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---
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 >= 0) {
k = n;
} else {
k = len + n;
if (k < 0) {k = 0;}
}
var currentElement;
while (k < len) {
currentElement = O[k];
if (searchElement === currentElement ||
(searchElement !== searchElement && 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>
|
