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---
title: BigInt.asIntN()
slug: Web/JavaScript/Reference/Global_Objects/BigInt/asIntN
translation_of: Web/JavaScript/Reference/Global_Objects/BigInt/asIntN
---
<div>{{JSRef}}</div>
<p><strong><code>BigInt.asIntN</code></strong> 静态方法将 <code>BigInt</code> 值转换为一个 -<code>2<sup>width-1</sup></code> 与 <code>2<sup>width-1</sup>-1</code> 之间的有符号整数。</p>
<div>{{EmbedInteractiveExample("pages/js/bigint-asintn.html")}}</div>
<h2 id="语法">语法</h2>
<pre class="syntaxbox">BigInt.asIntN(<var>width</var>, <var>bigint</var>);</pre>
<h3 id="参数">参数</h3>
<dl>
<dt><code>width</code></dt>
<dd>可存储整数的位数。</dd>
<dt><code>bigint</code></dt>
<dd>要存储在指定位数上的整数。</dd>
</dl>
<h3 id="返回值">返回值</h3>
<p><code>bigint</code> 模(modulo) 2<sup><code>width</code></sup> 作为有符号整数的值。</p>
<h2 id="例子">例子</h2>
<h3 id="保持在64位范围内">保持在64位范围内</h3>
<p><code>BigInt.asIntN()</code> 方法对于保持在64位(64-bit)算数范围内非常有用。</p>
<pre class="brush: js">const max = 2n ** (64n - 1n) - 1n;
BigInt.asIntN(64, max);
// ↪ 9223372036854775807n
BigInt.asIntN(64, max + 1n);
// ↪ -9223372036854775808n
// negative because of overflow
</pre>
<h2 id="标准">标准</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
</tr>
<tr>
<td>{{SpecName('ESDraft', '#sec-bigint.asintn', 'BigInt.asIntN()')}}</td>
<td>{{Spec2('ESDraft')}}</td>
</tr>
</tbody>
</table>
<h2 id="浏览器支持">浏览器支持</h2>
<p>{{Compat("javascript.builtins.BigInt.asIntN")}}</p>
<h2 id="请参阅">请参阅</h2>
<ul>
<li>{{JSxRef("BigInt")}}</li>
<li>{{JSxRef("BigInt.asUintN()")}}</li>
</ul>
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