title: How to bind a checkbox to the inverse of a value?
body: <p>I have a case when I need to bind a checkbox and the visibility of another DOM element to the inverse of a boolean property of my viewModel:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;input type="checkbox" data-bind="checked: needsReview"&gt; Not Required 
  &lt;br&gt;
  &lt;div id="Some related text" data-bind="visible: needsReview"&gt; other stuff here &lt;/div&gt;
  </code></pre>
  
  <pre class="lang-javascript prettyprint-override"><code>var dataFromSever = { needsReview: true };
  
  var theModel = function (jsonData) {
      var self = this;
      ko.mapping.fromJS(jsonData, {}, self);
  }
  
  ko.applyBindings(new theModel(dataFromSever));
  </code></pre>
  
  <p>I have more than one property like this in my actual data model, so I do not want to make multiple <code>ko.computed()</code> fields.  I'd just like to bind to <code>"checked: !needsReview()"</code> or something equally simple to maintain.</p>