title: Mongoose - Query nested objects
body: <p>Let consider this collection of posts. Each post has an array of comments and each comments has an array on string, with the key 'likes', which indicates the users who like the comment.</p>
  
  <pre><code>{
  _id: 000
  created_at:
  user_id:
  comments: [{
         _id: 111
         created_at:
         likes: [user_id1 , user_id2 , user_id3]
         },
         {
         _id: 222
         created_at:
         likes: [user_id1]
         },]
  }
  </code></pre>
  
  <p>How can I check, with mongoose, if a user has liked a comment with a given id?</p>