title: How to fix Cannot find module 'rxjs-compat/Observable' error?
body: <p>I am creating an ionic app with Ionic 4 based on angular 6!
  To set the screen orientation installed the below plugin.</p>
  
  <pre><code>ionic cordova plugin add cordova-plugin-screen-orientation
  npm install --save @ionic-native/screen-orientation
  </code></pre>
  
  <p>And imported in required typescript! But when i run the project i got the error below.</p>
  
  <pre><code>ERROR in node_modules/@ionic-native/screen-orientation/index.d.ts(2,10): error TS2305: Module '"/Users/karthikcp/Documents/IONIC/myBake/node_modules/rxjs/Observable"' has no exported member 'Observable'.
  [ng] node_modules/rxjs/Observable.d.ts(1,15): error TS2307: Cannot find module 'rxjs-compat/Observable'.
  </code></pre>
  
  <p>Can anyone help me in fixing this error?</p>