Better way to check 2 conditions based on 1 object

Question

I commonly need to use this kind of methods where I have to check if an object exists and if this object returns a specific value or a behavior. Is that a better way to write this code?

def set_current_theme
   if current_tenant && current_tenant.has_custom_domain?
     @theme = Theme.last || Theme.create
   end
end

At a first glance, I would just add one conditional: if current_tenant.has_custom_domain? and that should be enough. But the result is generally that there is no such method (in this case has_custom_domain?) for nil class.

score 2 · Answer 1 · answered Jun 24 '21 at 03:38

2

Shorter (and i think better) way is to use &. (it's shorthand for try!) like this.

if current_tenant&.has_custom_domain?
  @theme = Theme.last || Theme.create
end

What does &. (ampersand dot) mean in Ruby?

answered Jun 24 '21 at 03:38

blackbiron

809
10
17

Thanks a lot! This was very useful. I had never really understood the use of the ampersand. – Gustavo Borges Jun 25 '21 at 13:51

score 1 · Accepted Answer · answered Jun 24 '21 at 15:14

1

I would suggest early return (so called guard clause) instead of :if statement, because you don't have :else clause:

def set_current_theme
  return unless current_tenant&.has_custom_domain?

  @theme = Theme.last || Theme.create
end

answered Jun 24 '21 at 15:14

Ruslan Valeev

1,529
13
24

even better. i forgot about guard clause. – blackbiron Jun 24 '21 at 23:23
great! I didn't know that one! – Gustavo Borges Jun 25 '21 at 13:51

Better way to check 2 conditions based on 1 object

2 Answers2