title: Why is it important to use Discriminator when implementing Mongoose?
body: <p>I've read mongoose documentation but still didn't get it, when i create a mongoose schema I can create fields that I might not use like</p>
  
  <pre><code>var productSchema = new Schema({
      name: {
          type: String,
          required: true
      },
      fruit: [{
         color: String,
         season: String
     }],
     book: [{
         pages:String,
         author: String
    }]
  ]);
  </code></pre>
  
  <p>Then if i miss book object, it won't be written on product model so why should I use discriminators IF I'm going to get same result can some1 explains please.</p>