title: Pass more values to subscribe function of an observables
body: <p>I would like to convert and replace all words in an array using a an object's method which returns an observable. The problem is that since the result is asynchronous, the value of result is overwritten incorrectly at the wrong index. If I had a synchronous function, I could have just simply call the function in a for loop. What should I do in this case?</p>
  
  <pre><code> for(let word in this.words){
          var i = Object.keys(this.words).indexOf(word);
  
          this.convertor.get(this.words[i].value).subscribe( (result) =&gt; {
              this.words[i].value = result; //The value of i is incorrect
          });
      }
  </code></pre>