---
title: Array.prototype.includes()
slug: Web/JavaScript/Reference/Global_Objects/Array/includes
translation_of: Web/JavaScript/Reference/Global_Objects/Array/includes
---
<div>{{JSRef}}</div>

<p>Il metodo <code><strong>includes()</strong></code> determina se un array include un certo elemento, ritornando <code>true</code> o <code>false</code> a seconda del caso</p>

<h2 id="Sintassi">Sintassi</h2>

<pre class="syntaxbox">var <var>boolean</var> = <var>array</var>.includes(<var>searchElement</var>[, <var>fromIndex</var>])</pre>

<h3 id="Parametri">Parametri</h3>

<dl>
 <dt><code>searchElement</code></dt>
 <dd>L'elemento da cercare.</dd>
 <dt><code>fromIndex</code></dt>
 <dd>Opzionale. La posizione nell'array da cui partire per cercare l'elemento <code>searchElement</code>. Un valore negativo ricerca dal valore di <code>array.length + fromIndex</code> in maniera ascendente. Il valore di default è 0.</dd>
</dl>

<h3 id="Valore_di_ritorno">Valore di ritorno</h3>

<p>Un {{jsxref("Boolean")}}.</p>

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

<pre class="brush: js">[1, 2, 3].includes(2);     // true
[1, 2, 3].includes(4);     // false
[1, 2, 3].includes(3, 3);  // false
[1, 2, 3].includes(3, -1); // true
[1, 2, NaN].includes(NaN); // true
</pre>

<h2 id="Polyfill">Polyfill</h2>

<pre class="brush: js">if (!Array.prototype.includes) {
  Array.prototype.includes = function(searchElement /*, fromIndex*/) {
    'use strict';
    if (this == null) {
      throw new TypeError('Array.prototype.includes called on null or undefined');
    }

    var O = Object(this);
    var len = parseInt(O.length, 10) || 0;
    if (len === 0) {
      return false;
    }
    var n = parseInt(arguments[1], 10) || 0;
    var k;
    if (n &gt;= 0) {
      k = n;
    } else {
      k = len + n;
      if (k &lt; 0) {k = 0;}
    }
    var currentElement;
    while (k &lt; len) {
      currentElement = O[k];
      if (searchElement === currentElement ||
         (searchElement !== searchElement &amp;&amp; currentElement !== currentElement)) { // NaN !== NaN
        return true;
      }
      k++;
    }
    return false;
  };
}
</pre>

<h2 id="Specifications">Specifications</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('ES7', '#sec-array.prototype.includes', 'Array.prototype.includes')}}</td>
   <td>{{Spec2('ES7')}}</td>
   <td>Definizione iniziale.</td>
  </tr>
  <tr>
   <td>{{SpecName('ESDraft', '#sec-array.prototype.includes', 'Array.prototype.includes')}}</td>
   <td>{{Spec2('ESDraft')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</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>Edge</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>
    <p>{{CompatChrome(47)}}</p>
   </td>
   <td>43</td>
   <td>{{CompatNo}}</td>
   <td>14279+</td>
   <td>34</td>
   <td>9</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Android Webview</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
   <th>Chrome for Android</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatNo}}</td>
   <td>
    <p>{{CompatChrome(47)}}</p>
   </td>
   <td>43</td>
   <td>{{CompatNo}}</td>
   <td>34</td>
   <td>9</td>
   <td>
    <p>{{CompatChrome(47)}}</p>
   </td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="Vedi_anche">Vedi anche</h2>

<ul>
 <li>{{jsxref("TypedArray.prototype.includes()")}}</li>
 <li>{{jsxref("String.prototype.includes()")}}</li>
 <li>{{jsxref("Array.prototype.indexOf()")}}</li>
</ul>