title: Resolve a promise once in a racing time
body: <p>Here is a Promise:</p>
  
  <p><code>var getVersion = new Promise(function(resolve){
      getVersionAsyn(resolve);
  });
  </code>
  <del>Then a lot of http requests depend on that 'version' and the requests send in the same time.</del></p>
  
  <p>When page initial, a lot of http requests will send to server and the request are depend on 'version'.</p>
  
  <p>How to prevent <code>getVersion</code> promise run multiple times?</p>
  
  <hr>
  
  <p>All right. I down vote myself. Such a idiot question.</p>