title: Iron-ajax Data binding
body: <p>How to data bind in the new Polymer v1.0?</p>
  
  <p>I saw an answer in <a href="https://stackoverflow.com/questions/30295236/polymer-iron-ajax-how-to-bind-data-from-input-element-to-iron-ajaxs-body-attr/30322559#">polymer iron-ajax : How to Bind data from input element to iron-ajax&#39;s body attribute</a></p>
  
  <p>But it did not help me and Here is my code</p>
  
  <pre><code>&lt;dom-element id="test-app&gt; 
  &lt;template&gt;
  ...
  &lt;iron-ajax
  auto
  url="https://www.googleapis.com/youtube/v3/search"
  params="{{ajaxParams}}"
  handleAs="json" lastResponse="{{response}}"
  method='GET'&gt;
  &lt;/iron-ajax&gt;
  &lt;/template&gt;
  &lt;/dom-module&gt;
  </code></pre>
  
  <p>Script</p>
  
  <pre><code>Polymer({
          is:"Test-app",
  
          properties: {
              qry: {
                  type: String,
                  value: 'Cat'
              },
              key1: {
                  type: String,
                  value: 'myapikey'
              },
              part1: {
                  type: String,
                  value: 'snippet'
              },
              maxResults1: {
                  type: Number,
                  value: 10
              },
              ajaxParams: {
                  type: String,
                  computed: 'processParams(part1, qry, maxResults1, key1)'
              }
          },
          processParams: function(part1, qry, maxResults1, key1){
              var param = JSON.stringify({part: part1, q:qry, maxResults: maxResults1, key:key1});
              console.log(param);
              return param;
          }
      });
  &lt;/script&gt;
  </code></pre>
  
  <p>I get the correct log in console as a JSON string, but when this value is being returned, the value is taken literally (same problem as told in the link provided above) and not as its value.</p>
  
  <p>I get an error in console as bad request code 400. Any help is highly appreciated.</p>