title: getDisplayMedia is not specified in TypeScript 3.8
body: <p>I'm writing a .Net Core/Angular 8 app in Visual Studio.</p>
  <p>Within the Angular (ClientApp) part of the application, my node_modules contains TypeScript 3.5.3, which has the following defined in <code>lib.dom.d.ts</code>:</p>
  <pre><code>interface NavigatorUserMedia {
      readonly mediaDevices: MediaDevices;
      getDisplayMedia(constraints: MediaStreamConstraints): Promise&lt;MediaStream&gt;;
      getUserMedia(constraints: MediaStreamConstraints, successCallback: NavigatorUserMediaSuccessCallback, errorCallback: NavigatorUserMediaErrorCallback): void;
  }
  </code></pre>
  <p>So I should be able to call <code>navigator.getDisplayMedia(...)</code>, however when I try this I get a redline under it saying <code>getDisplayMedia</code> is not a function of navigator.</p>
  <p>Thus I clicked &quot;Go To Definition&quot; of <code>navigator</code> and it took me to the TypeScript defined in <code>C:\Program Files (x86)\Microsoft SDKs\TypeScript</code>, which is apparently TypeScript 3.8.3. This also seems to be the &quot;TypeScript Version&quot; defined under Project Properties &gt; TypeScript Build. Looking in the <code>lib.dom.d.ts</code> file, it appears there is absolutely no getDisplayMedia function whatsoever.</p>
  <p>I attempted to use NuGet to download TypeScript 3.5.3, which correctly changed the TypeScript version under Project Properties &gt; TypeScript Build, and removed the redline which allowed me to properly build the project. However, when attempting to call the function, an error outputs to the browser console saying that getDisplayMedia is not a function of navigator...</p>
  <p>What the hell is going on?</p>
  <p>Note: I know that <a href="https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices/getDisplayMedia" rel="nofollow noreferrer">getDisplayMedia</a> should be called from MediaDevices. However in <code>lib.dom.d.ts</code> for both TypeScript 3.5.3 and 3.8.3, MediaDevices does not contain getDisplayMedia.</p>