title: How to detect if PWA is already installed on IOS
body: <p>I have PWA angular application and I want to show user popup that he/she can add application on homescreen.</p>
  <p>I don't want this notification to be shown in PWA but only IOS Safari, so I use this check:</p>
  <pre><code>const isInStandaloneMode = () =&gt; ('standalone' in window.navigator) &amp;&amp; (window.navigator.standalone);
  </code></pre>
  <p>I also don't want to show this popup on IOS Safari when user already installed PWA, is there any chance to check whether or not PWA is already installed?</p>