CODEWITHSUNDEEP
ruby-on-rails-4activerecord
prasannaboga
prasannaboga

Reputation: 1014

Is there difference between using self.attribute and attribute in a model callbacks conditions?

is there any difference in callback adding conditions by using self.attribute_changed? or attribute_changed?

    class PlayEvent < ActiveRecord::Base
      ... 
      after_save :update_next_event_at!, if: 'self.event_at_changed?'
      after_save :update_next_event_at!, if: 'event_at_changed?'
      ...    

    end

which one is preferred to use?

Upvotes: 0

Views: 105

Answers (1)

SteveTurczyn
SteveTurczyn

Reputation: 36860

There's no difference, the self. isn't needed.

The only time you need self. is on assignment. If you have a model attribute comment and a method like...

def update_comment
  comment = "this is the new comment"
end

It may not be what you're expecting, as the assignment in this case creates a variable comment which is local to the method. Rubocop identifies this as a useless assignment as the comment variable is not subsequently used anywhere.

However...

def update_comment
  self.comment = "this is the new comment"
end

Will correctly change the record attribute.

Upvotes: 1

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