title: Getting "is not a function " errors with RxJS
body: <p>Seemingly out of the blue I am getting errors with RxJS.</p>
  
  <p>My project is Angular, Typescript and I use RxJS as part of NGRX redux.</p>
  
  <p>My code <em>seemed</em> to work absolutely fine with just this as an import:</p>
  
  <p><code>import { Observable } from 'rxjs/Observable'</code></p>
  
  <p>Then, from nowhere I started getting errors like this...</p>
  
  <p><code>Uncaught (in promise): TypeError: this.appStateStore.withLatestFrom is not a function</code>
  <code>Uncaught (in promise): TypeError: this.appStateStore.take is not a function</code></p>
  
  <p>I was able to solve the error about <code>withLatestFrom</code> by adding an import of <code>import 'rxjs/add/operator/withLatestFrom';</code> but then the error moved to complaining about <code>.take</code>. </p>
  
  <p>I'm guessing I have an import wrong somewhere as I understand with RxJS you need to import the bits that you need. However I've reviewed my source control changes and I can't see that any changes (e.g. node module version, import statements) that would cause this to just start happening.</p>
  
  <p>What I am doing wrong?</p>