title: Delaying and iterating an object with rxjs
body: <p>I am trying to loop through the keys in an object and iterate over them after a set interval between one key to another. 
  I am trying to achieve this using the interval operator but I have been unsuccessful in doing so. </p>
  
  <pre><code>let obj = { 'a': [1,23,3], 'b': [12,23,2] };
   for(let key in data) {
        Observable.interval(5000).subscribe( () =&gt; {
           // perform operation with data[key]      
         });
    }
  </code></pre>
  
  <p>I don't see any delay between my loops and all i am getting is a sudden iteration which is not different from the normal loop beahvior. </p>