test.js

async function callEndpoint(serviceURL) {
  return new Promise(resolve => {
      $.ajax({
          type: "GET",
          url: serviceURL,
          contentType: 'application/json',
          success: successFunc,
          error: errorFunc
      });

      function successFunc(data, status) {
          resolve(data);
      }

      function errorFunc(data) {
          throw "Request failed. Please try again later.";
      }
  });
  }