title: Using own properties in CKEditor 4 plugin (upgrade from version 3)
body: <p>I was using CKEditor 3 with the jQuery Adapter, wanted to update to version 4.3.1. But I stumbled upon a <code>Uncaught TypeError: Illegal constructor</code>.</p>
  
  <p>I found the row that creates this error, but I can't find a way to fix it. I got my own CKEditor plugins and set some meta-data to the plugins as well:</p>
  
  <p>MAIN.JS</p>
  
  <pre><code>objectWrapper.ckeditor(function(element){
       // Callback function code.
  }, {
      extraPlugins: 'companySave,companyImage',
      companySave: { ... },
      companyImage: { ... },
      companyMetaData: getMataData() //extra config field
  }
  </code></pre>
  
  <p>PLUGIN.JS (<em>companyImage</em>)</p>
  
  <pre><code>CKEDITOR.plugins.add( 'companyImage',
  {
  init: function( editor ) {
         ....
         editor.config.companyMetaData.doSomething() //using the extra config field
      }
  }
  </code></pre>
  
  <p>In CKEditor 3 I could do pass my own object to the plugins, but in version 4 it seems I cannot. Once I define my own config fields, I got that <code>Illegal constructor</code> error. </p>
  
  <p><strong>How can I pass my own object to plugins in CKEditor 4?</strong></p>
  
  <hr>
  
  <p>BTW </p>
  
  <pre><code>objectWrapper.ckeditor(function(element){
       // Callback function code.
  }, {
      extraPlugins: 'companySave,companyImage',
      companySave: { ... },
      companyImage: { 
         companyMetaData: getMataData() //extra config field
         ... 
      },
  }
  </code></pre>
  
  <p>gives met the same error.</p>
  
  <hr>
  
  <p><strong>EDIT</strong>
  Seems i can pass objects the way I described, but I can't pass jQuery objects.
  So <code>companyMetaData: $('body')</code> can't be used, but <code>companyMetaData: {}</code> is no problem.</p>