title: Making custom events on webworkers
body: <p>I made a webworker and tried to add a custom event called progress as follows:</p>
  
  <pre><code>self.updateProgress = function(no){
      let event = new CustomEvent(
          'progress',
          {
              detail : {
                  description: "event from webworker to update progress",
                  timeofevent: new Date(),
                  eventcode: 15
              },
              bubbles: true,
              cancelable: false,
              data : no
          });
          self.console.log(self.dispatchEvent(event));
      };
  </code></pre>
  
  <p>On the parent JavaScript:</p>
  
  <pre><code>scope.worker.addEventListener('progress', (e) =&gt; { //cannot add custom events to worker yet
      scope.progress = e.data;
  });
  </code></pre>
  
  <p>The problem is that the event is never triggered, and from what I have read, it seems that message and error are the only events that are attached to the worker object. Is it impossible to add custom events?</p>