title: angular 6 @angular/core/core"' has no exported member 'state'
body: <p>I migrated from angular 5.2 to 6.0.  When I issue the ng serve command, I get the following error:</p>
  
  <blockquote>
    <p>ERROR in src/app/mappy/mappy.component.ts(1,36): error TS2305: Module
    '"C:/NSE911/applicationDev/angular/alo/node_modules/@angular/core/core"'
    has no exported member 'state'.</p>
  </blockquote>
  
  <p>I am using: typescript: 2.7.2, angular cli: 6.0.1, Node: 8.11.2, OS: win32 x 64, angular: 6.0.0, rxjs-compat: "^6.1.0",</p>
  
  <p>I removed the node_modules directory and re-created it again (npm install). This did not work.<br>
  I will appreciate any ideas (I am kind of new using this technologies).
  Thanks for any help.</p>