javascript: indesign filter files regexp

gistfile1

function filter_files (param_files, file_name_part) {	
	var all_files 		= param_files || [];
	var selected_files	= [];
	var my_reg			= new RegExp(file_name_part);
	if(all_files.length === 0 ) {return [];}	
	for (var i = 0, len = all_files.length; i < len; i++) {
		if(my_reg.test(all_files[i].name)) {
			selected_files.push(all_files[i]);
		};
	};
	return selected_files;
};