Rails 5 introduces ArrayInquirer that wraps an array object and provides friendlier methods to check for the presence of elements that can be either a string or a symbol.
pets = ActiveSupport::ArrayInquirer.new([:cat, :dog, 'rabbit'])
> pets.cat?
#=> true
> pets.rabbit?
#=> true
> pets.elephant?
#=> false
Array Inquirer also has any? method to check for the presence of any of the passed arguments as elements in the array.
pets = ActiveSupport::ArrayInquirer.new([:cat, :dog, 'rabbit'])
> pets.any?(:cat, :dog)
#=> true
> pets.any?('cat', 'dog')
#=> true
> pets.any?(:rabbit, 'elephant')
#=> true
> pets.any?('elephant', :tiger)
#=> false
Since ArrayInquirer class inherits from Array class, it's any? method performs same as any? method of Array class when no arguments are passed.
pets = ActiveSupport::ArrayInquirer.new([:cat, :dog, 'rabbit'])
> pets.any?
#=> true
> pets.any? { |pet| pet.to_s == 'dog' }
#=> true
Use inquiry method on array to fetch Array Inquirer version
For any given array we can have its Array Inquirer version by calling inquiry method on it.
pets = [:cat, :dog, 'rabbit'].inquiry
> pets.cat?
#=> true
> pets.rabbit?
#=> true
> pets.elephant?
#=> false
Usage of Array Inquirer in Rails code
Rails 5 makes use of Array Inquirer and provides a better way of checking for the presence of given variant. Before Rails 5 code looked like this.
request.variant = :phone
> request.variant
#=> [:phone]
> request.variant.include?(:phone)
#=> true
> request.variant.include?('phone')
#=> false
Corresponding Rails 5 version is below.
request.variant = :phone
> request.variant.phone?
#=> true
> request.variant.tablet?
#=> false
Posted by Alexander M to Ruby and RoR knowledge base (2016-06-15 14:26)