code: function format(source, style) {
  	if (style.insert_final_newline !== undefined) {
  		const has = hasTrailingNewLine(source);
  		if (style.insert_final_newline && !has) {
  			source += '\n';
  		} else if (!style.insert_final_newline && has) {
  			source = source.replace(TRAILING_NEW_LINE_REGEXP, '');
  		}
  	}
  
  	return source;
  }
docs: Reformat text according to a given EditorCofnig style.
  
  Suports: insert_final_newline
  
  @param {string} source
  @param {EditorConfigStyle} style
  @return {string}