travel folder

/**
 * 遍历文件夹目录
 * @param  {[type]}   dir      [description]
 * @param  {Function} callback [description]
 * @return {[type]}            [description]
 */
function travel(dir, callback) {
    var fileList = [],
        folderList = [];
    var walk = function(filePath, fileList, folderList) {
        fs.readdirSync(filePath).forEach(function(file) {
            var pathname = path.join(filePath, file);
            var stats = fs.statSync(pathname);
            if (stats.isDirectory()) {
                walk(pathname, fileList, folderList);
                folderList.push(pathname);
            } else {
                fileList.push(pathname);
            }
        });
    }
    walk(dir, fileList, folderList);
    callback && callback(fileList, folderList);
}