title: What does Winston callback actually mean?
body: <p>I am a beginner in Node js and was wondering if someone could help me out. </p>
  
  <p>Winston allows you to pass in a callback which is executed when all transports have been logged - could someone explain what this means as I am slightly lost in the context of callbacks and Winston?</p>
  
  <p>From <a href="https://www.npmjs.com/package/winston#events-and-callbacks-in-winston" rel="nofollow">https://www.npmjs.com/package/winston#events-and-callbacks-in-winston</a> I am shown an example which looks like this: </p>
  
  <pre><code>  logger.info('CHILL WINSTON!', { seriously: true }, function (err, level, msg, meta) {
      // [msg] and [meta] have now been logged at [level] to **every** transport. 
    });
  </code></pre>
  
  <p>Great... however I have several logger.info across my program, and was wondering what do I put into the callback? Also, do I need to do this for every <code>logger.info</code> - or can I put all the logs into one function? </p>
  
  <p>I was thinking to add all of the log call into an array, and then use <code>async.parallel</code> so they all get logged at the same time? Good or bad idea?</p>
  
  <p>The main aim is to log everything before my program continues with other tasks. </p>
  
  <p>Explanation of the code above in callback and winston context would be greatly appreciated! </p>