title: GraphQL and form validation errors
body: <p>Let's say you have a form which posts data to API server. The API server validates the input and returns JSON object. If the input is invalid an error objects like the one below is returned.</p>
  
  <pre><code>{errors: {field1: "is required"}}
  </code></pre>
  
  <p>How do we handle and serve these kind of errors when using GraphQL? How and where should data validation be implemented (should that be part of GraphQL or should it be inside each resolve function)?</p>