title: Validating multiple mongoose document and updating
body: <p>We have a mongoose model <code>Offer</code> and it has a field called <code>activatedDate</code> and <code>expirationDate</code>.</p>
  
  <p>And in pre validate hook, I have my validation logic that throw error if <code>expirationDate</code> is less than <code>activatedDate</code>. (This is just an example, we have multiple fields which are being validated based on the record value of other field)</p>
  
  <p>By doing this, I can validate and insert/update a single <code>Offer</code> document.
  So far so good..</p>
  
  <p>Now, we want to implement a new feature to multi-edit <code>Offer</code> model. So that our users don't have to update same field with same value one by one..</p>
  
  <p>Keep in mind that we are expecting more than 10k Offers in system and theoretically. User can update all at once using this feature..</p>
  
  <p>Is there a best way to update multiple mongoose document only after my validation is successful?</p>
  
  <p>We can't do first lookup and then validate it one by one. It will take lot of time to do that.</p>
  
  <p>Is there a optimal way to achieve this? 
  It's OK if I have to change the way i am validating my model. I am open to any suggestions..</p>