title: Pass TWIG Objects to Javascript (json_encode result is empty)
body: <p>I have a collection of items passed from my controller to my twig template called qualifications. I then loop through each object in the collection and print it to a row in the table. Every respective row has an "Edit" button, which should pass that object's values to a javascript function. Here is my code:</p>
  
  <pre><code>{%for qualification in qualifications%} 
      &lt;tr id="qualification_{{qualification.id}}"&gt;
          &lt;td&gt;{{qualification.name}}&lt;/td&gt;
          &lt;td&gt;{{qualification.saqaId}}&lt;/td&gt;
          &lt;td&gt;{{qualification.qualificationType}}&lt;/td&gt;
          &lt;td&gt;{%if (qualification.course is null) %} - {%else%} {{qualification.course.name}} {%endif%}&lt;/td&gt;
          &lt;td&gt;0&lt;/td&gt;
          &lt;td&gt;&lt;a class="button btn-primary btn-xs" onclick="setForm({{qualification|json_encode(constant('JSON_PRETTY_PRINT'))}});"&gt;Edit&lt;/a&gt;&lt;/td&gt;
      &lt;/tr&gt;
  {%endfor%}
  </code></pre>
  
  <p>I am getting the information in the table row as expected, but when looking at the HTML on the Edit button I just see <code>onclick="setForm({});"</code>. I have tried with and without the raw, I have also tried <code>{{qualification|json_encode(constant('JSON_PRETTY_PRINT'))}}</code> but all return blank.</p>
  
  <p>On a similar, but not related note. I have been having other issues with TWIG as well. <code>{{dump()}}</code> just loads a while and then gives a blank page with an unspecified 500 error.  have tried activating the twig debug in services.xml and config.yml with what documentation I could find, but to no avail. This, however is not my primary concern, my primary concern is json_encode returning an empty result.</p>
  
  <p>And help or advice on this would be greatly appreciated as I have run into a wall.</p>