title: Compare value of month and timestamp
body: <p>I have created a mongodb which looks like:</p>
  <pre><code>{
      &quot;_id&quot; : ObjectId(&quot;5ece47aa6510a611b47aac5a&quot;),
      &quot;array&quot; : [ 
          {
              &quot;_id&quot; : ObjectId(&quot;5ece47aa6510a611b47aac6e&quot;),
              &quot;timestamp&quot; : &quot;1470420945250&quot;,
              &quot;type&quot; : &quot;f1&quot;
          }, 
          {
             &quot;_id&quot; : ObjectId(&quot;5ece47aa6510a611b47a8895&quot;),
             &quot;timestamp&quot; : &quot;1470420945250&quot;
             &quot;type&quot; : &quot;f2&quot;
          },
          {..},
          
  </code></pre>
  <p>{..}
  ]
  Now i am trying to make a query to match the timestamps above with a specific month. Something like this:</p>
  <pre><code>const types = await Location.aggregate([ 
      {    
            $match:{
              &quot;array.timestamp&quot; : 09
             }
       }
  ])
  </code></pre>
  <p>How can i compare the value of the timestamp with the month Semptember for example?</p>