---
title: Array.prototype.keys()
slug: Web/JavaScript/Reference/Global_Objects/Array/keys
tags:
  - Iteração
  - metodo
translation_of: Web/JavaScript/Reference/Global_Objects/Array/keys
---
<div>{{JSRef("Global_Objects", "Array")}}</div>

<h2 id="Summary" name="Summary">Sumário</h2>

<p>O método <code><strong>keys()</strong></code> retorna um novo <code><strong>Array Iterator</strong></code> que contém as chaves para cada <em>index</em> do array.</p>

<h2 id="Syntax" name="Syntax">Sintaxe</h2>

<pre class="syntaxbox"><code><var>arr</var>.keys()</code></pre>

<h2 id="Examples" name="Examples">Exemplos</h2>

<h3 id="Exemplo_uso_básico">Exemplo: uso básico</h3>

<pre class="brush: js">var arr = ["a", "b", "c"];
var iterator = arr.keys();

console.log(iterator.next()); // { value: 0, done: false }
console.log(iterator.next()); // { value: 1, done: false }
console.log(iterator.next()); // { value: 2, done: false }
console.log(iterator.next()); // { value: undefined, done: true }
</pre>

<h3 id="Exemplo_keys_iterator_não_ignora_lacunas">Exemplo: keys iterator não ignora lacunas</h3>

<pre class="brush: js">var arr = ["a", , "c"];
var sparseKeys = Object.keys(arr);
var denseKeys = [...arr.keys()];
console.log(sparseKeys); // [0, 2]
console.log(denseKeys);  // [0, 1, 2]
</pre>

<h2 id="Specifications" name="Specifications">Especificações</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Especificação</th>
   <th scope="col">Status</th>
   <th scope="col">Comentário</th>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-array.prototype.keys', 'Array.prototype.keys')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td>Definição inicial.</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility" name="Browser_compatibility">Compatibilidade de Browser</h2>

<div>{{CompatibilityTable}}</div>

<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>Suporte Básico</td>
   <td>{{CompatChrome("38")}}</td>
   <td>{{CompatGeckoDesktop("28")}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatOpera("25")}}</td>
   <td>{{CompatSafari("7.1")}}</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>Suporte Básico</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatGeckoMobile("28")}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>iOS 8</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also" name="See_also">Veja também</h2>

<ul>
 <li>{{jsxref("Array.prototype.values()")}}</li>
 <li>{{jsxref("Array.prototype.entries()")}}</li>
</ul>