Making an iron-ajax call

<link rel="import" href="https://cdn.rawgit.com/Download/polymer-cdn/master/lib/polymer/polymer.html" />
<link rel="import" href="https://cdn.rawgit.com/Download/polymer-cdn/master/lib/iron-ajax/iron-ajax.html" />

<dom-module id="ajax-element">

  <template>
    <iron-ajax 
    auto
    url="https://jsonplaceholder.typicode.com/posts/1"
    handle-as="json"
    last-response="{{response}}"
    id="xhr"></iron-ajax>
  </template>

  <script>
    let url = "https://jsonplaceholder.typicode.com/posts/";
    Polymer({
      is: "ajax-element",
      properties: {
        response: {
          type: String
        }
      }
    });
  </script>

</dom-module>