title: a-node.js TypeError: Cannot read property 'constructor' of undefined
body: <p>When I load my aframe project, I get this error, don't know how to trace that to whatever problem it indicates in my own code. Using <a href="https://aframe.io/releases/0.9.2/aframe.min.js" rel="nofollow noreferrer">https://aframe.io/releases/0.9.2/aframe.min.js</a></p>
  
  <p>Here's the whole trace:</p>
  
  <pre><code>core:a-node:error Failure loading node:   TypeError: Cannot read property 'constructor' of undefined
      at extendProperties (component.js:734)
      at i.callUpdateHandler (component.js:414)
      at i.updateProperties (component.js:298)
      at HTMLElement.updateComponent (a-entity.js:490)
      at HTMLElement.updateComponents (a-entity.js:456)
      at a-entity.js:249
      at a-node.js:127
  </code></pre>
  
  <p>How do I tell what node is the problem here? Any suggestions for tracing the problem are welcome. </p>
  
  <p>FWIW, this is pretty much the identical stack trace of the problem reported for v0.8.2 over here <a href="https://github.com/aframevr/aframe/issues/3920" rel="nofollow noreferrer">https://github.com/aframevr/aframe/issues/3920</a> . That was reported fixed, and I have no idea if it is significant, but maybe it will help suggest what's the matter to someone?  Since that bug appears to have had something to do with a camera, let me show my camera entity:</p>
  
  <pre><code>      &lt;a-entity id="mainCameraRig"&gt;
          &lt;a-entity camera
                    id="mainCamera"
                    wasd-controls
                    look-controls&gt;
          &lt;/a-entity&gt;
        &lt;/a-entity&gt;
  </code></pre>
  
  <p>Maybe something is wrong with that?</p>
  
  <p>Thanks.</p>