title: TypeScript for ... of with index / key?
body: <p>As described <a href="https://basarat.gitbooks.io/typescript/content/docs/for...of.html">here</a> TypeScript introduces a foreach loop:</p>
  
  <pre><code>var someArray = [9, 2, 5];
  for (var item of someArray) {
      console.log(item); // 9,2,5
  }
  </code></pre>
  
  <p>But isn't there any index/key? I would expect something like:</p>
  
  <pre><code>for (var item, key of someArray) { ... }
  </code></pre>