class Opal::Nodes::TopNode

def opening
  async_prefix = "async " if await_encountered
  if compiler.requirable?
    unshift "#{async_prefix}function(Opal) {"
  elsif compiler.eval?
    unshift "(#{async_prefix}function(Opal, self) {"
  else
    unshift "Opal.queue(#{async_prefix}function(Opal) {"
  end
end