title: asynchronous in node.js
body: <p>i want for pass array, and use data in array get data from redis to formation a new array. Then user the new array to work.</p>
  
  <p>i try user async.map, following code:</p>
  
  <pre><code>var sampleData = [{
      'name': 'name1',
      'age': 'age1'
  }, {
      'name': 'name2',
      'age': 'age2'
  }, {
      'name': 'name3',
      'age': 'age3'
  }];
  
  async.mapSeries(sampleData, function (data, callback) {
      return callback(null, data['name']);
  }, function (err, results) {
      console.log('results : ' + results); //results : name1,name2,name3  
  });
  </code></pre>
  
  <p>but the code have not callback when the loop finish</p>