title: Why is there no forEach method on Object in ECMAScript 5?
body: <p>ECMAScript 5's <code>array.forEach(callback[, thisArg])</code> is very convenient to iterate on an array and has many advantage over the syntax with a for:</p>
  
  <ul>
  <li>It's more concise. </li>
  <li>It doesn't create variables that we need only for the purpose of iterating. </li>
  <li>It's creates a visibility scope for the local variables of the loop.</li>
  <li>It boosts the performance.</li>
  </ul>
  
  <p><strong>Is there a reason why there is no <code>object.forEach</code> to replace <code>for(var key in object)</code> ?</strong></p>
  
  <p>Of course, we could use a JavaScript implementation, like _.each or $.each but those are performance killers.</p>