title: Angular 6 - '"/node_modules/firebase/index"' has no exported member 'functions'
body: <blockquote>
    <p>ERROR in node_modules/angularfire2/firebase.app.module.d.ts(2,42):
    error TS2305: Module '"project/node_modules/firebase/index"' has no
    exported member 'functions'</p>
  </blockquote>
  
  <p>I'm using,</p>
  
  <pre><code>"@angular/cdk": "^6.2.1",
  "angularfire2": "^5.0.0-rc.10",
  "firebase": "^4.13.1"
  </code></pre>