title: How to get $match result in single document and not in array?
body: <p>I have the a topic collection like so</p>
  
  <pre><code> {
      "_id": "1",
      "topic_name": "Animation",
  },
   {
      "_id": "2",
      "topic_name": "Animation"
  }
  </code></pre>
  
  <p>and when I use </p>
  
  <pre><code>    db.topic.aggregate([
    {
      $match: { _id: 1 }
    }
  </code></pre>
  
  <p>I get the result in array</p>
  
  <pre><code>[
  {
      "_id": "1",
      "topic_name": "Animation"
  }
  ]
  </code></pre>
  
  <p>My question is: is it possible to get the result in single document and not in array with $match? I don't want to use findOne method because I still need to create one more pipeline with aggregate. My expected result would be</p>
  
  <pre><code>{
      "_id": "1",
      "topic_name": "Animation"
  }
  </code></pre>
  
  <p>Thank you all for helping me!</p>