Flatten Array Recursively

flatten.rb

def flatten(array)
  if array.empty?
    array
  else
    element = array.pop
    element.kind_of?(Array) ? flatten(array) + flatten(element) : flatten(array) << element
  end
end


flatten(["bananas", [1,2,3], ["apple", "cheese", [100, 20]], [true], 'C']) # ["bananas", 1, 2, 3, "apple", "cheese", 100, 20, true, "C"]
flatten([['A','B'],'C']) # ["A", "B", "C"]