title: How to make countdown timer with RxJS Observables?
body: <p>I'm struggling to create a countdown timer using Observables, the examples at <a href="http://reactivex.io/documentation/operators/timer.html" rel="noreferrer">http://reactivex.io/documentation/operators/timer.html</a> do not seem to work.  In this specific example the error related to timerInterval not being a function of the Observable returned from timer. </p>
  
  <p>I have also been experimenting with other approaches and the best I've come up with is:</p>
  
  <pre><code>Observable.interval(1000).take(10).subscribe(x =&gt; console.log(x));
  </code></pre>
  
  <p>The problem here is it counts up from 0 to 10 and I want a countdown timer e.g. 10,9,8...0.</p>
  
  <p>I've also tried this but the <code>timer</code> does not exist for type Observable</p>
  
  <pre><code>Observable.range(10, 0).timer(1000).subscribe(x =&gt; console.log(x));
  </code></pre>
  
  <p>As well as, which produces no output at all.</p>
  
  <pre><code>Observable.range(10, 0).debounceTime(1000).subscribe(x =&gt; console.log(x));
  </code></pre>
  
  <blockquote>
    <p>To clarify I need help with ReactiveX's RxJS implementation, not the MircoSoft version.</p>
  </blockquote>