code: function formatFileOutput(mappings, type) {
    var string = JSON.stringify(mappings, null, 2);
    if (type === '.js') {
      return 'module.exports=' + string;
    } else if (type === '.json') {
      return string;
    }
  }
docs: Formats class mapping output for writing to a file of specified type
  @param mappings Classname to renamed classname mappings repository
  @param type Output file type
  @return {string} Formatted output file contents