title: TypeScript error: Property 'app' does not exist on type 'Navigator'
body: <p>I keep getting this error:</p>
  
  <pre><code>&gt; TypeScript error: Property 'app' does not exist on type 'Navigator'
  </code></pre>
  
  <p>while using this code:</p>
  
  <pre><code>navigator.app.exitApp();
  </code></pre>
  
  <p>I have the following plugins:</p>
  
  <pre><code>&gt; &lt;plugin name="cordova-plugin-device" spec="~1.1.2"/&gt;
  &gt; &lt;plugin name="cordova-plugin-console" spec="~1.0.3"/&gt;
  &gt; &lt;plugin name="cordova-plugin-whitelist" spec="~1.2.2"/&gt;
  &gt; &lt;plugin name="cordova-plugin-splashscreen" spec="~3.2.2"/&gt;
  &gt; &lt;plugin name="cordova-plugin-statusbar" spec="~2.1.3"/&gt;
  &gt; &lt;plugin name="ionic-plugin-keyboard" spec="~2.2.1"/&gt;
  </code></pre>
  
  <p>What might be wrong with my code?</p>