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.

“‘ruby 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.

“‘ruby 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