotten the syntax correct. 

  def create

      @comment = @commentable.comments.new(comment_params)
      @comment.user = @current_user
      if @comment.save
        CommentNotifier.call(@comment)
        if @comment = @commentable
        else 
          nil
        end
        respond_to do |format|
          format.html { redirect_to @commentable }
          format.js # create.js.erb
        end

Basically, if the commentable object is a comment, then the user of that commentable comment SHOULD receive a notification. 
Else, if commentable is a not a comment (i.e. a BlogPost) they shouldn't!

How would you include the guard clause return unless current_user == comment.user in there as well?

Thanks David!