title: mongoose calling .find inside a pre('save') hook
body: <p>Currently I'm trying to do the following:</p>
  
  <pre><code>const ItemSchema = mongoose.Schema({
   ...
   name : String
   ...
  });
  
  ItemSchema.pre('save', async function() {
    try{
       let count = await ItemSchema.find({name : item.name}).count().exec();
       ....
       return Promise.resolve();
    }catch(err){
       return Promise.reject(err)
    }
  });
  
  module.exports = mongoose.model('Item', ItemSchema);
  </code></pre>
  
  <p>But I Just get the following Error:</p>
  
  <blockquote>
    <p>TypeError: ItemSchema.find is not a function</p>
  </blockquote>
  
  <p>How do I call the .find() method inside my post('save') middleware ?
   (I know, that there is a unique property on Schmemas. I have to do it this way to suffix the name string if it already exists)</p>
  
  <p>mongoose version : 5.1.3
  nodejs version : 8.1.1
  system : ubuntu 16.04</p>