title: arrayFilters in mongodb
body: <p>I have the following schema.</p>
  
  <pre><code>{
     posts: [
            {
               _id: '5ayuunbdsyuuuyut778'
               replies: [{
                   _id: "67hfudj7e9whduu888",
                   text: "something"
               }]
            }
        ]
  }
  </code></pre>
  
  <p>I want to update the text in particular reply.
  I am using mongoose.</p>
  
  <p>I have written the query as follows</p>
  
  <pre><code>Post.findOneAndUpdate(
     {'posts.replies._id': _id}, 
     {$set: {'posts.$[post].replies.$[reply].text': "something1"}},
     { arrayFilters: [{'post._id': postId}, { 'reply._id': _id }]}
   )
  </code></pre>
  
  <p>This query is not updating the document.</p>
  
  <p>Am I missing something? Do I need to cast ids using ObjectId</p>