Revision 707029 of Iterator

<div>
 {{jsSidebar("Objects")}}</div>
<div class="warning">
 <strong>Non-standard.</strong> The <code><strong>Iterator</strong></code> function is a SpiderMonkey-specific feature, and will be removed at some point. For future-facing usages, consider using <a href="/en-US/docs/Web/JavaScript/Reference/Statements/for...of" title="/en-US/docs/Web/JavaScript/Reference/Statements/for...of">for..of</a> loops and the <a href="/en-US/docs/Web/JavaScript/Guide/The_Iterator_protocol">iterator protocol</a>.</div>
<h2 id="Summary">Summary</h2>
<p>The <code><strong>Iterator</strong></code> function returns an object which implements legacy iterator protocol and iterates over enumerable properties of an object.</p>
<h2 id="Syntax" name="Syntax">Syntax</h2>
<pre class="syntaxbox">
Iterator(<var>object</var>)</pre>
<h3 id="Parameters" name="Parameters">Parameters</h3>
<dl>
 <dt>
  <code>object</code></dt>
 <dd>
  Object to iterate over properties.</dd>
</dl>
<h2 id="Description">Description</h2>
<p>An overview of the usage is available on the <a href="/en-US/docs/JavaScript/Guide/Iterators_and_Generators" title="/en-US/docs/JavaScript/Guide/Iterators_and_Generators">Iterators and Generators</a> page.</p>
<h2 id="Properties">Properties</h2>
<h2 id="Methods">Methods</h2>
<dl>
 <dt>
  <code><strong>Iterator.prototype.next</strong></code></dt>
 <dd>
  Returns next item in the <code>[property_name, property_value]</code> format. It throws <code><a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/StopIteration">StopIteration</a></code> if there are no more items.</dd>
</dl>
<h2 id="Examples">Examples</h2>
<h3 id="Iterating_over_properties_of_an_object">Iterating over properties of an object</h3>
<pre class="brush: js">
var a = {
  x: 10,
  y: 20,
};
var iter = Iterator(a);
console.log(iter.next()); // ["x", 10]
console.log(iter.next()); // ["y", 20]
console.log(iter.next()); // throws StopIteration
</pre>
<h3 id="Iterate_over_properties_of_an_object_with_legacy_destructuring_for-in_statement">Iterate over properties of an object with legacy destructuring <code>for-in</code> statement</h3>
<pre class="brush: js">
var a = {
  x: 10,
  y: 20,
};

for (var [name, value] in Iterator(a)) {
  console.log(name, value);   // x 10
                              // y 20
}
</pre>
<h2>Specifications</h2>
<p>Non-standard. Not part of any current standards document.</p>
<h2 id="Browser_compatibility">Browser compatibility</h2>
<p>{{CompatibilityTable}}</p>
<div id="compat-desktop">
 <table class="compat-table">
  <tbody>
   <tr>
    <th>Feature</th>
    <th>Chrome</th>
    <th>Firefox (Gecko)</th>
    <th>Internet Explorer</th>
    <th>Opera</th>
    <th>Safari</th>
   </tr>
   <tr>
    <td>Basic support</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatNo}}</td>
   </tr>
  </tbody>
 </table>
</div>
<div id="compat-mobile">
 <table class="compat-table">
  <tbody>
   <tr>
    <th>Feature</th>
    <th>Android</th>
    <th>Chrome for Android</th>
    <th>Firefox Mobile (Gecko)</th>
    <th>IE Mobile</th>
    <th>Opera Mobile</th>
    <th>Safari Mobile</th>
   </tr>
   <tr>
    <td>Basic support</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatVersionUnknown}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatNo}}</td>
    <td>{{CompatNo}}</td>
   </tr>
  </tbody>
 </table>
</div>
<h2 id="See_also">See also</h2>
<ul>
 <li><a href="/en-US/docs/JavaScript/Guide/Iterators_and_Generators" title="/en-US/docs/JavaScript/Guide/Iterators_and_Generators">Iterators and Generators</a></li>
 <li><code><a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/StopIteration">StopIteration</a></code></li>
</ul>