class Opal::Nodes::ConstNode

def magical_data_const?

DATA const should be resolved to a regular ::DATA constant
2. When current file doesn't have __END__ section
DATA const should be resolved to the string located after __END__
1. When current file contains __END__ in the end of the file
that should be processed in a different way:
Ruby has a magical const DATA 
def magical_data_const?
  const_scope.nil? && name == :DATA && compiler.eof_content
end