---
title: Symbol.hasInstance
slug: Web/JavaScript/Reference/Global_Objects/Symbol/hasInstance
tags:
  - Propriedade
  - Referencia
translation_of: Web/JavaScript/Reference/Global_Objects/Symbol/hasInstance
---
<div>{{JSRef}}</div>

<p>O symbol bem-conhecido <strong><code>Symbol.hasInstance</code></strong> é usado para determinar se um objeto construtor reconhece um objeto como de sua instância. O comportamento do operador {{jsxref("Operators/instanceof", "instanceof")}} pode ser customizado por este symbol.</p>

<div>{{js_property_attributes(0,0,0)}}</div>

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

<p>Você pode implementar o comportamento customizado do seu <code>instanceof</code> deste jeito; por exemplo:</p>

<pre class="brush: js">class MyArray {
  static [Symbol.hasInstance](instance) {
    return this.prototype.isPrototypeOf(instance) ||
           Array.isArray(instance);
  }
}

console.log([] instanceof MyArray); // true
console.log(new MyArray instanceof MyArray); // true
console.log(new Image instanceof MyArray); // false

class MySubArray extends MyArray {}
console.log(new MySubArray instanceof MySubArray); // true
console.log(new MySubArray instanceof MyArray); // true
console.log(new MyArray instanceof MySubArray); // false</pre>

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

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('ES6', '#sec-symbol.hasinstance', 'Symbol.hasInstance')}}</td>
   <td>{{Spec2('ES6')}}</td>
   <td>Initial definition.</td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-symbol.hasinstance', 'Symbol.hasInstance')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Compatibilidade com navegadores</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>{{CompatChrome(51)}}</td>
   <td>{{ CompatGeckoDesktop(50) }}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</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>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{ CompatGeckoMobile(50) }}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="Veja_também">Veja também</h2>

<ul>
 <li>{{jsxref("Operators/instanceof", "instanceof")}}</li>
 <li>{{jsxref("Global_Objects/Object/isPrototypeOf", "isPrototypeOf()")}}</li>
</ul>