text: function fetchData() {
    var xhr = new XMLHttpRequest();
    xhr.responseType = 'json';
    xhr.open("post", "http://localhost:4000/graphql", true);
    xhr.setRequestHeader("Content-Type", "application/json");
    xhr.setRequestHeader("Accept", "application/json");
    xhr.onload = function () {
      console.log('data returned:', xhr.response);
    }
    xhr.send(JSON.stringify({query: "{ hello }"}));
  }
  
  var fetchBtn = document.getElementById('fetch-btn');
  fetchBtn.onclick = fetchData;
  