title: Unable to query from non-Apollo GraphQL server from Apollo client
body: <p>I tried to make a request using Apollo Client into non-Apollo GraphQL server as below:</p>
  
  <pre><code>import ApolloClient, { createNetworkInterface } from 'apollo-client';
  
  // Register gql globally
  import { registerGqlTag } from 'apollo-client/gql';
  registerGqlTag();
  
  const networkInterface = createNetworkInterface(' http://localhost:8080/graphql', {
    headers: {
    'Content-type': "application/json"
    }
  });
  
  var client = new ApolloClient({
    networkInterface
  });
  
  client.query({
    query: gql`
      query getTodo($todoId: Int!) {
        node(id: $todoId) {
          ... on Todo {
            id
            text
          }
        }
      }
    `,
    variables: {
      todoId: "todo:100000",
    },
    forceFetch: false,
  }).then((graphQLResult) =&gt; {
    var errors  = graphQLResult.errors;
    var data = graphQLResult.data;
  
    if (data) {
      console.log('got data', data);
    }
  
    if (errors) {
      console.log('got some GraphQL execution errors', errors);
    }
  }).catch((error) =&gt; {
    console.log('there was an error sending the query', error);
  });
  </code></pre>
  
  <p>However I keep getting an error while running the code:
  <code>there was an error sending the query [ReferenceError: fetch is not defined]</code></p>
  
  <p>I try to search the issue related to that, however the documentation doesn't really helpful.  </p>
  
  <p>Thanks before.</p>