Module: Roadie::Rails::Utils

Defined in:
lib/roadie/rails/utils.rb

Class Method Summary collapse

Class Method Details

.combine_callable(first, second) ⇒ Object

Return a callable that will call both inputs. If either is nil, then just return the other.

The result from the second one will be the result of the combined callable.

combine_callable(-> { 1 }, -> { 2 }).call # => 2
combine_callable(-> { 1 }, nil).call # => 1
combine_callable(nil, nil).nil? # => true



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# File 'lib/roadie/rails/utils.rb', line 27

def combine_callable(first, second)
  combine_nilable(first, second) do |a, b|
    lambda do |*args|
      a.call(*args)
      b.call(*args)
    end
  end
end

.combine_hash(first, second) ⇒ Object

Combine two hashes, or return the non-nil hash if either is nil. Returns nil if both are nil.



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# File 'lib/roadie/rails/utils.rb', line 10

def combine_hash(first, second)
  combine_nilable(first, second) do |a, b|
    a.merge(b)
  end
end

.combine_nilable(first, second) ⇒ Object

Discard the nil value. If neither is nil, then yield both and return the result from the block.

combine_nilable(nil, 5) { |a, b| a+b } # => 5
combine_nilable(7, nil) { |a, b| a+b } # => 7
combine_nilable(nil, nil) { |a, b| a+b } # => nil
combine_nilable(7, 5) { |a, b| a+b } # => 12



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# File 'lib/roadie/rails/utils.rb', line 53

def combine_nilable(first, second)
  if first && second
    yield first, second
  else
    first || second
  end
end

.combine_providers(first, second) ⇒ Object

Combine two Provider ducks into a ProviderList. If either is nil, pick the non-nil value instead.



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# File 'lib/roadie/rails/utils.rb', line 38

def combine_providers(first, second)
  combine_nilable(first, second) do |a, b|
    ProviderList.new(a.to_a + Array.wrap(b))
  end
end