module Opal::Nodes::Helpers

def js_falsy(sexp)
  if sexp.type == :send
    mid = sexp.children[1]
    if mid == :block_given?
      scope.uses_block!
      return "#{scope.block_name} === nil"
    end
  end
  helper :falsy
  [fragment('$falsy('), expr(sexp), fragment(')')]
end