Synchronous nodejs directory loop

index.js

var glob = require("glob");
var fs = require("fs");

// async map file contents
		var async = function async(arg, callback) {
		  	fs.readFile(arg, 'utf8', function (err, data) {
			    if (err) throw err;
				callback(arg, data);
			});
		};
// loop directory
		glob("test/**/*.js", function (er, files) {
				files.forEach(function(item) {
					async(item, function(filePath, data){
					    
					    _this[ collection ].push(
							{
								path : filePath,
								contents : data
							}
						);

					    if( _this[ collection ].length == files.length ) {
					     // finished to read all files. Then invoke callback
					      _cb();
					    }
					  })
				});
		});