title: Node.js concat array after async.concat()
body: <p>I have an array, I need to recompile with the use of some edits. I do it with the help of <a href="https://github.com/caolan/async#concat" rel="nofollow"><code>async.concat()</code></a>, but something is not working.
  Tell me, where is the mistake?</p>
  
  <pre><code>async.concat(dialogs, function(dialog, callback) {
      if (dialog['viewer']['user_profile_image'] != null) {
          fs.exists(IM.pathToUserImage + dialog['viewer']['user_profile_image'].replace('%s', ''), function(exits) {
              if (exits) {
                  dialog['viewer']['user_profile_image'] = dialog['viewer']['user_profile_image'].replace('%s', '');
              }
              callback(dialog);
          });
      }
  }, function() {
      console.log(arguments);
  });
  </code></pre>
  
  <p>In my opinion, everything is logical. callback is invoked immediately after the first iteration. But how can I send the data after the completion of processing the entire array?</p>
  
  <p><strong>Thank you!</strong></p>