title: How to get index from array - graphql?
body: <p>I need to know the array item index when it's not returned by downstream response. Suppose my schema looks like</p>
  
  <pre><code>schema:
  type Cart {
     items: [Item]
  }
  
  type Item {
     name: String
     index: Int
  }
  </code></pre>
  
  <p>data comes:</p>
  
  <pre><code> {items: [{name: apple}, {name: mango},]}
  </code></pre>
  
  <p>resolvers look like:</p>
  
  <pre><code>Cart: {
     items(obj, context, info) {
       return obj;
     }
  }
  
  Item: {
     name(obj, context, info) {
       return obj.name;
     }
     index(obj, context, info) {
       // how to get it?
     }
  }
  </code></pre>
  
  <p>How to get <code>ith index</code> in items array?</p>